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The usability and correctness of the internal pressure values as calculated by Ghaedi et al. (2017) are critically discussed. The comparison with the data based on thermodynamic relationships shows that their results are misleading. [ABSTRACT FROM AUTHOR]

In future decarbonised energy systems, residual carbon emissions require strategic planning and management. In environmental management, an evaluation of carbon removal considering local geographic frameworks is needed. This paper introduces a scalable and adaptable model for evaluating the economics and geography of future carbon capture and storage (CCS) configurations across geographical scales, covering capture, transport, and storage of carbon. The model is applied to the North Denmark Region, showing that future energy production carbon sources will be concentrated in Thisted and Jammerbugt, while industrial sources remain in Aalborg and Rebild municipalities. Carbon transport configurations, including truck, pipeline, and shipping are assessed, for the carbon to be stored in onshore and offshore geological storages. The regional scale findings suggest that pipelines and onshore storage provide the most economical configuration. However, a sensitivity study using a smaller geographical scope indicates potential for optimising carbon transport by evaluating both carbon volume and distance. The paper discusses how the model's flexibility and scalability enable the integration of alternate cost components, thereby supporting the calculation of the carbon repurposing potentials, including carbon capture, utilisation, and storage (CCUS) configurations. • Develops a scalable geographical cost model for CCS. • Quantifies CO 2 from future energy production and industrial facilities by 2045. • Estimates 2.45 million tonnes of annual capturable CO 2 for CCS by 2045. • Transport analyses show trucking and piping cost benefits for smaller CO 2 sources. • Locates infrastructure opportunities for CO 2 utilisation via CCS geographic routing. [ABSTRACT FROM AUTHOR]

In the global context, countries must reduce carbon dioxide emissions to "net zero" by 2050 to limit global warming to 1.5 °C above pre-industrial levels. China's Nationally Determined Contributions (NDCs) are to peak carbon dioxide emissions by 2030 and achieve the carbon neutrality target by 2060. To monitor the achievements of the NDCs, establishing an annual-based accounting mechanism is necessary to record the carbon stocks in China, especially for Blue Carbon. The paper aims to present China's first national-scale systematic Blue Carbon accounting for mangroves, salt marshes, and seagrasses, covering the accounting subjects of physical and monetary assets, as well as relevant indicators for investors. It focuses on the design of the accounting method and system, the selection of data categories applied to this system, and the application of China's Blue Carbon accounting based on this accounting system. Taking Blue Carbon accounting as a starting point, this paper analyses the restoration prospects of these ecosystems and their application potential for NDCs in China compared with the terrestrial ecosystems. The results indicate that mangroves are the most cost-effective type of ecosystem, even compared to terrestrial forests. Thus, the paper provides policymakers with a new perspective on the decision-making of carbon sequestration relevant decisions, aiming to promote the monitoring, restoration, and expansion of China's coastal blue carbon ecosystem through the establishment of a sound Blue Carbon accounting system, and to help achieve the carbon neutrality goal in China's NDCs through regular and systematic monitoring of its national Blue Carbon inventories. • China's coastal blue carbon ecosystems are carbon sources rather than carbon sinks. • Mangroves are the most cost-effective coastal blue carbon ecosystem compared to salt marshes and seagrass beds. • The Blue Carbon of mangroves is more cost-effective than the Green Carbon of terrestrial forests when meeting China's Nationally Determined Contributions target of increasing forest stocks. • Establishing guidelines for Blue Carbon data requirements will lay a scientific foundation for formulating strategies and policies to cope with global climate change. [ABSTRACT FROM AUTHOR]

Green roof systems have been developed to improve the environmental, economic, and social aspects of sustainability. Selecting the appropriate version of the green roof composition plays an important role in the life cycle assessment of a green roof. In this study, 10 compositions of an intensive green roof for moderate zone and 4 green roof compositions for different climatic conditions were designed and comprehensively assessed in terms of their environmental and economic impacts within the "Cradle-to-Cradle" system boundary. The assessment was carried out over a 50-year period for a moderate climate zone. The results showed that asphalt strips and concrete slab produced the highest total emissions. It was found that most greenhouse gases emissions were released in the operational energy consumption phase and in the production phase. The energy consumption phase (48.78%) for automatic irrigation and maintenance caused the highest Global Warming Potential (GWP) value (758.39 kg CO 2e) in the worst variant, which also caused the highest life cycle cost (878.47€). On the contrary, in the best variant, planting more vegetation and lower maintenance and irrigation requirements led to a reduction in GWP (445.0 kg CO 2e), but in terms of cost (506.6€) this composition didn't represent the best variant. The Global Warming Potential Biogenic (GWP-bio) compared to the Global Warming Potential Total (GWP-total) represents a proportion ranging from 0.8% to 78% depending on the proposed vegetation. Overall higher biogenic carbon values (up to 1525 kg CO 2e) were observed for the proposed tall vegetation of Magnolia, Red Mulberry, Hawthorne, Cherry, and Crab-apple Tree. Based on the results of the multicriteria analysis, which included core environmental & economic parameters, biogenic carbon emission levels, the outcome of this paper proposed optimal green roof composition. Optimal intensive green roof composition was subjected to a sensitivity analysis to determine the impact of changing climatic conditions on CO 2 emissions and life cycle costs. The results of the sensitivity analysis show that the optimal variant of the green roof can be implemented in the cold and subtropical zone with regard to CO 2 emissions, but not with regard to life cycle costs. • Ten compositions of intensive green roofs were designed and evaluated in terms of environmental and economic aspects. • Energy consumption for automatic irrigation and maintenance caused the highest GWP (48.78%) andlife cycle cost (69.55%). • The application of high green vegetation has a significant effect on CO 2 sequestration and contributes to GWP bio. • Through multicriteria analysis identified the design of the optimal green roof composition. • The most optimal composition was adapted for conditions in different climate zone. [ABSTRACT FROM AUTHOR]

Carbon dioxide capture from flue gas (CO 2 /N 2) and natural gas (CO 2 /CH 4) is a challenging and cost-effective task. In this paper, ultramicroporous metal-organic frameworks (MOFs) (Co-norf and Ni-norf) are synthesized to realize the efficient separation of CO 2 /N 2 and CO 2 /CH 4 by metal ion regulation. The Ideal Adsorption Solution Theory (IAST) was calculated to evaluate the adsorption selectivity of activated Co-norf and Ni-norf for CO 2 /N 2 (v/v = 15/85) mixtures and CO 2 /CH 4 mixtures. The CO 2 /N 2 selectivity of Co-norf and Ni-norf at 100 kPa was 734 and 96, respectively, which corresponds to an almost 7.6-fold increase by metal ion modulation. The specific binding sites of CO 2 molecules within the pore channels were obtained by grand canonical Monte Carlo simulation (GCMC). Dynamic breakthrough experiments respond to the actual separation in systems simulating flue gas and natural gas, where the higher saturation adsorption and longer retention time proved that Co-norf is an ideal material for CO 2 capture and separation. The present work provides a feasible approach for the application of MOF in gas separation. The regulation of metal ions on MOF channels is proved through single-component gas adsorption experiment, IAST selective calculation and dynamic breakthrough, which provides an effective way for the application of MOF materials in the field of gas separation. [Display omitted] • The successful synthesis of Co-norf and Ni-norf MOFs with ultramicroporous structures. • Enhanced CO 2 /N 2 and CO 2 /CH 4 selectivities achieved through metal ion regulation. • Co-norf demonstrated high separation performance for CO 2 /N 2 captures. [ABSTRACT FROM AUTHOR]

Carbon sequestration is vital to maintaining carbon neutrality and mitigating climate change's impact on humans and the environment. As the government's role in eco-advocacy is primarily designed to safeguard the environment, this paper discusses the impact of government environmental regulations on carbon sequestration. By analyzing 286 cities from 2000 to 2019 in China, we propose that government environmental regulation can lead to a 0.77% increase in carbon sequestration. Additionally, industrial agglomeration and industrial structure advancement are regarded as viable channels. As a result of the differences in city types, government intervention, and public concern across different cities, the impact is likely to vary as well. • Environmental regulation can effectively enhance carbon sequestration. • The heterogeneity considers city type, government intervention and public attention. • The mechanisms include industry agglomeration and industrial structure optimization. [ABSTRACT FROM AUTHOR]

This paper introduces an energy transition model featuring a carbon-intensive manufacturer that adopts sustainable insurance, participates in a cap-and-trade scheme, and implements carbon capture and storage (CCS) transit, all aimed at achieving the net-zero carbon emission target. The model utilizes a down-and-out call (DOC) approach to evaluate the manufacturer's equity, considering the bankruptcy risk prior to maturity due to carbon intensity. The equity of the life insurer providing funds is assessed using a capped DOC method to address the capped credit risk from the manufacturer. The findings reveal that increased adoption of CCS transit diminishes manufacturer equity, heightens default risk, and reduces insurer equity, with these effects exacerbated by advanced CCS technology and stringent cap-and-trade caps. Both stringent cap-and-trade schemes and rapid advancements in CCS transit practices, particularly with the use of advanced CCS technology, deviate from the net-zero target. A critical policy implication is the necessity for the precise calibration of cap-and-trade schemes and the pace of CCS transit adoption to ensure alignment with net-zero targets. • We develop an energy transition model with carbon capture and storage (CCS) transit. • Increased CCS transit adoption reduces manufacturer and insurer equity. • Adoption of advanced CCS technology exacerbates the effects of CCS transit adoption. • Stringent caps in cap-and-trade schemes amplify impacts of advanced CCS adoption. • Stricter cap and rapid CCS transit advancement diverge from net-zero targets. [ABSTRACT FROM AUTHOR]

Campsites can be a pollution source, mainly due to the energy consumption. In addition, the green areas, thanks to the direct CO 2 sequestration and the shading, indirectly prevent the CO 2 emissions related to energy consumption. The methodology presented in this paper allowed assessing the annual CO 2 emissions directly related to the campsite management and the consequent environmental impact in campsite clusters in Tuscany. The software i-Tree Canopy was exploited, enabling to evaluate in terms of “canopy” the tonnes of CO 2 sequestered by the vegetation within each campsite. Energy and water consumptions from 2012 to 2015 were assessed for each campsite. As far as the distribution of sequestered CO 2 is concerned, the campsites ranking was in accordance to their size. According to the indicator "T-Tree" or canopy cover, a larger area of the canopy cover allows using less outdoor areas covered by trees for the sequestration of the remaining amount of pollutants. The analysis shows that the considered campsites, that are located in a highly naturalistic Park, present significant positive aspects both in terms of CO 2 emission reductions and of energy efficiency. However, significant margins of improvement are also possible and they were analysed in the paper. [ABSTRACT FROM AUTHOR]

There is an important body of literature using multi-criteria distance function methods for the aggregation of a battery of sustainability indicators in order to obtain a composite index. This index is considered to be a proxy of the sustainability goodness of a natural system. Although this approach has been profusely used in the literature, it is not exempt from difficulties and potential pitfalls. Thus, in this paper, a significant number of critical issues have been identified showing different procedures capable of avoiding, or at least of mitigating, the inherent potential pitfalls associated with each one. The recommendations made in the paper could increase the theoretical soundness of the multi-criteria distance function methods when this type of approach is applied in the sustainability field, thus increasing the accuracy and realism of the sustainability measurements obtained. [ABSTRACT FROM AUTHOR]

There is an increasing interest in considering the effects of air pollution on ecosystem services supply in order to enhance cost-benefit analyses of air pollution policies. This paper presents a generic, conceptual approach that can be used to link atmospheric deposition of air pollutants to ecosystem services supply and societal benefits. The approach is applied in a case study in the Telemark county of Norway. First, we examine the potential effects of four European air quality policy scenarios on N deposition in the ecosystems of this county. Second, we analyse the subsequent impacts on the supply of three ecosystem services: carbon sequestration, timber production and biodiversity. Changes in the supply of the first two services are analysed in both physical and monetary units, biodiversity effects are only analysed in physical terms. The scenarios derive from work conducted in the context of the European National Emissions Ceilings Directive. In the 2010 base case the benefits of carbon sequestration are estimated at 13 million euro per year and the value of timber harvesting at 2.9 million euro per year. Under the examined policy scenarios aiming to reduce nitrogen emissions the societal benefits resulting from these two ecosystem services in Telemark are found to be reduced; the scenarios have little effect on terrestrial biodiversity. Such results cannot be scaled up, individual ecosystem services respond differently to changes in air pollution depending upon type of pollutant, type of ecosystem, type of service, and the magnitude of change. The paper further presents an analysis of the uncertainties that need to be considered in linking air pollution and ecosystem services including those in deposition rates, ecosystem responses, human responses and in the values of ecosystem services. Our conceptual approach is also useful for larger scale analysis of air pollution effects on ecosystem services, for example at national or potentially European scale. [ABSTRACT FROM AUTHOR]

In this paper, we propose a multi-RREH (Remote Renewable Energy Hub) based optimization framework. This framework allows a valorization of CO 2 using carbon capture technologies. This valorization is grounded on the idea that CO 2 gathered from the atmosphere or post combustion can be combined with hydrogen to produce synthetic methane. The hydrogen is obtained from water electrolysis using renewable energy. Such renewable energy is generated in RREH, which are locations where RE is cheap and abundant (e.g., solar PV in the Sahara Desert, or wind in Greenland). We instantiate our framework on a case study focusing on Belgium and 2 RREH, and we conduct a techno-economic analysis under uncertainty. This analysis highlights, among others, the interest in capturing CO 2 via Post Combustion Carbon Capture (PCCC) rather than only through Direct Air Capture (DAC) for methane synthesis in RREH. By doing so, a notable reduction of 10% is observed in the total cost of the system under our reference scenario. In addition, we use our framework to derive a carbon price threshold above which carbon capture technologies may start playing a pivotal role in the decarbonation process of our industries. • We demonstrate PCCC technology potential for reducing RREH's CH4 production cost. • We derive a carbon price threshold for crucial industrial decarbonization. • An uncertainty analysis has been carried out on the reference scenario. [ABSTRACT FROM AUTHOR]

At present, biochar has a large application potential in soil amelioration, pollution remediation, carbon sequestration and emission reduction, and research on the effect of biochar on soil ecology and environment has made positive progress. However, under natural and anthropogenic perturbations, biochar may undergo a series of environmental behaviors such as migratory transformation, mineralization and decomposition, and synergistic transport, thus posing certain potential risks. This paper outlines the multi-interfacial migration pathway of biochar in "air-soil-plant-animal-water", and analyzes the migration process and mechanism at different interfaces during the preparation, transportation and application of biochar. The two stages of the biochar mineralization process (mineralization of easily degradable aliphatic carbon components in the early stage and mineralization of relatively stable aromatic carbon components in the later stage) were described, the self-influencing factors and external environmental factors of biochar mineralization were analyzed, and the mineral stabilization mechanism and positive/negative excitation effects of biochar into the soil were elucidated. The proximity between field natural and artificially simulated aging of biochar were analyzed, and the change of its properties showed a trend of biological aging > chemical aging > physical aging > natural aging, and in order to improve the simulation and prediction, the artificially simulated aging party needs to be changed from a qualitative method to a quantitative method. The technical advantages, application scope and potential drawbacks of different biochar modification methods were compared, and biological modification can create new materials with enhanced environmental application. The stability performance of modified biochar was compared, indicating that raw materials, pyrolysis temperature and modification method were the key factors affecting the stability of biochar. The potential risks to the soil environment from different pollutants carried by biochar were summarized, the levels of pollutants released from biochar in the soil environment were highlighted, and a comprehensive selection of ecological risk assessment methods was suggested in terms of evaluation requirements, data acquisition and operation difficulty. Dynamic tracing of migration decomposition behavior, long-term assessment of pollution remediation effects, and directional design of modified composite biochar materials were proposed as scientific issues worthy of focused attention. The results can provide a certain reference basis for the theoretical research and technological development of biochar. [Display omitted] • Analyzed the migration process and mechanism of biochar at different interfaces. • Analyzed the mineralization process and stability mechanism of biochar in soil. • Compared the properties of biochar under artificial simulation and natural aging. • Summarized the modification strategies and characterization methods of biochar. • Summarized the potential environmental risks in the application process of biochar. [ABSTRACT FROM AUTHOR]

The present paper compared, through life cycle assessment (LCA), the production of aviation biofuel from two hydrothermal routes of microalgae cultivated in wastewater. Hydrothermal liquefaction (HTL) and gasification followed by Fischer-Tropsch synthesis (G + FT) were compared. Both routes included biomass production, hydrotreatment for biofuel upgrading, and product fractionation. Secondary data obtained from the literature were used for the cradle-to-gate LCA. G + FT had a higher impact than HTL in the 18 impact categories assessed, with human carcinogenic toxicity exerting the most harmful pressure on the environment. The catalysts were the inputs that caused the most adverse emissions. The solvent used for bio-oil separation also stood out in terms of impacts. In HTL, emissions for global warming were −51.6 g CO 2 eq/MJ, while in G + FT, they were 250 g CO 2 eq/MJ. At the Endpoint level, HTL resulted in benefits to human health and ecosystems, while G + FT caused environmental damage in these two categories, as well as in the resources category. In the improvement scenarios, besides considering solid, aqueous, and gaseous products as co-products rather than just as waste/emissions, a 20% reduction in catalyst consumption and 90% recovery were applied. Thus, in HTL, 39.47 kg CO 2 eq was avoided, compared to 35.44 kg CO 2 eq in the base scenario. In G + FT, emissions decreased from 147.55 kg CO 2 eq to the capture of 8.60 kg CO 2 eq. [Display omitted] • Gasification + Fischer-Tropsch caused more impacts than liquefaction. • The environment has suffered more harmful pressure on human carcinogenic toxicity. • The catalysts used were the inputs that most caused adverse emissions. • Liquefaction route captured 39.47 kg CO 2 eq with improvement scenario. • Gasification + Fischer-Tropsch captured 8.6 kg CO 2 eq with the improvement scenario. [ABSTRACT FROM AUTHOR]

This research paper delves into the intricate interplay between decarbonisation and sustainability, focusing on adopting chemical looping technologies. Deep decarbonisation scenarios necessitate a profound transformation in various sectors to mitigate climate change, and oil refineries, as pivotal players, must adapt to these changes. Employing the BLUES integrated assessment model, we evaluate the evolution of the refining sector in decarbonisation pathways, emphasising its potential for sustainability through repurposing and emissions mitigation. Additionally, we delve into chemical looping technologies, including Solar Thermal Chemical Looping (STCL), Reverse Water Gas Shift Chemical Looping (RWGS-CL), Chemical Looping Reforming (CLR), and Super Dry Reforming (SDR), elucidating their principles and contributions to carbon dioxide (CO 2) conversion. These technologies offer promising routes for CO 2 capture and present opportunities for sustainable carbon loop cycles, potentially revolutionising industries' emissions reduction efforts. In a world of climate change, this research illuminates a sustainable path forward by integrating decarbonisation and innovative CO 2 management strategies. • Chemical looping technologies offer innovative routes for sustainable carbon capture and utilisation. • Oil refineries can play a pivotal role in reducing emissions through asset repurposing. • Integration of the BLUES model provides insights into refining sector evolution for decarbonisation. • Solar Thermal Chemical Looping (STCL) utilises solar energy for CO 2 conversion. • Methane-utilising CO 2 CL processes like CLR and SDR offer promising sustainability solutions. [ABSTRACT FROM AUTHOR]

The extensive amount of available information on global warming suggests that this issue has become prevalent worldwide. Majority of countries have issued laws and policies in response to this concern by requiring their industrial sectors to reduce greenhouse gas emissions, such as CO 2 . Thus, introducing new and more effective treatment methods, such as biological techniques, is crucial to control the emission of greenhouse gases. Many studies have demonstrated CO 2 fixation using photo-bioreactors and raceway ponds, but a comprehensive review is yet to be published on biological CO 2 fixation. A comprehensive review of CO 2 fixation through biological process is presented in this paper as biological processes are ideal to control both organic and inorganic pollutants. This process can also cover the classification of methods, functional mechanisms, designs, and their operational parameters, which are crucial for efficient CO 2 fixation. This review also suggests the bio-trickling filter process as an appropriate approach in CO 2 fixation to assist in creating a pollution-free environment. Finally, this paper introduces optimum designs, growth rate models, and CO 2 fixation of microalgae, functions, and operations in biological CO 2 fixation. [ABSTRACT FROM AUTHOR]

Despite increasing interest, a lack of comprehensive knowledge regarding the efficient design and implementation of carbon farming schemes remains. These schemes must efficiently achieve higher carbon sequestration, incentivize farmers, and increase farmers' participation in global carbon markets. Our study systematically reviews, describes, and maps available evidence related to carbon farming contracts to assess different incentive mechanisms for carbon farming. We conduct a systematic mapping review of articles extracted from various databases employing the Collaboration for Environmental Evidence method. We shortlist 52 articles and analyze about 40 global case studies, identifying three main incentive mechanisms of carbon farming contracts, namely, result-based, action-based, and hybrid payments. We examine how these incentive mechanisms are designed, in addition to associated payment types, monitoring approaches, and barriers to implementation. Result-based payments include stringent monitoring and can be implemented through auctions, carbon credits, product labels or certificates. Action-based payments are found to be simpler, with lower monitoring requirements for farmers and can be paid upfront or after contract implementation. Hybrid payments combine both techniques, offering low-risk and guaranteed payments for farmers and definite environmental mitigation impacts. Result-based and hybrid payments motivate farmers to innovate to meet environmental objectives while also connecting them to carbon markets. The major challenges to developing a successful carbon farming project include lack of permanence, non-additionality, and the absence of stringent monitoring, reporting, and verification standards, all of which affect farmers' incentives. This study determines that carbon farming contract design and efficiency can be improved by analyzing the lessons learned from previous experiences. By examining and improving the attributes that define different incentive mechanisms, farmers can be better motivated to enroll in carbon farming schemes and benefit from increased access to carbon markets to potentially transform agriculture into a viable tool for climate action. • Systematic mapping reviewed 52 papers, which encompassed 40 global cases. • Three incentive mechanisms: result-based, action-based, and hybrid payments. • Results-based payments: stringent MRV, high risk but high profitability to farmers. • Action-based payments: simple MRV, low risk but low profitability to farmers. • Hybrid payment: low-risk and high profitability; connect farmers to carbon markets. [ABSTRACT FROM AUTHOR]

Calcium carbide residue (CCR) is a waste obtained from the production of acetylene gas by the hydration reaction of calcium carbide. This residue is generated in large quantities annually and requires appropriate disposal. The main composition of the residue is calcium hydroxide (Ca(OH) 2). Ca(OH) 2 can react with CO 2 gas and form CaCO 3 particles. This process is well known but not very attractive since Ca(OH) 2 is obtained from limestone using an energy-intensive thermal conversion process. This paper examined the synthesis of CaCO 3 from CCR solutions by capturing CO 2 with the aid of triethanolamine (TEA) solutions at doses of 0, 5, 10 and 20% w/w. The precipitated CaCO 3 was characterized, and the application of CaCO 3 as a filler in epoxy resin was tested. The results showed that the precipitated CaCO 3 was mainly calcite, with a 76.6% yield. Cubic calcite was primarily obtained in TEA solutions, whereas small and agglomerated spherical vaterite and cubic calcite particles were formed in non-TEA solutions. The CaCO 3 -filled epoxy composites showed higher compressive strength than the neat resin. However, the transparency of specimen plates was reduced. These results can serve as guidelines for the application of CCR slurry filtrate obtained from the sedimentation ponds of acetylene plants and help to reduce the amount of wastewater that needs to be treated. CO 2 gas from industrial flue gas combined with TEA solution could be applied to precipitate CaCO 3 for carbon-neutral manufacturing. • CaCO 3 was synthesized from CCR solutions by capturing CO 2 /triethanolamine. • Precipitated CaCO 3 was mainly cubic calcite with 76.6% yield. • Compressive strength of CaCO 3 -filled epoxy composites was improved. • Transparency of CaCO 3 -filled specimen plates was reduced to translucent object. [ABSTRACT FROM AUTHOR]

In recent years, the importance of capturing CO 2 has increased due to the necessity of minimizing climate change and the detrimental effects of CO 2 emissions from industrial processes. CO 2 absorption, as one of the most mature carbon capture technologies, has been improved by introducing nanosized particles into liquid absorbents. Nanofluids have been the subject of interest in many studies recently due to their tremendous impact on absorption. This review comprehensively examines the CO 2 absorption behavior for nanofluids through the investigation of different absorption systems. Potential mechanisms for improving the absorption/regeneration performance of nanoabsorbents as well as the synergistic effects of physicochemical properties of nanofluids, such as viscosity and density on CO 2 capture behavior, are reviewed. Nanofluid enhancement factors in terms of absorption rate and capacity towards CO 2 are also compiled. Mathematical models, which have been proposed for calculating mass transfer coefficient and mass diffusivity, are comprehensively outlined. The paper discusses conventional methods for nanofluid preparation affecting the physicochemical properties of nanofluids. Strategies for enhancing nanofluid stability, as well as approaches to examine their stability are discussed. Finally, nanoparticle concentration, types and size of them, and selection of the base liquid absorbent as the key factors influencing the CO 2 removal process by nanofluids, are considered in this paper, as well. [Display omitted] • Synthesis of nanofluids (NFs) and techniques to promote and inspect their stability. • Experimental apparatus and calculation methods for CO 2 absorption by NFs. • Mathematical models for estimating mass transfer coefficient and diffusivity in NFs. • Effective factors in enhancement of nanofluids' CO 2 absorption capacity and rate. [ABSTRACT FROM AUTHOR]

The rapid transformation of natural forest areas into fast-growing exotic species plantations, where the main objective is timber and pulp production, has led to a neglect of other services forests provide in many parts of the world. One example of such a problem is the county of Biscay, where the management of these plantations has negative impacts on the environment, creating the necessity to evaluate alternative tree species for use in forestry. The actual crisis in the forest sector of the region could be an opportunity to change to native species plantations that could help restore ecosystem structure and function. However, forest managers of the region are using the current interest on carbon sequestration by forest to persist with the “pine and eucalyptus culture”, arguing that these species provide a big C sequestration service. Moreover, they are promoting the expansion of eucalyptus plantations to obtain biomass for the pulp and paper industry and for bioenergy. The aim of this paper is to answer the following questions: Is this argument used by the foresters well-founded? or, could the use of native species in plantations improve the C sequestration service in Biscay while avoiding the environmental problems the actual plantations cause? To answer these questions we created three alternative future scenarios: a) the Services scenario, where there is a substitution of fast-growing exotic plantations by native broadleaf species plantations; b) the Biomass scenario, where there is a bet on eucalyptus plantations; and c) the Business as usual scenario. The changes in the C stock in living biomass in these scenarios have been simulated by a hybrid approach utilising inventories and models, and the period considered was 150 years. Our results show that the substitution of existing exotic plantations by plantations of native species has the greatest potential for increasing C sequestration. Although short- and mid-term outcomes may differ, when the long-term (more than 50 years) is considered, the C stock in the living biomass in the Services scenario is the greatest, accumulating 38% more C than the Business as usual scenario and 70% more C than the Biomass scenario at the end of the study period. Thus, changing pine and eucalyptus by native species in plantations, while solving some of the environmental problems of the actual plantations, sequesters more C in the long-term. As C sequestration initiatives only make sense if there is a good chance of long-term persistence of the C stocks created, there is no C sequestration argument for the foresters to continue with the actual policy of the use of fast-growing exotic species. [Copyright &y& Elsevier]

Due to lower-cost energy supplies elsewhere, Europe needs resource efficient technologies to safeguard the competitiveness of its energy-intensive industries. The technical feasibility of the CCU value chain components (carbon capture, transportation and utilization) has been widely studied in literature. However infrastructural, regulatory and business strategic issues have received less attention. A review of the relevant policies (e.g. European Emissions Trading Scheme, Renewable Fuels and Waste Directives) has been performed. Stakeholder engagement and the stakeholder influence mapping was used to examine potential climate change, circular economy, renewable energy and regional industrial development policies that can support CO 2 utilization value chains. The main contribution of the paper is to outline potential benefits of policies to foster the production and uptake of CO 2 -derived products such as methanol, polyurethane and mineral construction aggregates. Another outcome is to illustrate the role of key policy-making stakeholders in assessing the suitability of current statutes and the impact of potential changes. An important finding was that the development of connectivity infrastructure is a key missing enabler and more attention to policy on infrastructure is required. Finally, the work examines the justification for a CO 2 Utilization Directive, comparable to the Carbon Capture and Storage Directive, but considering the current complexity of the European Union (EU) policy landscape. • Analysis of all European policies relevant to the development of CO2 utilization. • Stakeholder influence analysis for the future development of CCU policy. • Recommendation to consider CO2 as a material for the circular economy. • Stakeholder engagement with industry participants and European institutions. • Rationale for regional burden sharing of risk in developing CCU infrastructure. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization and sequestration technology is effective for carbon emissions reduction. The development of new absorbent seems to be one of the core components of carbon capture technology. In this paper, three esters, methyl heptanoate, ethyl hexanoate and methyl benzoate, were selected to determine CO 2 solubilities at different temperatures ranging from 293.15 to 333.15 K, and pressures up to 1.2 MPa, using the isothermal synthesis method. The results showed that the absorbent with the straight-chain alkyl group was more effective for improving CO 2 absorption capacity than the benzene group. Ethyl hexanoate showed slightly higher CO 2 solubilities than its isomer methyl heptanoate. In addition, Henry’s constant and thermodynamic properties such as solution enthalpy, solution entropy, solution Gibbs energy and solution heat capacity, were determined based on the measured data since the above properties are essential for designing an absorption process. Ethyl hexanoate is superior to the other two selected absorbents, common solvents, commercial absorbents, some physical absorbents, some polymeric absorbents and some ionic liquids, which indicates that it has potential value for CO 2 capture technology. However, further studies will be necessary to assess the reliability of its industrial application. [ABSTRACT FROM AUTHOR]

Abstract: The potential to capture carbon from industrial sources and dispose of it for the long-term, known as carbon capture and sequestration (CCS), is widely recognized as an important option to reduce atmospheric carbon dioxide emissions. Specifically, CCS has the potential to provide emissions cuts sufficient to stabilize greenhouse gas levels, while still allowing for the continued use of fossil fuels. In addition, CCS is both technologically-feasible and commercially viable compared with alternatives with the same emissions profile. Although the concept appears to be solid from a technical perspective, initial public perceptions of the technology are uncertain. Moreover, little attention has been paid to developing an understanding of the social and political institutional infrastructure necessary to implement CCS projects. In this paper we explore a particularly dicey issue—how to ensure adequate long-term monitoring and maintenance of the carbon sequestration sites. Bonding mechanisms have been suggested as a potential mechanism to reduce these problems (where bonding refers to financial instruments used to ensure regulatory or contractual commitments). Such mechanisms have been successfully applied in a number of settings (e.g., to ensure court appearances, completion of construction projects, and payment of taxes). The paper examines the use of bonding to address environmental problems and looks at its possible application to nascent CCS projects. We also present evidence on the use of bonding for other projects involving deep underground injection of materials for the purpose of long-term storage or disposal. [Copyright &y& Elsevier]

This paper evaluates the potential use of date palm leaf biochar as a climate change solution through CO 2 capture and sequestration. The pyrolysis of date palm leaf was performed at different temperatures 300°, 400°, 500°, and 600 °C. The physicochemical characteristics of the synthesized biochar were examined using Scanning Electron Microscopy (SEM) with Energy Dispersive X-Ray Analysis (EDX), Fourier transforms infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), and X-ray diffraction analysis (XRD). Direct gas-solid interaction was carried out in an integrated Fluidized Bed Reactor (FBR), connected with a gas analyzer for maximum and effective mixing between the biochar and CO 2. LabView program was used as data acquisition for an instantaneous calculation of CO 2 adsorption. This study showed that the date palm biochar as porous carbon-based materials has high CO 2 adsorption capacity through physisorption and chemisorption progressions. The adsorption results showed a maximum CO 2 capture percentage of 0.09 kg CO 2 /kg, 0.15 kg CO 2 /kg, 0.20 kg CO 2 /kg, and 0.25 kg CO 2 /kg palm biochar synthesized at 300 °C, 400 °C, 500 °C, and 600 °C, respectively. This paper paid attention to the inexpensive technology applied in CO 2 sequestration, where fluidization provides well mixing of biochar particles with low operation cost. • This study aims to prepare different biochar from date palm leaf (DPL) waste and evaluate its CO 2 capture and sequestration capacity. • Biochar samples were pyrolyzed at different temperatures and were characterized using SEM-EDS, FTIR, TGA, and XRD. • The gas-solid reaction was achieved in the integrated fluidized bed reactor on the different DPL biochar particles. Results indicated that the DPL biochar has a high CO 2 adsorption capacity. • The CO 2 sequestration of the DPL ranged from 07 to 25%, based on different temperatures of biochar pyrolysis. [ABSTRACT FROM AUTHOR]

Reducing greenhouse gases in the atmosphere is becoming a pressing issue for the global community. Afforestation and reforestation are promoted worldwide as an effective means of sequestering carbon. For its national interest and global concerns, China has made great efforts to protect its existing forests and develop programs of afforestation and reforestation. Based on two surveys recently conducted in Liping County, Guizhou province, this paper investigates the economic changes associated with the implementation of the “Grain For Green” policy. Based on the analytical framework of benefit cost analysis, this paper concludes that the implementation of the reforestation of sloping agricultural land policy would not be possible if there were no government subsidies for the peasants. The short term economic returns of land and labour from forestation are substantially lower than those generated from grain or cash crop production on the steep slope lands. The government subsidies provide great economic incentives for peasants to take part in the project. The subsidies in fact have elevated peasant income in rural Liping. The estimated potential economic returns of plantations over the long run indicate that the removal of the government financial subsidies would not create an economic crisis for the peasants if the current market conditions continue. [Copyright &y& Elsevier]

This paper introduces an integrated assessment (IA) approach for a Canada-China joint research project that linked forest carbon sequestration, forest resource management, and local sustainability enhancement. The purpose of the IA was to improve the measurement of carbon in different land uses and vegetation covers, as well as to direct decision makers to those land uses or options as an CO2 emission reduction strategy while supporting rural sustainable development. In this connection, three questions are addressed in this paper: [1)] How will forestry carbon sequestration land use policies affect regional sustainability prospects in rural China? [2)] How could carbon sequestration land use plans be better integrated into sustainable development strategies? and [3)] How can the IA approach assist Chinese government agencies in design effective forestry land use policies? The IA approach was applied in three rural sites of western China. These case studies are described in detail by following articles in this volume. The project improved the capacity of local resource managers in identifying the economic, social and environmental impacts of rural land use decisions that might increase carbon sequestration and enhance local livelihood. [Copyright &y& Elsevier]

Abstract: The Kyoto Protocol provides for the involvement of developing countries in an atmospheric greenhouse gas reduction regime under its Clean Development Mechanism (CDM). Carbon credits are gained from reforestation and afforestation activities in developing countries. Bangladesh, a densely populated tropical country in South Asia, has a huge degraded forestland which can be reforested by CDM projects. To realize the potential of the forestry sector in developing countries for full-scale emission mitigation, the carbon sequestration potential of different species in different types of plantations should be integrated with the carbon trading system under the CDM of the Kyoto Protocol. This paper discusses the prospects and problems of carbon trading in Bangladesh, in relation to the CDM, in the context of global warming and the potential associated consequences. The paper analyzes the effects of reforestation projects on carbon sequestration in Bangladesh, in general, and in the hilly Chittagong region, in particular, and concludes by demonstrating the carbon trading opportunities. Results showed that tree tissue in the forests of Bangladesh stored 92tons of carbon per hectare (tC/ha), on average. The results also revealed a gross stock of 190tC/ha in the plantations of 13 tree species, ranging in age from 6 to 23 years. The paper confirms the huge atmospheric CO2 offset by the forests if the degraded forestlands are reforested by CDM projects, indicating the potential of Bangladesh to participate in carbon trading for both its economic and environmental benefit. Within the forestry sector itself, some constraints are identified; nevertheless, the results of the study can expedite policy decisions regarding Bangladesh''s participation in carbon trading through the CDM. [Copyright &y& Elsevier]

To mitigate global warming and the greenhouse effect, biochar (BC) has been regarded as an important way of carbon sink. Therefore, this research explored the development trend of BC for soil carbon sequestration and mitigation from 2001 to 2020 based on bibliometric analysis. The results show that Yong Sik Ok and Johannes Lehmann are the top 2 high-impact authors. China, America, and Germany are the most widely collaborated countries, but China's research impact is lower than that of America. The Chinese Academy of Sciences has far more publications than any other institution, but Cornell University and Kangwon National University lead the way in terms of impact. Research hotspots can be divided into five clusters: (1) pyrolysis, nutrient, and microbial communities; (2) the immobilization of heavy metals; (3) crop yield and soil properties; (4) greenhouse gas, meta-analysis, and field experiment; (5) carbon fraction and sequestration. Reviews account for 60 % of the top 10 most highly cited papers, and eight of the top 10 focus on the early research period, setting the stage for the development of the BC field. Science of the Total Environment has the highest number of publications and total citations, and literature published in Soil Biology and Biochemistry is to some extent more likely to be cited. In the future, we need to carry out research in the following aspects: (1) Interaction mechanisms between BC, soil, and soil microbial communities. (2) Designing low-cost, high-yield, and high-effect optimization methods to improve the characteristics of BC. (3) Effect of BC on the environment and human health in long-term localization experiments. (4) Carbon sinks of BC need to be further evaluated on a global scale. [Display omitted] • The research progress was reviewed by bibliometrics analysis and bibliometrics. • China, America, and Germany are the most widely collaborated countries. • Research hotspots can be divided into five categories by cluster analysis. • The prospects of biochar for carbon sequestration and mitigation are presented. [ABSTRACT FROM AUTHOR]

This paper provides a perspective for comparing trade-offs between harvested wood flows and forest carbon stocks with different forest management regimes. A constant management regime applied to a forest area with an even age-class distribution leads to a steady state, in which the annual harvest and carbon stocks remain constant over time. As both are desirable – carbon stocks for mitigating climate change and harvests for the economic use of wood and displacing fossil fuels – an ideal strategy should be chosen from a set of management regimes that are Pareto-optimal in the sense of multi-criteria decision-making. When choosing between Pareto-optimal alternatives, the trade-off between carbon stock and harvests is unavoidable. This trade-off can be described e.g. in terms of carbon payback times or carbon returns. As numerical examples, we present steady-state harvest levels and carbon stocks in a Finnish boreal forest region for different rotation periods, thinning intensities and collection patterns for harvest residues. In the set of simulated management practices, harvest residue collection presents the most favorable trade-off with payback times around 30–40 years; while Pareto-optimal changes in rotation or thinnings exhibited payback times over 100 years, or alternatively carbon returns below 1%. By extending the rotation period and using less-intensive thinnings compared to current practices, the steady-state carbon stocks could be increased by half while maintaining current harvest levels. Additional cases with longer rotation periods should be also considered, but were here excluded due to the lack of reliable data on older forest stands. [ABSTRACT FROM AUTHOR]

Coastal wetlands sequester large amounts of carbon in their soils, effectively removing carbon dioxide from the atmosphere and acting as a carbon sink. In this paper, we estimate the economic value of carbon sequestered by wetlands in the Delaware Estuary. We estimate the value of the current stock of wetlands, the value of the historic loss of wetlands, and under a range of different scenarios the expected future loss. We use historical topographic maps and Land Cover inventories of the Delaware Estuary to measure the acreage of tidal wetlands in nine distinct time periods from 1778 to 2011. Using these data, we estimate an annual rate of wetland loss of 1.03 km 2 . Coupling observed land cover change with exogenous factors including sea-level rise, population pressure, and channel dredging, we estimate changes in tidal wetland area under a range of future scenarios for our expected future economic loss estimates. [ABSTRACT FROM AUTHOR]

Carbon sequestration in concrete has attracted increasing research attention. CO 2 may be permanently stored in the cement paste of concrete by chemical reaction with the hydration products of cement, but this method leads to a significant reduction of the pH value of the concrete pore solution and may thus put the steel reinforcement at risk of corrosion. This paper proposes a new method for carbon sequestration in concrete using the space in porous coarse aggregates; the method involves presoaking the porous aggregates in an alkaline slurry and then using them for CO 2 sequestration. The potential of utilising the space in the porous aggregates and the cations in the alkaline slurry is first discussed. An experimental study aiming to demonstrate the feasibility of the proposed method is then presented. The results show that CO 2 can be successfully sequestrated and fixed as CaCO 3 in the open pores of coarse coral aggregate presoaked in a Ca(OH) 2 slurry. The amount of CO 2 sequestration by concrete produced using the presoaked coral aggregate was around 20 kg/m3. Importantly, the proposed CO 2 sequestration method did not affect the strength development of the concrete or the pH value of the concrete pore solution. • A new method for CO2 sequestration in concrete using the space in porous aggregates is proposed. • Porous aggregates with alkaline slurry soaking have excellent potential for CO2 sequestration. • The amount of CO2 sequestration by concrete with the porous aggregates was around 20 kg/m3. • The CO2 sequestration method has little effect on the pH value of the concrete pore solution. [ABSTRACT FROM AUTHOR]

Nowadays, there is an increasing use of digital technologies and Artificial Intelligence (AI) such as Machine Learning (ML) models that leverage data to optimize the performances of systems in almost all activity sectors, including ML models for optimizing solutions related to CO2 capture from the atmosphere or CO2 emissions reduction from human activities. However, on the other hand, the use of AI models is leading to an increasing energy consumption that also raises environmental issues (in terms of CO2 emissions) which are less studied in the literature. This then raises the new question of a more realistic estimate of the carbon footprint (CO2 emissions in particular) of AI models in general, and particularly AI models aimed at reducing CO2 emissions. Thus, in this paper, for an AI model in this latter context, we propose a method to quantify both his negative impacts (quantity of CO2 emissions emitted by the training and use of the model) and his positive impacts (quantity of CO2 emissions saved when the model is used). The method is evaluated with three state-of-the-art AI models: (i) an artificial neural network model for managing the energy demand of Brazilian households, (ii) an adaptive neuro-fuzzy inference system for photovoltaic power forecast in Tunisia, (iii) and a Bayesian regression model for the electric vehicle routing problem in Sweden and Luxembourg. Results show that, if only the positive impacts are considered, the reduction of CO2 emitted due to the usage of the models is significant, but depends on each context (34%, 73%, and 9%, respectively). However, when both positive and negative impacts are considered, the negative impacts are sometimes higher than the positive impacts (the first and the third model) for a nominal use (1 user). Nevertheless, the balance becomes highly positive again, when these two projects are scaled up (realistic projections with many users). The second model cannot be scaled up, but the balance remains positive, even if the gains are much smaller. More generally, the CO2 emissions gain metrics provided by our method can be used as new metrics for comparing the efficiency of AI models (for reducing CO2 emissions) beyond predictive capacity-based traditional ML evaluation metrics. Based on the lessons learned from our study, we also provide seven global recommendations that can contribute to the reduction of the carbon footprint of ML models in general. • Increase of the use of AI models for optimizing solutions to reduce CO2 emissions. • Training and using AI models also generates CO2 emissions. • Method to quantify positive and negative environmental impacts of AI models. • Evaluations based on three state-of-the-art AI models. • Seven global recommendations for reducing CO2 emissions of AI models. [ABSTRACT FROM AUTHOR]

Increasing soil organic carbon (SOC) stocks in agricultural soils removes carbon dioxide from the atmosphere and contributes towards achieving carbon neutrality. For farmers, higher SOC levels have multiple benefits, including increased soil fertility and resilience against drought-related yield losses. However, increasing SOC levels requires agricultural management changes that are associated with costs. Private soil carbon certificates could compensate for these costs. In these schemes, farmers register their fields with commercial certificate providers who certify SOC increases. Certificates are then sold as voluntary emission offsets on the carbon market. In this paper, we assess the suitability of these certificates as an instrument for climate change mitigation. From a soils' perspective, we address processes of SOC enrichment, their potentials and limits, and options for cost-effective measurement and monitoring. From a farmers' perspective, we assess management options likely to increase SOC, and discuss their synergies and trade-offs with economic, environmental and social targets. From a governance perspective, we address requirements to guarantee additionality and permanence while preventing leakage effects. Furthermore, we address questions of legitimacy and accountability. While increasing SOC is a cornerstone for more sustainable cropping systems, private carbon certificates fall short of expectations for climate change mitigation as permanence of SOC sequestration cannot be guaranteed. Governance challenges include lack of long-term monitoring, problems to ensure additionality, problems to safeguard against leakage effects, and lack of long-term accountability if stored SOC is re-emitted. We conclude that soil-based private carbon certificates are unlikely to deliver the emission offset attributed to them and that their benefit for climate change mitigation is uncertain. Additional research is needed to develop standards for SOC change metrics and monitoring, and to better understand the impact of short term, non-permanent carbon removals on peaks in atmospheric greenhouse gas concentrations and on the probability of exceeding climatic tipping points. Overview of the challenges associated with using soil carbon certificates as privately traded, voluntary emission offsets. [Display omitted] • Soil-based carbon certificates are sold as voluntary emission offsets. • Private certification schemes provide financial incentives for carbon farming. • However, they are not a suitable tool for climate change mitigation. • Permanence, additionality and monitoring are not ensured; leakage effects may occur. • Accountability in case of re-emissions of stored carbon is low. [ABSTRACT FROM AUTHOR]

The carbonation of alkaline wastes is an interesting research field that may offer opportunities for CO 2 reduction. However, the literature is mainly devoted to studying different waste sequestration capabilities, with lame attention to the reliability of the data about CO 2 reduction, or to the possibilities to increase the amount of absorbed CO 2. In this work, for the first time, the limitation of some methods used in literature to quantify the amount of sequestered CO 2 is presented, and the advantages of using suitable XRD strategies to evaluate the crystalline calcium carbonate phases are demonstrated. In addition, a zero-waste approach, aiming to stabilize the waste by coupling the use of by-products and the possibility to obtain CO 2 sequestration, was considered. In particular, for the first time, the paper investigates the differences in natural and accelerated carbonation (NC and AC) mechanisms, occurring when municipal solid waste incineration (MSWI) fly ash is stabilized by using the bottom ash with the same origin, and other by-products. The stabilization mechanism was attributed to pozzolanic reactions with the formation of calcium silicate hydrates or calcium aluminate hydrate phases that can react with CO 2 to produce calcium carbonate phases. The work shows that during the AC, crystalline calcium carbonate was quickly formed by the reaction of Ca(OH) 2 and CaClOH with CO 2. On the contrary, in NC, carbonation occurred due to reactions also with the amorphous Ca. The sequestration capability of this technology, involving the mixing of waste and by-products, is up to 165 gCO 2 /Kg MSWI FA, which is higher than the literature data. [Display omitted] • The limitations of some methods used to quantify the sequestrated CO2 are presented. • The use of XRD to evaluate the crystalline calcium carbonate phases is validated. • An approach, aiming to stabilize fly ash and obtain CO2 sequestration, is considered. • In the first hours, CaCO3 is formed by the reaction of Ca(OH)2 and CaClOH with CO2. • After the first days, carbonation occurs due to a reaction with the amorphous. [ABSTRACT FROM AUTHOR]

Converting industrial wastes into value-added building products in an environmental management strategy is a challenging yet vital component of the industrial process. Steel slag (SS), an industrial waste by-product from the steel-making process, is typically disposed of in landfill which consumes land resources and pollutes the environment. This paper explores the possibility of a closed-loop system to convert steel slag into a cement material through carbonation activation, thereby significantly reducing the amount of steel slag waste sent to landfills across Canada. The production of this cementing material can occur next to the steel mill, utilizing steel slag and carbon dioxide collected on-site to fabricate carbon-negative products. To save energy and allow production to be feasible on an industrial scale, ambient pressure (AP) carbonation is developed to reduce carbon emissions while improving their performance. High pressure (HP) carbonation curing and normal hydration (NH) references were also implemented at the same time to justify the application of AP carbonation in reducing CO 2 emission. The results of this study found AP carbonation-activated SS compacts have comparable CO 2 uptake (about 7.5 tons CO 2 /100 tons slag) and mechanically compressive strength values as those subjected to HP carbonation, suggesting that AP could be used to replace HP in carbonation curing to ensure a lower energy input. Additionally, AP seemed to possess as effective carbonation as HP. The studies investigated by multiple techniques including X-ray diffractometer (XRD), thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopic analysis, and scanning electron microscopy (SEM) aim to identify the microstructure development of carbonated SS paste to assess carbonation results. Developed with life cycle assessment (LCA), environmental impact evaluation shows that AP presents a smaller global warming potential (GWP) value than HP. The comparable CO 2 sequestration, satisfactory engineering properties, enhanced microstructure and lesser environmental impact in AP carbonation confirm the feasibility of replacing high pressure with extremely low pressure to cure concrete products. The use of AP carbonation for cement material created using steel slag reduces carbon emissions, energy usage, and natural resource consumption. • Ambient pressure can be used to replace high pressure in early carbonation curing. • Ambient pressure carbonation can turn steel slag into a clean cementing material. • The production of carbon-negative products can be set next to the steel mill. • Ambient pressure carbonation presents a relatively uniform and effective reaction. • Life cycle assessment confirms ambient pressure carbonation reduces CO 2 emission. [ABSTRACT FROM AUTHOR]

A new dual-cage-based porous metal-organic framework (MOF, termed DZU-113) assembly from the triazole-carboxylate linker and the Cu(II) paddle-wheel unit was solvothermally constructed. The structure of DZU-113 was determined by single-crystal X-ray diffraction, being consisted of the octahedral cage with an internal diameter of approximately 0.4 ​nm, and the spindle nano-cage with internal pores of about 0.8 ​nm ​× ​2.2 ​nm, respectively. Specially, the uncoordinated N atoms of triazole groups are distributed in the bottleneck windows of the spindle nano-cage, serving as open functional sites. DZU-113 has permanent porosity with the Brunauer−Emmett−Teller surface area of 1207 ​m2 ​g−1. The CO 2 adsorption test demonstrated that the total uptake of DZU-113 can reach 66.7 ​cm3 ​g−1 ​at 298 ​K, and 112.0 ​cm3 ​g−1 ​at 273 ​K, 1 ​bar. Moreover, it achieves robust catalytic performance for the cycloaddition of CO 2 and epoxides under mild conditions. In this paper, a new dual-cage-based porous metal-organic framework (termed DZU-113) assembly from the triazole-carboxylate linker and the Cu(II) paddle-wheel unit was solvothermally constructed, which has good CO 2 adsorption capacity and catalytic performance for the cycloaddition of CO 2 and epoxides under mild conditions, owing to the cage structure and the uncoordinated N atoms in its structure. [Display omitted] • A porous Cu-MOF (DZU-113) featuring octahedral and spindle cages was successfully synthesized. • Uncoordinated N atoms of ligand were distributed in the bottleneck windows of the spindle cage to serve as functional site. • DZU-113 exhibited good CO 2 capture and can catalyze the cycloaddition reaction of CO 2 with epoxides under mild environments. • The relatively high solvents and thermal stability endows the DZU-113 with high reusability. [ABSTRACT FROM AUTHOR]

In recent years, global warming has become an important topic of public concern. As one of the most promising carbon capture technologies, solid amine adsorbents have received a lot of attention because of their high adsorption capacity, excellent selectivity, and low energy cost, which is committed to sustainable development. The preparation methods and support materials can influence the thermal stability and adsorption capacity of solid amine adsorbents. As a supporting material, it needs to meet the requirements of high pore volume and abundant hydroxyl groups. Industrial and biomass waste are expected to be a novel and cheap raw material source, contributing both carbon dioxide capture and waste recycling. The applied range of solid amine adsorbents has been widened from flue gas to biogas and ambient air, which require different research focuses, including strengthening the selectivity of CO 2 to CH 4 or separating CO 2 under the condition of the dilute concentration. Several kinetic or isotherm models have been adopted to describe the adsorption process of solid amine adsorbents, which select the pseudo-first order model, pseudo-second order model, and Langmuir isotherm model most commonly. Besides searching for novel materials from solid waste and widening the applicable gases, developing the dynamic adsorption and three-dimensional models can also be a promising direction to accelerate the development of this technology. The review has combed through the recent development and covered the shortages of previous review papers, expected to promote the industrial application of solid amine adsorbents. [Display omitted] • The review is based on studies about solid amine adsorbents. • The technology of solid amine adsorbents provide a novel solution to global warming. • Waste-derived support materials contribute both carbon dioxide capture and waste recycling. • The application to biogas and ambient air is a promising development direction. • Novel kinetic and isotherm models should be developed to study adsorption process. [ABSTRACT FROM AUTHOR]

Quantifying fossil fuel CO 2 (CO 2 ff) in the atmosphere provides a benchmark method to monitor anthropogenic carbon emissions. Radiocarbon (14C) in atmospheric CO 2 ff has been widely studied using the 14C in plants to document regional CO 2 ff patterns. However, annual CO 2 ff variations, reflecting spatial distributions based on plant samples, are still scarce. In this paper, the spatial distribution and temporal CO 2 ff changes in the Guanzhong Basin is established using Δ14C measurements from maize leaves collected in 2011 and 2012. With regard to spatial distribution, samples collected around Xi'an City showed lower Δ14C values (more CO 2 ff), while sites located near the perimeter of the basin showed higher Δ14C values (less CO 2 ff). This is likely due to the concentration of anthropogenic activities in the center of the Guanzhong Basin. The observed CO 2 ff mole fractions generally matched with PKU CO 2 inventory and the ODIAC CO 2 inventory data in the spatial distribution trend. However, it seems that thermal power plants were not well captured by the PKU CO 2 inventory. Our results provide useful information for the improvement of the inventory and verification of regional carbon cycle models. • The Δ14C in maize leaves for 2011 and 2012 were analyzed in Guanzhong Basin. • Spatial distribution of CO 2 ff mole fractions in Guanzhong Basin were studied. • The spatial pattern of observed CO 2 ff matches with the CO 2 inventory. [ABSTRACT FROM AUTHOR]

Seagrass meadows, through their large capacity to sequester and store organic carbon in their sediments, contribute to mitigate climatic change. However, these ecosystems have experienced large losses and degradation worldwide due to anthropogenic and natural impacts and they are among the most threatened ecosystems on Earth. When a meadow is impacted, the vegetation is partial- or completely lost, and the sediment is exposed to the atmosphere or water column, resulting in the erosion and remineralisation of the carbon stored. This paper addresses the effects of the construction of coastal infrastructures on sediment properties, organic carbon, and total nitrogen stocks of intertidal seagrass meadows, as well as the size of such stocks in relation to meadow establishing time (recently and old established meadows). Three intertidal seagrass meadows impacted by coastal constructions (with 0% seagrass cover at present) and three adjacent non-impacted old-established meadows (with 100% seagrass cover at present) were studied along with an area of bare sediment and two recent-established seagrass meadows. We observed that the non-impacted areas presented 3-fold higher percentage of mud and 1.5 times higher sedimentary organic carbon stock than impacted areas. Although the impacted area was relatively small (0.05–0.07 ha), coastal infrastructures caused a significant reduction of the sedimentary carbon stock, between 1.1 and 2.2 Mg OC, and a total loss of the carbon sequestration capacity of the impacted meadow. We also found that the organic carbon stock and total nitrogen stock of the recent-established meadow were 30% lower than those of the old-established ones, indicating that OC and TN accumulation within the meadows is a continuous process, which has important consequences for conservation and restoration actions. These results contribute to understanding the spatial variability of blue carbon and nitrogen stocks in coastal systems highly impacted by urban development. • Seagrass organic carbon (OC) stock was impacted by coastal infrastructures. • OC stocks at impacted areas were 1.5 times lower than at non-impacted areas. • Non-impacted areas presented 3-fold higher percentage of mud than impacted areas. • Recently established meadow presented 30% lower OC than the old-established ones. [ABSTRACT FROM AUTHOR]

Decarbonizing the cement manufacturing sector presents an interesting and pressing challenge as it is one of the largest energy consumers in industry (i.e., 7%), emitting considerable amounts of anthropogenic carbon dioxide (i.e., 7%). This paper performs a technical and environmental assessment of decarbonisation of cement production through process modelling and simulation, thermal integration analysis, and Life Cycle Assessment (LCA). Integration of three post-combustion capture methods for a conventional cement plant with an annual productivity of one million tons and a carbon capture rate of 90% is evaluated in comparison to the reference case without carbon capture and storage (CCS). Mass and energy balances derived from simulations are used for the assessment of three innovative capture systems: reactive gas-liquid absorption using Methyl-Di-Ethanol-Amine, reactive gas-solid adsorption using calcium looping (CaL) technology and membrane separation. For the LCA study, a "cradle-to-gate" approach is carried out using GaBi software, according to the ReCiPe impact assessment method. The general conclusion is that integrating the CCS methods into the cement production process leads to a decrease in global warming potential (GWP) in the range of 69.91%–76.74%. Of the CCS technologies analysed, CaL technically outperforms the others as it requires 34% less coal and provides 1.6 times higher gross energy efficiency. From an environmental perspective, CaL integration ranks first, with the lowest scores in six of the nine impact categories and a GWP reduction of 76.74% compared to the baseline scenario without CCS. [Display omitted] • Decarbonisation of the cement industry by post-combustion CO 2 capture technologies. • Thermal integration, technical and environmental evaluation were carried out. • Chemical scrubbing and calcium looping are self-sufficient in terms of heat and power. • Calcium looping exhibits better environmental performances than other two cases. [ABSTRACT FROM AUTHOR]

Biochar can achieve multiple benefits including solid waste management, polluted water remediation, carbon sequestration, and emission reduction. However, various environmental factors (such as temperature variations and dry-wet alternation) and microbial activity may lead to the fragmentation, dissolution, and oxidation of biochar. These accelerate the dissolution of biochar-derived dissolved organic matter (DOM) and then influence disinfection byproducts formation potential (DBPFP) throughout the water treatment process. In this paper, biochars from six biomass feedstocks with five aging processes were prepared, and the DBPFP of biochar and its derived DOM were first studied systematically. Different aging processes might increase the DBPFP of biochar by increasing DOM content and changing the fraction distribution of DOM derived from biochar. Especially, the DBPFP of biochar increased apparently with the chemical aging process. Coexisting with the environmental concentration of humic acid, even aged biochar showed the potential to reduce DBPFP and integrated toxic risk value of the mixed system. In this study, the DBPFP of biochar-derived DOM during the disinfection process is confirmed, and the results can give information to the selection of biomass feedstocks of biochar and its service life in the water treatment process. [Display omitted] • Disinfection byproducts formation potential of aged biochar was first evaluated. • DBPFP of biochar influenced by feedstocks and pyrolysis temperature. • ITRV of chemical aged biochar-derived DBPs increased by 100 times. • Even aged biochar can reduce toxicity of simulated raw water during chlorination. [ABSTRACT FROM AUTHOR]

Mineral CO 2 sequestration is a promising process for the reduction of carbon dioxide emissions to the atmosphere. In this paper, alkaline calcium-rich dust particles collected from bag filters of electric arc furnaces (EAF) for steel making were utilized as a viable raw material for mineral CO 2 sequestration. The dust particles were pre-treated through hydration, drying and screening. The pre-treated particles were then subjected to direct gas–solid carbonation reaction in a fluidized-bed reactor. The carbonated products were characterized to determine the overall sequestration capacity and the mineralogical structures. Leaching tests were also performed to measure the extracted minerals from the carbonated dust and evaluate the carbonation process on dust stabilization. The experimental results indicated that CO 2 could be sequestered using the pre-treated bag house dust. The maximum sequestration of CO 2 was 0.657 kg/kg of dust, based on the total calcium content. The highest degree of carbonation achieved was 42.5% and the carbonation efficiency was 69% at room temperature. [ABSTRACT FROM AUTHOR]

Sub-Saharan Africa (SSA) experiences soil degradation, food and livelihood insecurity, environmental pollution and lack of access to energy. Biochar has gained international research attention, but few studies have investigated the potential of biochar to address the challenges in SSA. This paper seeks to identify and evaluate generic potential opportunities and constraints associated with biochar application in sub-Saharan Africa using Zimbabwe as case study. Specific objectives were to; (1) identify and quantify feedstocks for biochar production; (2) review literature on the biochar properties, and evaluate its potential applications in agriculture, environmental remediation and energy provision, and (3) identify research gaps, risks and constraints associated with biochar technology. Biochar feedstocks in Zimbabwe were estimated to be 9.9 Mton yr −1 , predominantly derived from manure (88%) and firewood (10%). This will yield 3.5, 1.7 and 3.1 Mton yr −1 of biochar, bio-oil and synthetic gas, respectively. Land application of the 3.5 Mton yr −1 of biochar (≈63% C) would sequester approximately 2.2 Mton yr −1 of soil carbon in Zimbabwe alone, while simultaneously minimizing the environmental and public health risks, and greenhouse gas emissions associated with solid organic wastes. Biochar potentially enhances soil and crop productivity through enhanced nutrient and soil moisture availability, amelioration of acidic soils and stimulation of microbial diversity and activity. Due to its excellent adsorption properties, biochar has potential applications in industrial and environmental applications including water and wastewater treatment, remediation and revegetation of contaminated soils and water. Biochar products have energy values comparable or higher than those of traditional biomass fuels; thereby making them ideal alternative sources of energy especially for poor households without access to electricity. Before the benefits of biochar can be realized in SSA, there is need to overcome multiple risks and constraints such as lack of finance, socio-economic constraints including negative perceptions and attitudes among both researchers and consumers, and environmental and public health risks. Therefore, there is need to conduct fundamental research to demonstrate the benefits of biochar applications, and develop policy framework and criteria for its production and subsequent adoption. [ABSTRACT FROM AUTHOR]

When assessing soil organic carbon (SOC) sequestration and its climate change (CC) mitigation potential at global scale, the dynamic nature of soil carbon storage and interventions to foster it should be taken into account. Firstly, adoption of SOC-sequestration measures will take time, and reasonably such schemes could only be implemented gradually at large-scale. Secondly, if soils are managed as carbon sinks, then SOC will increase only over a limited time, up to the point when a new SOC equilibrium is reached. This paper combines these two processes and predicts potential SOC sequestration dynamics in agricultural land at global scale and the corresponding CC mitigation potential. Assuming that global governments would agree on a worldwide effort to gradually change land use practices towards turning agricultural soils into carbon sinks starting 2014, the projected 87-year (2014-2100) global SOC sequestration potential of agricultural land ranged between 31 and 64 Gt. This is equal to 1.9-3.9% of the SRES-A2 projected 87-year anthropogenic emissions. SOC sequestration would peak 2032-33, at that time reaching 4.3-8.9% of the projected annual SRES-A2 emission. About 30 years later the sequestration rate would have reduced by half. Thus, SOC sequestration is not a C wedge that could contribute increasingly to mitigating CC. Rather, the mitigation potential is limited, contributing very little to solving the climate problem of the coming decades. However, we deliberately did not elaborate on the importance of maintaining or increasing SOC for sustaining soil health, agro-ecosystem functioning and productivity; an issue of global significance that deserves proper consideration irrespectively of any potential additional sequestration of SOC. [ABSTRACT FROM AUTHOR]

Although there are some review papers on carbon capture, utilization and storage (CCUS), hardly any of these reviews are focused on the role of CO 2 enhanced oil recovery (EOR) in accelerating carbon neutrality in China. In this review, strategies to achieve carbon neutrality is briefly but critically discussed, followed by a review of CO 2 -EOR as a promising technology. Especially, data analysis, including the number of publications on China's carbon neutrality, per capita CO 2 emissions, China's power generation, and the crude oil production of China's large oilfields, is carried out to make the discussion more comprehensive. Given the large amount of coal consumed in China, the high percent of electricity generated with coal, and the slow penetration of renewables already observed, it seems unlikely that 2060 targets will be met without CCUS. In order to achieve carbon neutrality, both reduction in carbon emissions and increase in carbon sequestration are inevitable. Furthermore, it is concluded that CO 2 storage through EOR is likely to have a bright future. However, there are some critical issues to be solved, including the technical issues, leakage and safety issues, cost issues, policy issues, etc. In order to turn CO 2 -EOR into a reliable and more favorable technology, more research and efforts are needed to solve these issues, including advancing carbon capture technologies, improving storage technologies, developing effective monitoring technologies, deploying government support and incentive policies, etc. • CO 2 emission reduction and sequestration are needed to achieve carbon neutrality. • Carbon capture and storage without utilization is not suitable for China. • CO 2 -enhanced oil recovery (EOR) is more viable as a cost-effective CCUS technology. • CO 2 -EOR is likely to make great contributions to China's carbon neutrality target. • CO 2 leakage risk exists and more research is needed to ensure CO 2 is safely stored. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO 2) emissions from fossil fuel combustion have been linked to increased average global temperatures, a global challenge for many decades. Mitigating CO 2 concentration in the atmosphere is a priority for the protection of the environment. This is a comparison of the three main technological categories available for CO 2 capture and storage. They include: oxy-fuel combustion, pre-combustion, and post-combustion. Each capture technology has inherent benefits and disadvantages in cost, implementation, and flexibility, but post-combustion CO 2 capture has demonstrated the most promising results in typical power plant configurations. This paper presents a review of different post-combustion CO 2 capture materials; solvents, membranes, and adsorbents, focusing on economical and environmentally safe low to high temperature solid adsorbents. Furthermore, the authors summarize the advantages and limitations of the materials investigated to provide insight into the challenges and opportunities currently facing the development of post-combustion CO 2 capture technologies. The solid sorbents currently available for CO 2 capture are also reviewed in detail, including physical and chemical properties, reactions, and current research efforts on improvement. [Display omitted] • Emerging trends in post-combustion CO 2 capture are introduced and compared. • Recent advances in solid sorbents for post-combustion CO 2 capture is investigated and summarized. • New development in solid adsorbents and factors that affect treatment performance. • Review of economics, environmental analysis and policy in post-combustion CO 2 capture. [ABSTRACT FROM AUTHOR]

The economic and technical feasibility of carbon capture and sequestration (CCS) systems are gaining importance as CO2 emission reduction is becoming a more pressing issue for parties from production sectors. Public and private entities have to comply with national schemes imposing tighter limits on their emission allowances. Often these parties face two options as whether to invest in CCS or buy carbon credits for the excess emissions above their limits. CCS is an expensive system to invest in and to operate. Therefore, its feasibility depends on the carbon credit prices prevailing in the markets now and in the future. In this paper we consider the problem of installing a CCS unit in order to ensure that the amount of CO2 emissions is within its allowable limits. We formulate this problem as a non-linear optimisation problem where the objective is to maximise the net returns from pursuing an optimal mix of the two options described above. General Algebraic Modelling Systems (GAMS) software was used to solve the model. The results were found to be sensitive to carbon credit prices and the discount rate, which determines the choices with respect to the future and the present. The model was applied to a methanol synthesis plant as an example. However, the formulation can easily be extended to any production process if the CO2 emissions level per unit of physical production is known. The results showed that for CCS to be feasible, carbon credit prices must be above 15 Euros per ton. This value, naturally, depends on the plant-specific data, and the costs we have employed for CCS. The actual prices (≈5 Euros/ton CO2) at present are far from encouraging the investors into CCS technology. [Copyright &y& Elsevier]

Abstract: Our goal was to move toward full economic valuation of fuels-reduction treatments applied to ponderosa pine (Pinus ponderosa) forests. For each of five fuels-reduction projects in northern Arizona, we calculated the economic value of carbon storage and carbon releases over one century produced by two fuels-reduction treatments of thinning following by prescribed burning every one (Rx10) or two (Rx20) decades and for no treatment followed by intense wildfire once in the first 50 years (HF50) or once in the first 100 years (HF100). Our estimates include two uses of harvested wood, the current use as pallets, and multiproduct use as paper, pallets, and construction materials. Additionally, we included the economic value of damage and loss from wildfire. Results indicate that treatments increase carbon stock in live trees over time; however, the inclusion of carbon emissions from treatments reduces net carbon storage and thereby carbon credits and revenue. The economic valuation shows that the highest net benefit of $5029.74 ha−1 occurs for the Rx20 treatment with the HF50 baseline and the high estimated treatment benefits of avoided losses, regional economic benefits, and community value of fire risk reduction. The lowest net benefit of −$3458.02 ha−1 occurs for the Rx10 treatment with the HF100 baseline and the low estimated treatment benefits. We conclude that current nonmarket values such as avoided wildfire damage should be included with values of traditional wood products and emerging values of carbon storage to more appropriately estimate long-term benefits and costs of forest fuels-reduction treatments. [Copyright &y& Elsevier]

Abstract: The phase equilibrium of ocean carbon dioxide hydrate should be understood for ocean storage of carbon dioxide. In this paper, the isochoric multi-step heating dissociation method was employed to investigate the phase equilibrium of carbon dioxide hydrate in a variety of systems (NaCl solution, submarine pore water, silica sand+NaCl solution mixture). The experimental results show that the depression in the phase equilibrium temperature of carbon dioxide hydrate in NaCl solution is caused mainly by Cl− ion. The relationship between the equilibrium temperature and freezing point in NaCl solution was discussed. The phase equilibrium temperature of carbon dioxide hydrate in submarine pore water is shifted by −1.1K to lower temperature region than that in pure water. However, the phase equilibrium temperature of carbon dioxide hydrate in mixture samples of coarsed-grained silica sand and NaCl solution is in agreement with that in NaCl solution with corresponding concentrations. The relationship between the equilibrium temperature and freezing point in mixture samples was also discussed. [Copyright &y& Elsevier]

The present paper investigates the various features of NaOH aqueous solution when applied as an absorbent to capture carbon dioxide (CO2) emitted with relatively high concentration in the flue gas. The overall CO2 absorption reaction was carried out according to consecutive reaction steps that are generated in the order of Na2CO3 and NaHCO3. The reaction rate and capture efficiency were strongly dependent on the NaOH concentration in the Na2CO3 production range, but were constant in the NaHCO3 production step, irrespective of the NaOH concentration. The amount of CO2 absorbed in the solution was slightly less than the theoretical value, which was ascribed to the low trona production during the reaction and the consequent decrease in CO2 absorption in the NaOH solution. The mass ratio of absorbed CO2 that participated in the Na2CO3, NaHCO3, and trona production reactions was calculated to be 20:17:1, respectively. [Copyright &y& Elsevier]

In this paper we present an estimate of the economic value of carbon sequestration in olive grove soils derived from the implementation of different agricultural management systems. Carbon sequestration is considered jointly with other environmental co-benefits, such as enhanced erosion prevention and increased biodiversity. The estimates have been obtained using choice experiments and show that there is a significant demand from society for these environmental services. From a policy perspective, an agri-environmental scheme that delivers the highest level of each environmental service would be valued by society at 121 Euros per hectare. If we focus on carbon sequestration, each ton of CO2 would be valued at 17 Euros. These results show that there is scope to include agricultural soil carbon sequestration in climate change mitigation strategies and to provide guidance for setting payments for agri-environmental schemes promoting soil management changes. [Copyright &y& Elsevier]