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Composite materials have been widely used because of their superior properties compared to those of the original material. Separation of the constituent materials is not easy in the recycling process, and such an effort lowers economic viability. As such, this study employed a pyrolysis as a valorizing method for the composite material. Disposable paper cup waste (DPCW) was chosen as the model compound for paper-plastic composites. To offer green/sustainable features, CO2 was employed as a raw and reactive material in the pyrolysis process. It was proved that DPCW primarily composed of cellulose (outer layer) and polyethylene (inner layer). In the single-stage and multistage pyrolysis of DPCW, the CO2 reactivity in the homogeneous reaction of CO2 and DPCW-derived volatiles was not rapid. To accelerate the reaction kinetics governing the reactivity of CO2, the catalytic pyrolysis of DPCW over Ni/SiO2 was performed. The formation of syngas increases significantly, suggesting that CO2 reactivity was catalytically enhanced. The generation of syngas (enhanced by CO2) was inversely related to the DPCW oil generation, indicating that more carbon was assigned from the oil to the gaseous pyrogenic products. The study results would offer a strategic means to valorize paper-plastic composites and CO2 into energy through pyrolysis. [ABSTRACT FROM AUTHOR]

The case studies are introduced in this study, highlighting freight transportation via road and road rail between satellite cities in Pakistan's Punjab and Sindh provinces. The case study analysis contributes to developing environmentally friendly and cost-effective transportation solutions and reducing nitrous oxide (N2O) and carbon dioxide (CO2) emissions associated with road and intermodal freight transit. We developed a mixed-integer linear programming (MILP) model to formulate the bi-objective problem, including real-life constraints, emissions at starting nodes, ending notes, and between the arc. In the mathematical model, the cost and emissions functions are developed to minimize the primary and secondary objective functions in the road and intermodal transportation. Furthermore, five distinct sets (locations, starting stations, ending stations, transport orders, and transport service) with parameters relating to container movement between the starting and ending nodes are a necessary part of the MILP formulation. The multiobjective optimization problem is solved by metaheuristic techniques such as the multiobjective genetic algorithm as the goal of applying a metaheuristic algorithm is to find the search space to search the near to optimized solutions. The Pareto front solutions are provided for balancing the costs and emissions of transporting supplies from Punjab to Sindh using the MATLAB solver toolbox. We gathered data from one of Pakistan's most well-known logistics service providers in the paper industry. According to the findings, intermodal transportation is 72% more cost-effective than road transportation. Additionally, by substituting intermodal transportation for road transportation, N2O, and CO2 emissions can be reduced by 74% and 57%, respectively. [ABSTRACT FROM AUTHOR]

The urgent need to address global carbon emissions and promote sustainable energy solutions has led to a growing interest in carbon dioxide (CO2) conversion technologies. Among these, the transformation of CO2 into methanol (MeOH) has gained prominence as an effective mitigation strategy. This review paper provides a comprehensive exploration of recent advances and applications in the direct utilization of CO2 for the synthesis of MeOH, encompassing various aspects from catalysts to market analysis, environmental impact, and future prospects. We begin by introducing the current state of CO2 mitigation strategies, highlighting the significance of carbon recycling through MeOH production. The paper delves into the chemistry and technology behind the conversion of CO2 into MeOH, encompassing key themes such as feedstock selection, material and energy supply, and the various conversion processes, including chemical, electrochemical, photochemical, and photoelectrochemical pathways. An in-depth analysis of heterogeneous and homogeneous catalysts for MeOH synthesis is provided, shedding light on the advantages and drawbacks of each. Furthermore, we explore diverse routes for CO2 hydrogenation into MeOH, emphasizing the technological advances and production processes associated with this sustainable transformation. As MeOH holds a pivotal role in a wide range of chemical applications and emerges as a promising transportation fuel, the paper explores its various chemical uses, transportation, storage, and distribution, as well as the evolving MeOH market. The environmental and energy implications of CO2 conversion to MeOH are discussed, including a thermodynamic analysis of the process and cost and energy evaluations for large-scale catalytic hydrogenation. [ABSTRACT FROM AUTHOR]

Near miscibility widely exists in carbon dioxide (CO2) injection development projects. However, there is no existing approach to quantify the effect of near miscibility on oil recovery. In this paper, slim tube experiments were conducted to study near miscible region. The oil displacement efficiency curve is divided into immiscibility, near miscibility and miscibility. And three linear function is obtained, respectively. Then, the space between production well and CO2 injection well is discrete to characterize the effect of near miscibility on oil recovery. Then, a new approach is proposed to calculate oil recovery of CO2 displacement in tight oil reservoirs. This approach can calculate oil recovery considering near miscibility. It is found that minimum miscibility pressure (MMP) without considering near miscibility is 4 MPa lower than considering near miscibility. The near miscible pressure range is from 0.77 times to 1 time MMP considering near miscibility. Oil displacement efficiency difference reaches to be the maximum when the pressure is the minimum miscibility pressure without considering near miscibility. The maximum of the oil displacement efficiency difference is 3.4%. The optimal formation pressure considering near miscibility is 5 MPa larger than that without considering near miscibility. The oil recovery considering near miscibility is from 0.9 to 1.3% lower than that not considering near miscibility. It reaches to be the maximum when the pressure is the optimal formation pressure level without considering near miscibility. The maximum of the oil recovery difference is 1.3%. [ABSTRACT FROM AUTHOR]

Utilizing carbon dioxide in chemical processes is one of the suggested remedies for reducing its atmospheric concentration. In this paper, the simulation of the propylene carbonate production process using 1,2-propanediol and carbon dioxide has been performed. The impact of temperature was examined between 75 and 400°C. It has been found that as temperature rises, reaction conversion increases. Additionally, the impact of recycling ratio was examined in the range of 0.1–0.5, which demonstrates that a rise in the recycle ratio results in a fall in conversion. Furthermore; it was observed that the pressure initially increases the solubility of carbon dioxide in 1,2-propanediol and improves the conversion of the reaction, but when enough carbon dioxide is supplied in the reaction, increasing the pressure does not affect the corresponding reaction. The effect of all studied parameters depends on the residence time of the reactants in the reactor. Investigating the interaction of parameters and optimizing the process has shown several optimal point of the process such as temperature of 295 °C, a recycle ratio 0.1, feed ratio 0.8 and a residence time of 12.61 h, with the related conversion being 59.6%. [ABSTRACT FROM AUTHOR]

In the global ecosystem, wetlands are vital carbon sinks, playing a crucial role in absorbing greenhouse gases such as carbon dioxide and mitigating global warming. Accurate estimation of wetland carbon content is essential for research on wetland carbon sinks. However, the carbon cycle of wetlands is complex, and the carbon sinking of wetlands is affected by climate, topography, water level conditions, vegetation types, soil types, and other factors. This has caused significant challenges in the estimation of wetland carbon sinks. In current studies, most research has focused on the impact of individual factors on wetland carbon sinks, often ignoring the interaction between various factors, which further leads to uncertainty in wetland carbon measurements. This paper aims to elucidate the process of the wetland carbon cycle, summarize the factors affecting wetland carbon sinks, and explore the interplay between various factors and their influence on wetland carbon sinks, aiming to provide theoretical support for the study of wetland carbon sinks. Additionally, this paper reviews the advantages and disadvantages of current wetland carbon measurement methods, proposes research directions for combining machine learning methods, identifies existing difficulties in current wetland carbon measurement, and offers suggestions to serve as a reference for future wetland carbon sink estimation and wetland management.Highlights: The potential and significance of wetland carbon sinks are explained. The advantages and disadvantages of current wetland carbon measurement techniques are summarized. The prospective method for integrating machine learning into integrated wetland carbon measurement is proposed. [ABSTRACT FROM AUTHOR]

The adverse effects of climate change calls for the rapid transformation of manufacturing processes to decrease the emissions of carbon dioxide. In particular, a lower carbon footprint can be achieved by capturing carbon dioxide at the site of emission. Here we review the use of industrial effluents, waste and residues to capture carbon dioxide. Waste include steelmaking slag, municipal solid waste incinerator ashes, combustion fly ash, black liquor, paper mill waste, mining waste, cement waste, construction and demolition waste, waste from the organic industry, and flue gas desulfurization gypsum waste. Capture capacities range from 2 to 800 kg of carbon dioxide per ton of waste, depending on processes, waste type and conditions. Cement waste and flue gas desulfurization gypsum waste show the highest capture capacity per ton of waste. [ABSTRACT FROM AUTHOR]

This paper investigates whether carbon dioxide (CO2) intensity of gross domestic product (GDP) matters for environmental deregulations in Southern European countries over the period of 1990–2018 while controlling economic growth, globalization, and energy consumption. The present study uses the second generation panel based techniques, namely cross-sectional dependency test, cross-sectional unit-root test, Westerlund cointegration test, augmented mean group and common correlated effects mean group estimators, and Dumitrescu–Hurlin causality test to measure the effect of CO2 intensity of GDP, economic growth, globalization, and energy consumption on environmental degradation. The empirical finding of the present study reveals that the CO2 intensity of GDP is an important factor in determining environmental degradation in South European countries, as the outcomes show that a 1% boost in CO2 intensity of GDP is causing a 1.7728% increase in CO2 emissions. Moreover, a 1% increase in economic growth caused a 0.2568% boost in CO2 emissions. The result is crucial for policy decision-making and can perhaps be applied to take decisive policy actions to mitigate environmental issues. [ABSTRACT FROM AUTHOR]

Accurate estimation of CO2-brine Interfacial Tension (IFT) is of great importance since it is required to model the residual/capillary trapping of CO2 in geological formations. In this paper, a novel correlation is proposed based on the classical orthogonal polynomials to estimate the CO2-brine IFT of monovalent salts with common anion. To do so, CO2-brine IFT samples composed of samples from the literature and experimentally measured values using an in-house high-pressure high-temperature IFT measurement device were collected within a wide range of temperatures, pressures, and salinities. The utilized brines included NaCl and KCl salts. Then, a predictive model was developed based on the Group Method of Data Handling approach as a function of temperature, pressure, and ionic strength. The proposed method was compared with four methods from the literature in terms of average absolute percentage error (AAPE), coefficient of determination R 2 , histograms of error, and percent error plots. Results showed the superiority of the proposed method over other methods with an AAPE of 9.85 and R 2 of 0.719. Also, it was shown that the proposed method did not produce too large errors, contrary to other methods. Therefore, the proposed method can be used reliably as a tool for CO2-brine IFT estimation in CO2 storage projects. [ABSTRACT FROM AUTHOR]

One of the possible sources of carbon dioxide emission into the atmosphere can be river ecosystems. The paper presents the results of measuring CO2 fluxes from the surface of several rivers and lakes in Tomsk Region. In the experimental period, average carbon dioxide fluxes were 143.7 ± 21.7 (August 13–14, 2023), 53.3 ± 21.2 (August 19), and 80.4 ± 59.9 mgC m−2 h−1 for the Ob River; 66.1 ± 17.3 mgC m−2 h−1 for the Ket River; 33.3 ± 17.3 mgC m−2 h−1 for the swamp Karasevoye Lake, 50.2 ± 23.0 mgC m−2 h−1 for the Suiga River, and 81.9 ± 11.5 mgC m−2 h−1 for the Iksa River. The flux magnitudes significantly depended not only on the object of the study, but also on hydrometeorological conditions. [ABSTRACT FROM AUTHOR]

Catalytic synthesis of urea is a bright substitutable to Haber–Bosch progression and industrial urea synthesis. Electrochemical C–N coupling of carbon dioxide and nitrogen oxides under environmental conditions is a newly developed method, which also provides a novel opinion for solving nitrate contamination. Conjugated organic frameworks (COFs) have been used as prospective electrocatalysts for nitrogen reduction reactions and carbon dioxide reduction reactions (CO2RR) as a result of their regulate structure and multihole properties, resulting in efficient electron transfer. This paper reports the efficient synthesis of urea from carbon dioxide and nitrate over MoM1S-Pc-M2PPs COF (M as a transition metal) electrocatalyst. According to the calculation of DFT, it was found that it was difficult for carbon dioxide and nitrogen oxide to coadsorb on MoM1S-Pc to synthesize urea, so we chose to synthesize CO on the metal porphyrin (M2PPs) structural unit, and then overflow on the bimetallic phthalocyanine and nitrogen oxide to synthesize urea. The possibility of nitrate adsorption on different catalysts was verified by calculation. We screened the stability, nitrate adsorption strength, and catalytic activity of MoM1S-Pc candidates, and the results showed that the most promising candidate catalyst was MoFeS-Pc. At the same time, the CO2RR M2PPs substrate was also screened, and the VPPs structure was selected as the best. In the study of coupling between different nitrogen-containing intermediates and *CO, the C–N coupling mechanism shows that *NOH and *CO are two possible C–N coupling nitrogen intermediates, which are shown to be thermodynamically spontaneous and have an inferior activation barrier. This study not only provisions novel perceptions into urea synthesis by coupling nitrogen oxides with carbon dioxide under environmental conditions, but also paves the way for boosting the sustainable production of carbon and nitrogen-coupled products. [ABSTRACT FROM AUTHOR]

This paper evaluated ZnO, SiO2 and zeolite 13X for removing CO2 from normal heptane (nC7) as synthetic gas condensates in batch mode. Based on the results of CO2 adsorption isotherms, zeolite 13X had the highest CO2 uptake in 1400–3700 ppm at atmospheric pressure. Due to the higher specific surface area of granular zeolite 13X, its CO2 uptake was more than that of zeolite 13X powder. Also, the CO2 adsorption equilibrium time was less than 30 min for zeolite 13X powder. The selectivity of zeolite 13X powder (i.e., H2S/CO2) was 2.36–4.08 for 2001–3930 ppm H2S with 1668 ppm CO2. Besides, the CO2 breakthrough time for zeolite 13X powder was 50–4 min for WHSV (weight hourly space velocity) = 5–20 h−1 at 30 bar in continuous mode. Additionally, for the increased CO2 concentration from 1000 to 3000 ppm, the CO2 breakthrough time decreased from 30 to 11 min with WHSV = 10 h−1. The CO2 breakthrough time diminished by 2.5-fold as the pressure was reduced from 30 bar to atmosphere for the initial CO2 concentration of 1000 ppm in nC7 and WHSV = 10 h−1. Subsequently, the regeneration of zeolite 13X by stagnant hot air was investigated for the CO2 concentration range of 1000–3000 ppm, air-adsorbent contact time range of 30–180 min and temperature range of 100–300 °C using Box–Behnken design. Its regeneration efficiency was more than 95% for the CO2 concentration below 1000 ppm. [ABSTRACT FROM AUTHOR]

In order to study the cruise safety of aircraft under high altitude and low pressure, the combustion characteristics of protective cover and insulation layer of waxy aviation cable FXL under normal pressure and low pressure are studied in this paper. The minimum ignition time (TTI), the maximum radiation temperature, the flue gas density and the mass loss rate of the protective cover and insulation layer of the waxy FXL aviation cable under 96 kPa and 61 kPa were studied. It is found that the minimum radiation temperature and TTI of the cable at 61 kPa are slightly higher than those at 96 kPa, but the activation energy is basically not affected by the air pressure. The smoke density and smoke composition under 96 kPa and 61 kPa were further studied, and it was found that the smoke density of the cable under 61 kPa sheath and insulation layer was lower than that under 96 kPa. The oxygen, carbon dioxide and carbon monoxide components in the flue gas were studied. It was found that the O2 concentration of 96 kPa and 61 kPa cable protective sleeve and insulation layer decreased steadily at first and then increased. The change trend of CO2 concentration was opposite, and the CO concentration showed a double-peak phenomenon. In addition, the mass loss rate (MLR) at different O2 concentrations increases linearly with the increase in O2 concentration. This work helps to understand the difference of combustion characteristics between 96 and 61 kPa, and provides a reference for improving civil aviation safety performance. [ABSTRACT FROM AUTHOR]

Mars has nearly ideal conditions for CO2 dissociation by glow discharge plasmas. The directly generation of O2 and CO on Mars was considered to be feasible and practical for in situ resource utilization of Martian atmosphere to get respirable O2 and fuel. In this paper, we conduct several experiments under simulated Martian conditions to investigate the process and how the key parameters effect the generation of O2 and CO in CO2 glow discharge reactions. The yields of new products (i.e., O2 and CO) under various gas discharge work parameters (i.e., discharge power, frequency, voltage, gap between the discharge plane electrodes and gas pressure) were systematically investigated. The reaction mechanism and reaction path of CO2 glow discharge has been discussed. In our study the max yield of O2 by CO2 discharge dissociation was got about 21.8 g/h at 168 W which is very close to that of NASA MOXIE (Mars Oxygen In-Situ Resource Utilization Experiment) at the same power. Our results showed the great potentiality of glow discharge for the practicable technology of O2 and CO generation for in-situ resource utilization on Mars. [ABSTRACT FROM AUTHOR]

Poly(butylene adipate-co-terephthalate) (PBAT) foam is regarded as one of the ideal alternatives to petroleum-based polymer foams in view of its advantages of lightweight, high elasticity, biodegradability and biocompatibility, while the problem of shrinkage after foaming has seriously limited its application in industry. In this paper, the no-shrinkage chain-extend PBAT-glycerin monostearate (GMS) foams with ultra-high volume expansion ratio (VER) were prepared by scCO2-assisted molten foaming method. The chain extension reaction between PBAT and chain extender (CE) were investigated by torque curves, gel fraction and FTIR measurements. Comparing with torqued PBAT, the storage modulus of CE-PBAT2 specimen increased 3 orders of magnitude and their crystallization temperature rose from 72.5 to 87.2 ℃. Furthermore, the addition of GMS was beneficial to enhance the dimensional stability of CE-PBAT foams. When 2 phr CE and 2.5 phr GMS were incorporated into PBAT, CEPBAT-GMS2.5 foam attained ultra-high VER of 25.38 times, resilience ratio of 87% with no-shrinkage, which revealed admirable compression and resilience properties. In conclusion, this study provided a feasible new method for improving the VER and dimensional stability of PBAT foams. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new extension of the Vasicek model to the multivariate case and analyze its characteristics, including its probability density function, marginal trends, and correlation functions. We also conduct statistical estimation on the model, including likelihood parameter estimation and estimation of the marginal trend and correlation functions. To validate the effectiveness of our proposed model, we use simulation studies and examine the goodness of fit. Additionally, we apply our model to a bivariate case involving the analysis of CO 2 and N 2 O concentrations. We describe the data, fit the bivariate Vasicek stochastic diffusion model, and compare it with the univariate case. Finally, we summarize our findings and discuss the potential applications of our proposed model. [ABSTRACT FROM AUTHOR]

Reducing the use of fossil fuels is critical to human society. In recent years, electrocatalytic carbon dioxide (CO2) reduction has attracted widespread attention. A suitable CO2 reduction catalyst is essential to convert CO2 into more valuable chemical products with high selectivity and efficiency. In this paper, a highly selective ZnAlCe-Ternary metal hydroxides (ZnAlCe-THs) nanocomposite electrocatalyst material was designed and prepared, and its performance as an electrocatalyst for catalytic reduction of CO2 to carbon monoxide (CO) was explored. The layered structure of ZnAlCe-THs nanocomposites facilitates electron transfer as well as CO2 and proton transfer, providing a high specific surface area for the electroactive sites of the electrocatalytic reduction reaction. At the same time, the ZnAlCe-THs catalyst generates CO at an overpotential of − 0.5 V. At − 1.2 V versus the reversible hydrogen electrode (vs. RHE), the bias current density is about 10.46 mA cm−2 with high selectivity of 89.3% Faraday efficiency. Its excellent electrochemical properties make it a good catalyst for the selective reduction of CO2 to CO. In this paper, ZnAlCe-Ternary mental hydroxides (ZnAlCe-THs) with a layered hydrotalclike structure were prepared by hydrothermal and co-precipitation methods. It showed excellent catalytic performance in the electrocatalytic reduction of carbon dioxide to carbon monoxide with a Faraday efficiency of 89.3% at − 1.2 V vs. RHE and a current density of 10.46 mA cm−2 for higher selectivity for CO. In addition, the ZnAlCe-THs catalyst is stable and it can operate for 5 h without particularly significant deactivation. [ABSTRACT FROM AUTHOR]

The freight sector in Australia has been growing at an ever-increasing rate due to domestic and international demand for goods, commodities, and resources. Increased volume of traffic comes with increased greenhouse gas. Greenhouse gas impacts climate change and air pollution, increasing the risk of public health and safety. The European Union used Marco Polo to shift transit freight from road to sea, rail, and inland waterways to reduce the number of trucks on the road to lessen congestion, less pollution, and more reliable and efficient transport of goods. Fuel Tax Credit was similarly introduced in Australia to address some of these issues. It is now time to analyse the impact of these schemes. This paper is a systematic literature review using the Mixed Method Appraisal Tool and Critical Appraisal Skills Programme. Findings include using alternative modes of transport for long distances reduces carbon dioxide and the likelihood of using renewable fuels like electric and hydrogen fuel for trucks. However, research was limited on renewable fuels. [ABSTRACT FROM AUTHOR]

This paper presents a critical review of laser pyrolysis. Although this technology is almost 60 years old, in literature many researchers, both from academia and industry, are still developing and improving it. On the contrary industrial applications are struggling to take off, if not in very restricted areas, although the technology has undoubted advantages that justify future development. The aim of this work consists in analysing a representative pool of scientific papers (230) and patents (121), from the last 20 years, to have an overview about the evolution of the method and try to understand the efforts spent to improve this technology effectively in academia and in industry. This study is important to provide a complete review about the argument, still missing in the literature. The objective is to provide an overview sufficiently broad and representative in the sources and to capture all the main ways in which laser pyrolysis has been used and with what distribution. The main focuses of the study are the analyses of the functions carried out by laser technologies, the application fields, and the types of used laser (i.e. models, power and fluence). Among the main results, the study showed that the main use of laser pyrolysis is to produce nanoparticles and coatings, the main materials worked by laser pyrolysis are silicon and carbon dioxide and the main searched properties in the products of laser pyrolysis are catalysts activity and electrical conductivity. CO2 lasers are the most used and the have high versatility compared to others. In conclusion, the study showed that laser pyrolysis is a consolidated technology within its main application fields (nanoparticles and coatings) for several years. Within this context, the technology has been developed on very different sizes and processes, obtaining a very wide range of results. Finally, these results may also have stimulated new areas of experimentation that emerged mainly in recent years and which concern biomedical applications, additive manufacturing, and waste disposal. [ABSTRACT FROM AUTHOR]

ZnZrOx has been used in large quantities for the preparation of light olefins from CO2, but the relationship between structure and performance remains unclear at present. In this paper, ZnZrOx were prepared by co-precipitation method, and a series of oxides with different sizes were prepared by varying the calcination temperatures. Subsequently, these oxides were combined with SAPO-34 to create a composite bifunctional catalyst for the synthesis of light olefins by CO2 hydrogenation, in which the impact of nanocrystal size effect was examined. The catalytic performance significantly increased as the nanocrystal size reduced from 18 to 12 nm. However, when the nanocrystal size was further decreased to 8 nm, the catalytic performance decline. Characterizations revealed a gradual increase in the number of oxygen vacancies with decreasing nanocrystal size. However, the oxide with the smallest nanocrystal size, prepared by varied calcination temperatures, did not yield the optimal catalytic performance due to sintering occurring during the reaction process. The results show that the assumption that smaller nanocrystal sizes inherently equate to improved catalytic performance is not universally valid, and stability must be considered when the nanocrystal size is decreased. The bifunctional catalysts used in this paper for the prepared light olefins from CO2 in yield as high as 13.8%, which is higher than most previous reports. [ABSTRACT FROM AUTHOR]

A paper-based electrochemical dual-function biosensor capable of determining pH and TCO2 was synthesized for the first time using an iridium oxide pH electrode and an all-solid-state ion electrode (ASIE). In the study, to obtain highly reliable results, the biosensor was equipped with a real-time pH correction function before TCO2 measurements. Compared to traditional liquid-filling carbon dioxide detection sensors, the utilization of ferrocene endows our novel sensor with abundant positive sites, and thus greatly improves its performance. Conversely, the introduction of MXene with conductivity close to that of metals reduces electrode resistance, which is beneficial for accelerating the electrochemical reaction of the sensor and reducing LOD. After optimization, the detection range of TCO2 is 0.095 nM–0.66 M, with a detection limit of as low as 0.023 nM. In addition, the sensor was used in real serum sample-spiked recovery experiments and comparison experiments with existing clinical blood gas analyzers, which confirmed the effectiveness of its clinical application. This study provides a method for the rational design of paper-based electrochemical biosensors and a new approach for the clinical detection of blood carbon dioxide. [ABSTRACT FROM AUTHOR]

Agriculture has a main impact on increasing the economy of most developing countries, and energy policies in fighting climate change have a vital role in strengthening economic growth. This paper studies the impact of agriculture, trade openness and green energy on CO2 emissions in Rwanda during 1990–2022. Phillips- Peron and Augmented Dickey fuller unit root test affirmed the stationary of data, and autoregressive distributed lag (ARDL)-bound testing confirmed a long-run relationship among variables. The study employed an ARDL approach. Findings from long-run elasticities showed that 1% increase in agriculture productivity increased carbon dioxide emissions by 1.94%; 1% increase in trade openness increased carbon dioxide emissions by 0.16%; whereas 1% increase in renewable energy consumption and GDP per capita decreased carbon dioxide emissions by 2.71% and 2%, respectively. The result confirmed the induced environment curve and the pollution haven hypothesis in Rwanda. Moreover, green energy consumption and GDP per capita decreases CO2 emissions eventually, which supports the validity of environment Kuznets curve in Rwanda. The findings recommend that an increase in renewable energy usage and trade reforms accompanied by strong environmental policies to reduce CO2 emissions will develop the agriculture sector and regional economy. Highlights: • Rapid emission reduction is essential for achieving sustainable growth in Rwanda. • An Auto regressive distributed lag approach was employed by using time series data. • The results added new insights on renewable energy, agriculture, trade openness, and CO2 emission in Rwanda. • This article offers policy suggestions to reduce carbon dioxide emissions. [ABSTRACT FROM AUTHOR]

This paper studied some equilibria in the Nd3+–water–nitric acid–TODGA (N,N,N,N-tetraoctyl diglycolamide)–CO2 system and the efficiency of extraction of Nd3+ ions from aqueous solutions into the supercritical (SC) CO2 phase at 313–353 K and 18.0–40.0 MPa. It was shown that, in the absence of TODGA, Nd3+ ions do not pass into the SC phase. The extraction efficiency increases with decreasing temperature and with increasing nitric acid concentration CNA in the aqueous solution. At 313 K, CNA > 1.5 mol/L, TODGA content not less than 100 mol/g-at. Nd, and CO2pressure ensuring complete dissolution of TODGA (19.0 MPa), Nd3+ completely pass into the SC phase. With increasing content of neodymium ions in the system, the pressure and amount of CO2 required for complete dissolution of TODGA increase. This is likely to be due to a decrease in the intensity of intermolecular interactions in the SC phase during the passage of polar Nd complexes with TODGA and nitrate ions into it. [ABSTRACT FROM AUTHOR]

The overall purpose of this study is to investigate the potential for producing higher energy biogas at elevated fermentation pressures. Upgrading of biogas is often carried out to increase its methane (energy) content by removing carbon dioxide. Upgrading is used, for example, to give methane of sufficient purity that it can be injected directly into the gas supply grid. In this research, freshwater algae are used as the feedstock for anaerobic digestion (AD) to produce biogas as a source of renewable energy. Although this has been the subject of extensive research over the past few decades, the main reason why AD has not been more widely commercialised is because it can have poor economic viability. In this paper, we used two similar bioreactors of capacity 1.5 L to generate biogas at different pressures. The methane concentration of the biogas increases to at least 70.0% for a headspace pressure greater than 4 bara compared to 57.5% or less when the pressure is less than 1.6 bara. The higher pressure operation therefore reduces the amount of upgrading required leading to a reduction in the cost of this step. Another interesting finding of this study is that the solubility of biogas in the digestate is estimated to be only 3.7% (best fit value) of its solubility in pure water, which is much lower than the values previously reported in the literature. [ABSTRACT FROM AUTHOR]

Purpose: Wildfire is one of the most important natural disturbances in forest and multi-vegetation ecosystems, directly or indirectly affecting the structural processes and functions of forest ecosystems with varying degrees. Wildfire releases vast amounts of carbon dioxide and other substances by destroying vegetation, making itself an important topic for the study of global change and environmental impacts. Therefore, a deeper understanding of this topic is particularly crucial for managing forest ecosystems. Methods: This paper was based on a literature search of the Web of Science database for international forest wildfire research, utilizing bibliometric and quantity statistical analysis methods. Results: The results show that forest wildfire research has been rapidly growing over the last 20 years, with the number of relevant articles generally increasing yearly at an average annual growth rate of about 22.45%. The US tops the list in terms of total and independent publications, with a total of 3111 articles (49.88%). The key journals publishing on this topic include 12 journals, Stephens S.L., Bergeron Y., and Lindenmayer D.B. are the key contributing authors to the field, and research institutions are primarily concentrated in the US Forest Service. Keyword co-occurrence analysis shows that current forest wildfire research is focused on seven main areas. This paper systematically reviewed the progress and hotspots of international forest wildfire research in recent decades, mainly focusing on occurrences, severity, management, and warning techniques for wildfires, as well as the impact of climate change and human activities on wildfires. Conclusions: The study concludes that research trends in this field have undergone a significant evolution in recent decades. The future forest wildfire research moves towards a combination of typical mechanisms and large-scale effects across spatial and temporal scales, deep integration of aerospace and earth observations and precise simulations, discipline fusion, and couplings research. We believe that this study provides a comprehensive and systematic overview for future forest wildfire observation, prediction, management, and investigation of ecological effects. [ABSTRACT FROM AUTHOR]

In this study, we conduct a comprehensive history matching study for the FluidFlower benchmark model. This benchmark was prepared and organized by the University of Bergen, the University of Stuttgart, and Massachusetts Institute of Technology, for promoting understanding of the complex physics of geological carbon storage (GCS) through in-house experiments and numerical simulations. This paper synthesizes the experiences of history matching the benchmark data encountered by the Delft-DARTS and CSIRO participants. History matching is first performed based on a low-dimensional-zonated structured model using a simple Poisson-like solver. The permeability of six facies and two faults is inferred in this stage to match the digitized concentration data. The history matching is then further enhanced to richer spatial and physical models to capture the spatial variation of permeability and buoyancy effects, using an unstructured grid. Efficient adjoint methods are used to evaluate the gradient used in the optimization of data misfits or equivalent Bayesian log-likelihoods. With efficient optimization methods available for both maximum a posteriori model inference and Randomized Maximum Likelihood methods for model uncertainty, we perform history matching using both binary and continuous concentration observations. The results show that the tracer plumes in the enriched model match the experimental plumes more accurately compared with the results from the parsimonious-zonated model. The history matching results based on the concentration observations provide more similar plume shapes compared with the case based on the binary observations. The permeability difference between the model before and after history matching reveals that the tracer plume zone and the high permeable zone are the regions of high sensitivity in terms of data misfit between the model response and observations. Surprisingly, CO 2 concentration plume forecasts based on these history-matched models were not especially sensitive to the improvements observed in the enhanced model. [ABSTRACT FROM AUTHOR]

Successful deployment of geological carbon storage (GCS) requires an extensive use of reservoir simulators for screening, ranking and optimization of storage sites. However, the time scales of GCS are such that no sufficient long-term data is available yet to validate the simulators against. As a consequence, there is currently no solid basis for assessing the quality with which the dynamics of large-scale GCS operations can be forecasted. To meet this knowledge gap, we have conducted a major GCS validation benchmark study. To achieve reasonable time scales, a laboratory-size geological storage formation was constructed (the "FluidFlower"), forming the basis for both the experimental and computational work. A validation experiment consisting of repeated GCS operations was conducted in the FluidFlower, providing what we define as the true physical dynamics for this system. Nine different research groups from around the world provided forecasts, both individually and collaboratively, based on a detailed physical and petrophysical characterization of the FluidFlower sands. The major contribution of this paper is a report and discussion of the results of the validation benchmark study, complemented by a description of the benchmarking process and the participating computational models. The forecasts from the participating groups are compared to each other and to the experimental data by means of various indicative qualitative and quantitative measures. By this, we provide a detailed assessment of the capabilities of reservoir simulators and their users to capture both the injection and post-injection dynamics of the GCS operations. [ABSTRACT FROM AUTHOR]

The CO2 enhanced oil recovery(EOR) technology is widely utilized in the development of shale oil reservoirs. However, reservoir plugging issues often occur during the CO2 injection process, leading to reduced onsite development efficiency. Currently, the mechanism behind reservoir plugging is still unclear. Therefore, this research selects Jimsar crude oil from Xinjiang to conduct CO2 displacement experiments on shale cores and analysis of crude oil components. A comparative analysis is conducted with previous studies to explore the plugging mechanism. The research results demonstrate that core plugging occurs when the displacement pressure exceeds 25 MPa, resulting in a significant decrease in core permeability. Under a displacement pressure of 40 MPa, the additional resistance accounts for as much as 72% of the total resistance, with high asphalt content and the extractive effect of CO2 on crude oil components being important factors leading to core plugging. Therefore, in the field development process, the CO2 enhanced oil recovery technology should be applied in a rational and tailored manner according to the properties of the field's crude oil. [ABSTRACT FROM AUTHOR]

Agriculture is the leading sector that is responsible for global climate change through its significant contribution to greenhouse gas (GHG) emissions. Intriguingly, sub-Saharan Africa (SSA) is experiencing higher temperatures and lesser rainfall due to climate change enhanced by anthropogenic GHG emissions. Agriculture and energy use in the SSA predominantly influence the anthropogenic GHG leading to global warming. Therefore, reducing agricultural GHG emissions (such as carbon dioxide, nitrous oxide, and methane) plays a significant role in climate change adaptation. This paper reviews the potential implication of agriculture and energy use on climate change and its implications on environmental sustainability in SSA. Herewith, we explored various GHGs emitted through agriculture-energy use, their effects on climate change, as well as several climate change adaptation mechanisms, and gaps in existing knowledge that necessitate more research, were also explored. We found that agriculture had negative implications on climate change impacts in the SSA countries and that a more focused strategy that is both economically and technically feasible in terms of preferences for land use, effective energy use, and food supply would aid in GHG emission reduction and environmental sustainability. Adapting to the projected changes in the short term while investing in long-term mitigation strategies might be the only way toward a sustainable environment in this region. [ABSTRACT FROM AUTHOR]

A colorimetric assay was developed which has the capability of determining urea in biological samples. It is an origami paper-based sensor consisting of silver nanoparticles that were synthesized by using two different capping agents: thiomalic acid and maltol. The function of the assay relied on hydrolysis of urea to ammonia and carbon dioxide in the presence of urease. The products interacted with nanoparticles which caused aggregation. Interestingly, thiomalic acid capped with silver nanoparticles were selective to ammonia, and the other nanoparticles synthesized by maltol responded to carbon dioxide. These interactions turned the color of nanoparticles from yellow to brown and red, respectively. The resulting colorations were captured by a floatable scanner. A routine image analysis software was utilized to provide the response of the assays. The method was applied to individually determine ammonia, carbon dioxide, and urea. The linear range was 0.06 mg.dL−1-170.0 mg.dL−1 for ammonia, 0.08 mg.dL−1-220.0 mg.dL−1 for carbon dioxide, and 0.5 mg.dL−1-200.0 mg.dL−1 for urea. The respective limits of detection were 0.03 mg.dL−1, 0.06 mg.dL−1, and 0.18 mg.dL−1. No interferences were found in the detremination of urea. The method demonstrates a reliable performance for determination of urea in both saliva and blood samples. [ABSTRACT FROM AUTHOR]

It has been a crucial challenge for countries worldwide to reduce carbon dioxide (CO2) emissions. China is developing policies among various industries to peak CO2 emissions as soon as possible and expects the reduction of CO2 emissions through financial development. This paper explores the influencing mechanism of financial development on CO2 emissions based on panel data from provinces in China, considering constraints of technological innovation and fossil energy dependence among provinces and periods. Empirical results consistently indicate that the effect of China's financial development on CO2 emissions per capita is significantly negative, and it also presents an inverted U-shaped pattern. In those provinces or periods witnessing lower technological innovation and higher fossil energy dependence, the financial development has more significant effect on carbon emission reduction. This result suggests that regions with deficiencies in the development of technology industries, lower proportions of the tertiary industry, and a higher percentage of the secondary industry need to focus more on the value of financial development. [ABSTRACT FROM AUTHOR]

Trying to understand how the interdependence relationship among the sectors of a given economy and its impacts on the environment is fundamental to the identification of sectors that are more polluting and those that are considered key in the sense of being less polluting. In order to describe this relationship, this work has as general objective to measure the level of CO2 emission from the level of production in function of the consumption of electric energy in the state of Mato Grosso do Sul. In order to meet the general objective, from the state energy balance and the input–output matrix of 2010, a hybrid input–output matrix was derived. Thus, it was possible to identify that the service sector, although is the engine of the state GDP, represents only 16% of the emissions, agriculture and cattle raising 6% and industry 78%. The main sectors in CO2 emission are rubber and plastic articles and the pulp and paper production sector. Considering the estimates of growth of the state, the concern with the environment is emphasized as the driving sectors of the expansion being precisely those that emit more CO2. [ABSTRACT FROM AUTHOR]

Despite the efforts to transition to a low carbon economy, greenhouse gas emissions are surging to critical levels. Carbon dioxide removals (CDR) methods, such as direct air capture (DAC), have been gaining substantial public attention in the last few years. DAC is essential in curbing CO2 concentrations and achieving climate targets. It is said that DAC can be deployed at anywhere, but a throughout life cycle assessment (LCA) is imperative to prove its viability. Therefore, this paper aims to explore the feasibility of constructing a 1 MT CO 2 plant in Ireland, using Kinsale and Corrib gas fields as storage points. The results showed that the country is an ideal candidate for scaling up this emerging industry. The efficiency is primarily influenced by the construction of the pipeline section, given a reliable sources of heat and electricity. The study highlights the significant impact of distances to the storage points on feasibility, favouring counties near of the gas fields. In conclusion, Ireland has the potential to establish its own DAC industry. [ABSTRACT FROM AUTHOR]

In this paper, we study the protective effectiveness of the inhibitory composition (25–200 mg/L) against carbon steel corrosion in model formation waters NACE and M1 containing 400 mg/L of H2S individually and together with CO2 using gravimetry, potentiodynamic polarization, and impedance spectroscopy. Its ability to affect the diffusion of hydrogen into the metal and the development of sulfate-reducing bacteria is also estimated. Under static conditions, the protective effect is 73% in the NACE environment and 62% in the M1 environment at room temperature and 74 and 83% at 80°C, respectively. Under hydrodynamic conditions, the protective effect of the composition in the presence of a hydrocarbon phase (10%) reaches 90% in the NACE environment and 77% in the M1 environment. The inhibitory composition accelerates the diffusion of hydrogen into the metal and suppresses the growth of sulfate-reducing bacteria in the Postgate nutrient medium. [ABSTRACT FROM AUTHOR]

Collaborative disposal of sludge has been applied extensively in cement industry kilns, but the influence of organic components in sludge on the selective non-catalytic reduction (SNCR) denitrification is still in highly demanding. This paper focuses the influence of ethanol, n-octane, benzene, and acetone on the SNCR denitrification, and the influence of ethanol are analyzed on SNCR denitrification under different flue gas condition. The result showed that the presence of organic components reduces the reaction temperature of SNCR. When the temperature of SNCR reaction is at 750 ~ 800 ℃, the denitrification rate of four organic components is ethanol > benzene > n-octane > acetone. The optimum denitrification rate on SNCR can reach as high as 90.377% when the reaction condition is the NH3/NO is 1; the ethanol concentration is 1000 ppm; O2 concentration is 2%; and temperature is 750 ℃. The presence of carbon dioxide inhibits the denitrification reaction. With the increase of temperature, the influence of SO2 on the denitrification reaction first increases and then decreases. In this paper, the influence of organic components in sludge on SNCR denitrification will be analyzed, which provides a theoretical basis for the selection of sludge dosing method for cement kiln collaborative disposal. [ABSTRACT FROM AUTHOR]

Despite the efforts to transition to a low carbon economy, greenhouse gas emissions are surging to critical levels. Carbon dioxide removals (CDR) methods, such as direct air capture (DAC), have been gaining substantial public attention in the last few years. DAC is essential in curbing CO2 concentrations and achieving climate targets. It is said that DAC can be deployed at anywhere, but a throughout life cycle assessment (LCA) is imperative to prove its viability. Therefore, this paper aims to explore the feasibility of constructing a 1 MT CO 2 plant in Ireland, using Kinsale and Corrib gas fields as storage points. The results showed that the country is an ideal candidate for scaling up this emerging industry. The efficiency is primarily influenced by the construction of the pipeline section, given a reliable sources of heat and electricity. The study highlights the significant impact of distances to the storage points on feasibility, favouring counties near of the gas fields. In conclusion, Ireland has the potential to establish its own DAC industry. [ABSTRACT FROM AUTHOR]

The development and renewal of gas sensor technology have enabled more and more low-cost gas sensors to form a carbon monitoring network to meet the requirements of the city. In the context of China's commitment to achieving the "double carbon" target by 2060, this paper reviews the principles of four standard gas sensors and the application of several low-cost sensors in urban carbon monitoring networks, with the aim of providing a practical reference for the future deployment of carbon monitoring networks in Chinese cities. Moreover, the types, prices, and deployment of the sensors used in each project are summarized. Based on this review, non-dispersive infrared sensors have the best performance among the sensors and are commonly used in many cities. Lots of urban climate networks in cities were summarized by many reviews in the literature, but only a few sensors were studied, and they did not consider carbon dioxide (CO2) sensors. This review focuses on the dense CO2 urban monitoring network, and some case studies are also discussed, such as Seoul and San Francisco. To address the issue of how to better ensure the balance between cost and accuracy in the deployment of sensor networks, this paper proposes a method of simultaneously deploying medium-precision and high-precision fixed sensors and mobile sensors to form an urban carbon monitoring network. Finally, the prospects and recommendations, such as different ways to mitigate CO2 and develop an entire carbon monitoring system for future urban carbon monitoring in China, are also presented. [ABSTRACT FROM AUTHOR]

Carbon Integration methods help identify the appropriate allocation of captured carbon dioxide (CO2) streams into CO2-using sinks, and are especially useful when a number of CO2 sink options are present simultaneously. The method helps identify CO2 allocation scenarios when subjected to an emission target on the CO2 overall network. Many carbon dioxide sink options are costly, and more often than not, require a high purity carbon dioxide source to satisfy the sink demand. Hence, it is imperative to effectively incorporate treatment units in such networks, to obtain high-purity CO2 streams. In fact, it has been previously reported in many studies that the most expensive step in Carbon Capture, Utilization and Sequestration (CCUS) is the treatment system. As a result, this paper focuses on reassessing the performance of carbon integration networks using a more rigorous cost model for the treatment design stage. The effect of utilizing different treatment operating conditions on the overall cost of the treatment stage of CO2 (before allocation) is first captured using a detailed cost model. Subsequently, this information is then fed into a network design problem that involves a CO2 source-sink allocation network problem, and different CO2 net capture targets within the network. For this, an enhanced treatment model that captures all necessary treatment design parameters has been utilized alongside the original model. The original carbon integration formulation has been adopted from previous work. Many of the cost items have been lumped into single parameters in the original formulation, and lack the necessary depth required to carry out the necessary investigations for this work. Hence, the treatment model introduced in this paper is more rigorous, as it accounts for important technical performance constraints on the system to be assessed. Utilizing a more detailed cost model was found to be very helpful in understanding several effects of varying parameters on the overall source-sink allocations, when subjected to different CO2 net emission reduction targets. The cost of the carbon network increases when the solvent temperatures are increased. However, there was a noticeable linear trend at lower temperatures compared to higher temperatures, where the increase became non-linear. Furthermore, it was discovered that for net capture targets of 20% and 25%, no revenue from carbon storage could be generated beyond a solvent temperature of 25 °C. Additionally, the optimal diameter of the treatment column was more responsive to changes in solvent temperature for cases with low net capture targets (below 10%), while its sensitivity decreased for higher capture targets (above 10%). [ABSTRACT FROM AUTHOR]

Reducing emissions of harmful substances in the production of electricity at thermal power plants is an intensive task, which can be solved by switching to semiclosed cycles with oxygen combination of fuel and carbon dioxide working fluid. The main advantage of the promising technology, which is the absence of the danger of the formation of toxic substances and the ease of separation of excess carbon dioxide, is provided by burning hydrocarbons in high purity oxygen. This paper presents the results of developing the new power equipment preliminary design: an oxy-fuel combustion chamber, a cooled carbon dioxide turbine, and a high-temperature regenerator. The results of mathematical simulation of physical processes that occurred in the main power equipment are presented. Special attention is paid to calculations of methane--oxygen mixture combustion kinetics in excess carbon dioxide medium and numerical analysis of the processes in the oxy-fuel combustion chamber with taking into account the need to cool the flame tube. The optimal mass ratio of carbon dioxide in the mixture of solvent with oxygen equal to 0.872 is determined, at which the minimal incomplete combustion of fuel can be achieved. The temperature state of the carbon dioxide turbine first-stage nozzle vane was mathematically simulated. The simulation results confirmed the possibility to ensure a sufficient uniformity degree of the temperature field due to making a number of small-radius cooled channels near the airfoil outer surface. A few configurations of heat transfer surfaces for the plate regenerator of the oxy-fuel power unit are proposed. Flow turbulizers with a cylindrical shape and with a fin-type airfoil, and also both of their design versions with ribs were used. The obtained mathematical simulation results have shown that of all channels considered, at the Reynolds number values up to 78 000, the ones having turbulizers with ribs show the best thermal-hydraulic efficiency, whereas at higher Re number values, channels having turbulizers without ribs show the best performance. [ABSTRACT FROM AUTHOR]

Carbon dioxide (CO2) emissions from aquatic ecosystems are an important component of the karst carbon cycle process and also a key indicator for assessing the effect of karst carbon sinks. This paper reviewed the CO2 partial pressure (pCO2) and its diffusion flux (FCO2) in karst surface aquatic ecosystems, mainly rivers, lakes, and reservoirs, and their influencing factors summarized the methods for monitoring CO2 emissions in karst aquatic ecosystems and discussed their adaptation conditions in karst areas. The pCO2 and FCO2 decreased in the order of rivers > reservoirs > lakes, and the values in karst lakes were eventually significantly lower than those in global lakes. The pCO2 and FCO2 of karst aquatic ecosystems had patterns of variation with diurnal, seasonal, water depth and hydrological cycles, and spatial and temporal heterogeneity. The sources of CO2 in karst waters are influenced by both internal and external sources, and the key spatial and temporal factors affecting the CO2 emissions from karst rivers, lakes, and reservoirs were determined in terms of physicochemical indicators, biological factors, and biogenic elements; additionally, the process of human activity interference on CO2 emissions was discussed. Finally, a conceptual model illustrating the impacts of urban development, agriculture, mining, and dam construction on the CO2 emissions at the karst surface aquatic ecosystem is presented. Meanwhile, based on the disadvantages existing in current research, we proposed several important research fields related to CO2 emissions from karst surface aquatic ecosystems. [ABSTRACT FROM AUTHOR]

Porous polymer beads with grafted poly(tertiary amine) were prepared by grafting triethylenetetramine to porous crosslinked poly(methyl acrylate) beads via ester amidation reaction, followed by Eschweiler–Clarke methylation reaction using formaldehyde and formic acid to converting the primary and secondary amine groups to tertiary amines in the beads. The tertiary amine groups in the beads were protonated with hydrochloric acid, hydrobromic acid or hydriodic acid, and the protonated tertiary amine group-containing beads showed high catalytic activity and high selectivity for the formation of propylene carbonate through cycloaddition of propylene oxide with CO2, while free tertiary amine group-containing beads exhibited almost no catalytic activity. The recyclability of the catalyst was studied, and slight loss of the activity was observed after five runs. [ABSTRACT FROM AUTHOR]

The exchange of trace gases between the atmosphere and the ocean plays a key role in the Earth's climate. Fluxes at the air-sea interface are affected mainly by wind blowing over the ocean and seawater temperature and salinity changes. This study aimed to quantify the use of CO 2 partial pressure (pCO 2 ) measurements at different depths (1, 5, and 10 m) in ocean surface layers to determine CO 2 fluxes (FCO 2 ) and to investigate the impacts of wind-sheltered and wind-exposed regions on the carbon budget. Vertical profiles of temperature, salinity, and pCO 2 were considered during a daily cycle. pCO 2 profiles exhibited relatively high values during sunny hours, associated with relatively high sea temperatures. However, the largest FCO 2 corresponded with higher wind speeds. Estimated fluxes between measurements at 1 and 10 m depths decreased by 71% in the sheltered region and 44% in the exposed region. According to the SOCAT dataset, at a depth of 5 m, the Atlantic basin emits approximately 0.29 Tg month - 1 of CO 2 to the atmosphere; nevertheless, our estimates suggest that FCO 2 at the surface is 12.02 Tg month - 1 , which is 97.6% greater than that at 5 m depth. Therefore, future studies should consider sampling depth to adequately estimate the FCO 2 . [ABSTRACT FROM AUTHOR]

In the context of ever-growing demand for food and associated concerns regarding the environmental impacts of high-input agricultural systems, there is growing interest in mixed farm enterprises to deliver greater sustainability compared with mono-enterprise production systems. However, assessments of such systems are complex and require high-resolution data to determine the true value and interconnectivity across enterprises. Given the scarcity of information on mixed crop–livestock systems and the difficulties of its analysis, we perform life cycle assessment using temporally high-resolution data (2019–2022) from a long-term experiment in South America to evaluate the 'cradle-to-farmgate exit' greenhouse gas emissions intensities of four rotational crop–livestock systems. Systems evaluated were continuous cropping: 2 years of continuous cropping; short rotation: 2-year continuous cropping plus 2-year pasture; long rotation: 2-year continuous cropping followed by 4-year pasture; and forage rotation: continuous pasture. Emissions intensities for beef throughput were reported as kilograms of carbon dioxide equivalents (CO2-eq) per kilogram of liveweight gain (LWG) using the Intergovernmental Panel for Climate Change's Sixth Assessment Report (AR6 2021) CO2 characterisation factors. Point estimate results were found to be 11.3, 11.8, 11.8 and 16.4 kg CO2-eq/kg/LWG for continuous cropping, short rotation, long rotation and forage rotation, respectively. Emission averages arising from crops, which were separated from animal-based emissions using economic allocation, were 1.23, 0.53 and 0.52 kg CO2-eq/kg for soybean, wheat and oat, respectively. The inclusion of soil organic carbon stock changes had notable effects on reducing each system's emissions: by 22.4%, 19.2%, 25.3% and 42.1% under continuous cropping, short rotation, long rotation and forage rotation, respectively, when soil organic carbon was included. Given there are few life cycle assessment studies available on such mixed-enterprise 'semi-circular' systems, particularly with novel primary data, this study adds critical knowledge to agri-food-related sustainability literature by addressing environmental issues in complex production systems compared to extant and broad coverage of mono-enterprise systems. [ABSTRACT FROM AUTHOR]

A sample of a catalytic system based on nickel and a carbon-containing material, microcellulose, was obtained using a hydrothermal synthesis method. A catalytic study of the synthesized system in the process of selective hydrogenation of carbon monoxide and carbon dioxide was carried out with calculation of the apparent activation energy. The sample was demonstrated to be highly active in the selective hydrogenation reactions of carbon oxides. A 100% conversion of carbon monoxide and carbon dioxide and selectivity for methane of 90 and 80%, respectively, were obtained. [ABSTRACT FROM AUTHOR]

Methanogenic hydrocarbon degradation can be carried out by archaea that couple alkane oxidation directly to methanogenesis, or by syntrophic associations of bacteria with methanogenic archaea. However, metagenomic analyses of methanogenic environments have revealed other archaea with potential for alkane degradation but apparent inability to form methane, suggesting the existence of other modes of syntrophic hydrocarbon degradation. Here, we provide experimental evidence supporting the existence of a third mode of methanogenic degradation of hydrocarbons, mediated by syntrophic cooperation between archaeal partners. We collected sediment samples from a hot spring sediment in Tengchong, China, and enriched Hadarchaeota under methanogenic conditions at 60 °C, using hexadecane as substrate. We named the enriched archaeon Candidatus Melinoarchaeum fermentans DL9YTT1. We used 13C-substrate incubations, metagenomic, metatranscriptomic and metabolomic analyses to show that Ca. Melinoarchaeum uses alkyl-coenzyme M reductases (ACRs) to activate hexadecane via alkyl-CoM formation. Ca. Melinoarchaeum likely degrades alkanes to carbon dioxide, hydrogen and acetate, which can be used as substrates by hydrogenotrophic and acetoclastic methanogens such as Methanothermobacter and Methanothrix. Methanogenic hydrocarbon degradation can be carried out by archaea either by coupling alkane oxidation directly to methanogenesis, or in syntrophic associations with bacteria. Here, the authors provide experimental evidence supporting that methanogenic degradation of hydrocarbons can also be mediated by syntrophic cooperation between archaeal partners. [ABSTRACT FROM AUTHOR]

Although several studies examine the convergence of per capita carbon dioxide (CO2) at the country level, research at the regional level is scarce except in countries like China and the USA. This study bridges this research gap by considering India's regional-level CO2 emissions convergence. In particular, this study proposes to undercover the convergence patterns of carbon emissions towards designing effective carbon reduction policies in the future at the regional level in India. Addressing this research is vital since this question is closely allied with fairness in the distribution of per capita emissions. In order to achieve the stated objective, this study first computes per capita CO2 emissions. Then, it uses the convergence notion to analyse the CO2 emissions in the case of 16 Indian states from 2003–04 to 2018–19. By employing Phillips and Sul's clustering procedure, this study supports the presence of overall divergence when all 16 Indian states are considered as a group. This suggests that all states together are not forming a single steady state rather, they are forming multiple steady (or club convergence) due to heterogeneity in per capita CO2 emissions. Moreover, 16 states cluster into three clubs which have distinct transition paths. From the policy perspective, it is important for the government of India to target reducing per capita CO2 emissions by focusing on clusters of states in a phase-wise manner. [ABSTRACT FROM AUTHOR]

Effective management of surface emissions from abandoned gob methane (AGM) is crucial for mitigating greenhouse gas emissions and ensuring public safety. An important geochemical characteristic of near-surface AGM migration is the potential presence of abnormal component concentrations in near-surface soil gas over abandoned coal gobs. To investigate this phenomenon, a surface geochemical survey was conducted based on four survey lines in the Dongyi and Dongsan abandoned gob groups in the Xinghua Coal Mine, Jixi Basin, in China. The gas chromatography technique was used to analyze the concentrations of methane, carbon dioxide, ethane, propane, and butane in the collected 43 soil gas samples. The results revealed a significant anomaly of soil gas concentrations, particularly methane and carbon dioxide anomalies, in the near-surface soil over abandoned gobs. The background concentration for methane was determined to be 7.49 ppm, with an anomalous threshold set at 10 ppm based on a statistical analysis and an iterative method. This threshold could be confirmed by examining the coupling and decoupling relationship between methane, carbon dioxide, and C2–3 as well. A spatial correlation between regions exhibiting anomalous methane and carbon dioxide concentrations and the positions of gob areas, abandoned surface wells, and faults was observed. Abandoned and sealed coalbed methane surface wells and faults near gas-rich gob areas have the potential to act as conduits for AGM leakage to the surface. Furthermore, concentrations of methane, carbon dioxide, and C2–3 in soil gas over abandoned coal gobs were significantly higher compared to areas unaffected by mining activities. This suggests that elevated concentrations of methane, carbon dioxide, and C2–3 in soil gas may originate from underground AGM. [ABSTRACT FROM AUTHOR]

The direct co-conversion of methane and carbon dioxide into valuable chemicals has been a longstanding scientific pursuit for carbon neutrality and combating climate change. Herein, we present a photo-driven chemical process that reforms these two major greenhouse gases together to generate green methanol and CO, two high-valued industrial chemicals. Isotopic labeling and control experiments indicate an oxygen-atom-graft occurs, wherein CO2 transfers one O into the C–H bond of CH4 via photo-activated interfacial catalysis with AuPd nanoparticles supported on GaN. The photoexcited AuPd/GaN interface effectively orchestrates the CH4 oxidation and the CO2 reduction producing 13.66 mmol g−1 of CH3OH yield over 10 h. This design provides a solid scientific basis for the photo-driven oxygen-atom-grafting process to be further extended to visible light region. The direct co-conversion of CH4 and CO2 into valuable chemicals has been a longstanding scientific pursuit. Here, the authors present a photo-driven process that reforms these greenhouse gases together to generate CH3OH and CO over AuPd/GaN. [ABSTRACT FROM AUTHOR]

Existing studies indicate that future global carbon dioxide (CO2) removal (CDR) efforts could largely be concentrated in Asia. However, there is limited understanding of how individual Asian countries and regions will respond to varying and uncertain scales of future CDR concerning their energy-land-water system. We address this gap by modeling various levels of CDR-reliant pathways under climate change ambitions in Asia. We find that high CDR reliance leads to residual fossil fuel and industry emissions of about 8 Gigatonnes CO2yr−1 (GtCO2yr−1) by 2050, compared to less than 1 GtCO2yr−1 under moderate-to-low CDR reliance. Moreover, expectations of multi-gigatonne CDR could delay the achievement of domestic net zero CO2 emissions for several Asian countries and regions, and lead to higher land allocation and fertilizer demand for bioenergy crop cultivation. Here, we show that Asian countries and regions should prioritize emission reduction strategies while capitalizing on the advantages of carbon removal when it is most viable. Global future carbon removal efforts could largely be concentrated in Asia. Here, this study shows that multi-gigatonnes expectation of carbon removal could have adverse impact on the energy-land-water system of countries and regions within the continent. [ABSTRACT FROM AUTHOR]

Photoionization can initiate structural reorganization of molecular matter and drive formation of new chemical bonds. Here, we used time-resolved extreme ultraviolet (EUV) pump – EUV probe Coulomb explosion imaging of carbon dioxide dimer ion C O 2 2 + dynamics, that combined with ab initio molecular dynamics simulations, revealed unexpected asymmetric structural rearrangement. We show that ionization by the pump pulse induces rearrangement from the slipped-parallel (C2h) geometry of the neutral C O 2 dimer towards a T-shaped (C2v) structure on the ~100 fs timescale, although the most stable slipped-parallel (C2h) structure of the ionic dimer. Moreover, we find that excited states of the ionized C O 2 dimer can exhibit formation of a CO 3 moiety in the C 2 O 4 + complex that can persist even after a suitably time-delayed second photoionization in a metastable C 2 O 4 2 + dication. Our results suggest that charge asymmetry plays an important role in the ionization-induced dynamics in such dimers that are present in C O 2 rich environments. In a time-resolved Coulomb explosion imaging study using ultrafast extreme ultraviolet pulses, combined with theoretical simulations, authors reveal unexpected asymmetric rearrangement of carbon dioxide dimer ion, including a CO3 moiety formation. [ABSTRACT FROM AUTHOR]