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This paper reviews the properties of methanesulfonic acid (MSA) and its potential for use in hydrometallurgy. Although MSA is much less known than sulfuric, hydrochloric or nitric acid, it has several appealing properties that makes it very attractive for the development of new circular flowsheets in hydrometallurgy. Unlike other organic acids such as acetic acid, MSA is a very strong acid (pKa = − 1.9). In addition, it is very stable against chemical oxidation and reduction, and has no tendency to hydrolyze in water. In terms of its environmental impact, MSA has low toxicity and is biodegradable. In nature, it is part of the geochemical sulfur cycle. A useful property is the high solubility of its salts in water: methanesulfonate salts have a much higher solubility in water than sulfate salts. Additionally, MSA and its salts are compatible with the electrowinning of metals because the anode reaction involves the formation of oxygen gas (unlike chlorine gas formation in chloride electrolytes) and no cathodic reduction of the anion occurs (unlike nitrate reduction in nitrate electrolytes). MSA is particularly interesting for lead hydrometallurgy, where it offers more environment-friendly alternatives to HBF4 and H2SiF6. However, MSA can also be adopted in all hydrometallurgical processes that require strong Brønsted acids. It can be used in the metallurgy of copper, zinc, cobalt, nickel, and rare earths, as well as in the recycling of metals from end-of-life products. Although MSA itself is a non-oxidizing acid, in combination with hydrogen peroxide it yields strongly oxidizing lixiviants that can leach copper from chalcopyrite or dissolve metallic silver. The global production of MSA is expected to increase rapidly in the near future thanks to both the industrialization of a new sustainable synthesis process and its many applications (cleaning fluids, electrolytes for electroplating, redox-flow batteries, catalysts in organic synthesis, and as a solvent for high-molecular-weight polymers). As a result, MSA will become more widely available and a lower price will make it an increasingly attractive option. Graphical Abstract

In this academic position paper, we propose the 12 Principles of a novel and more sustainable approach to hydrometallurgy that we call “circular hydrometallurgy.” The paper intends to set a basis for identifying future areas of research in the field of hydrometallurgy, while providing a “sustainability” benchmark for assessing existing processes and technological developments. Circular hydrometallurgy refers to the designing of energy-efficient and resource-efficient flowsheets or unit processes that consume the minimum quantities of reagents and result in minimum waste. The application of a circular approach involves new ways of thinking about how hydrometallurgy is applied for both primary and secondary resources. In either case, the emphasis must be on the regeneration and reuse of every reagent in the process. This refers not only to the acids and bases employed for leaching or pH control, but also any reducing agents, oxidizing agents, and other auxiliary reagents. Likewise, the consumption of water and energy must be reduced to an absolute minimum. To consolidate the concept of circular hydrometallurgical flowsheets, we present the 12 Principles that will boost sustainability: (1) regenerate reagents, (2) close water loops, (3) prevent waste, (4) maximize mass, energy, space, and time efficiency, (5) integrate materials and energy flows, (6) safely dispose of potentially harmful elements, (7) decrease activation energy, (8) electrify processes wherever possible, (9) use benign chemicals, (10) reduce chemical diversity, (11) implement real-time analysis and digital process control, and (12) combine circular hydrometallurgy with zero-waste mining. Although we realize that the choice of these principles is somewhat arbitrary and that other principles could be imagined or some principles could be merged, we are nevertheless convinced that the present framework of these 12 Principles, as put forward in this position paper, provides a powerful tool to show the direction of future research and innovation in hydrometallurgy, both in industry and in academia. Graphical Abstract

UNLABELLED: A hydrometallurgical process is described for conversion of an aqueous solution of lithium chloride into an aqueous solution of lithium hydroxide via a chloride/hydroxide anion exchange reaction by solvent extraction. The organic phase comprises a quaternary ammonium chloride and a hydrophobic phenol in a diluent. The best results were observed for a mixture of the quaternary ammonium chloride Aliquat 336 and 2,6-di-tert-butylphenol (1:1 molar ratio) in the aliphatic diluent Shellsol D70. The solvent extraction process involves two steps. In the first step, the organic phase is contacted with an aqueous sodium hydroxide solution. The phenol is deprotonated, and a chloride ion is simultaneously transferred to the aqueous phase, leading to in situ formation of a quaternary ammonium phenolate in the organic phase. The organic phase, comprising the quaternary ammonium phenolate, is contacted in the second step with an aqueous lithium chloride solution. This contact converts the phenolate into the corresponding phenol by protonation with water extracted to the organic phase, followed by a transfer of hydroxide ions to the aqueous phase and chloride ions to the organic phase. As a result, the aqueous lithium chloride solution is transformed into a lithium hydroxide solution. The process has been demonstrated in continuous counter-current mode in mixer-settlers. Solid battery-grade lithium hydroxide monohydrate was obtained from the aqueous solution by crystallization or by antisolvent precipitation with isopropanol. The process consumes no chemicals other than sodium hydroxide. No waste is generated, with the exception of an aqueous sodium chloride solution. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s40831-022-00629-2. ispartof: JOURNAL OF SUSTAINABLE METALLURGY vol:9 issue:1 pages:107-122 ispartof: location:Netherlands status: published

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:28 pages:9123-9130 status: published

The past 10–20 years have seen numerous academic papers describing the benefits of ionic liquids (ILs) and deep-eutectic solvents (DESs) for leaching, solvent extraction and electrowinning. The scientific community—including the authors of this opinion article—have frequently proclaimed these neoteric solvents as game-changers in extractive metallurgy. Despite this, there have been no commercial breakthroughs. In this paper we reflect on the reasons why ILs and DESs seem to have failed to impact on the metallurgical industry. These include: (1) issues with high viscosity; (2) limited chemical stability under the conditions of metallurgical processes; (3) difficulties with recycling and reuse; (4) a lack of demonstrated unit processes and flowsheets on the pilot scale; (5) insufficient material-property data available for engineering purposes; (6) the administrative burden of obtaining licenses and safety permits; (7) very high costs for large-scale operations; and (8) minimal added value compared to state-of-the-art hydrometallurgical processes. Our belief is that innovations in hydrometallurgy based on ILs or DESs are unlikely. Instead, we should be aiming for a deeper understanding of hydrometallurgical processes at the molecular level. This is because advances are more likely to derive from the refocused efforts of experienced IL/DES researchers investigating the speciation and chemical thermodynamics of hydrometallurgical solutions, which will then hasten the transition from linear to low-energy-input, circular hydrometallurgy. Graphical Abstract

A Life Cycle Assessment (LCA) was conducted to evaluate the total environmental impact of state-of-the-art Waste-to-Energy (WtE) in Belgium, with respect to recovered energy utilization and addition of Carbon Capture and Storage (CCS). Four energy output scenarios were modelled on Umberto LCA software using primary data of mass and energy flows surrounding the six incinerators at the considered WtE plant, and predefined processes from the Ecoinvent 3.6 database. The normalized LCA results suggest that by utilizing all the recovered energy as steam, the WtE plant can avoid an equivalent annual environmental impact value of approximately 21200, 36800, 6700, 15800, 37000 and 6900 average European citizens in the impact categories ‘climate change’, ‘freshwater and terrestrial acidification’, ‘freshwater eutrophication, ‘photochemical ozone creation’ and ‘respiratory effects, inorganics’, ‘terrestrial eutrophication’, respectively. The ‘Electricity and Steam with CCS’ scenario resulted in the most avoided environmental impact in the impact category ‘climate change’. However, in all other impact categories, it resulted in less avoided environmental impact compared to the ‘Steam’ scenario. The comparative analysis showed that 19 out of 24 of the LCA results varied by more than 50% between two energy substitution models, thus quantifying the influence of energy substitution in LCA modelling. This study exemplifies the environmental benefit WtE technology can realize by substituting conventional energy production processes that are reliant on fossil resources, whilst performing its primary function that is reducing the volume of non-recyclable waste, destroying hazardous organic components it contains and recovering useful materials from it.

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:11 pages:3766-3776 status: published

ispartof: Acs Sustainable Chemistry & Engineering vol:10 issue:9 pages:3048-3056 status: published

ispartof: JOURNAL OF SUSTAINABLE METALLURGY vol:8 issue:1 pages:297-309 status: published

ispartof: JOURNAL OF RENEWABLE MATERIALS vol:11 issue:3 pages:1031-1061 status: published

Using the dihydroxylation of alkenes as a benchmark, the reactivities of fresh and aged solutions of (NH4)2S2O8 (electrochemically generated) were compared to commercially-procured peroxydisulfate and Oxone®. The study revealed that peroxymonosulfate (Caro’s acid, PMS) is the active oxidant in such reactions. Using complementary redox colorimetry and in situ IR spectroscopy to monitor the oxidants, the competitive decomposition of peroxydisulfate in an acidic solution into PMS and H2O2 can be quantified for the first time. The new insight enabled the design and implementation of both batch and flow processes to maximise the concentration of active PMS oxidant. The utility of these oxidants for organic synthesis is demonstrated by the dihydroxylation of eight styrenes and seven alkyl alkenes, where the ammonium PMS solutions performed better than Oxone® (counterion effect). Last but not least, a non-chromatographic method for isolating and purifying the water-soluble diol product was developed.

Electrolytic formic acid synthesis delivers green formic acid at the right concentration for emerging applications.

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:10 issue:1 pages:16-22 status: published

Advantages of ionic liquids (ILs) over volatile organic solvents in chemical processes include no or negligible evaporative losses and high tunability. However, the conventional production of aprotic ILs via metathesis can be unattractive (both economically and environmentally) because of its high complexity, while the performance of other synthesis routes remains unclear. Existing life-cycle assessments furthermore fail to combine the production and use phases of these solvents, leading to erroneous conclusion about their sustainability credentials. This paper compares a one-pot, halide-free production route to 1-butyl-3-methylimidazolium tetrafluoroborate [BMIM][BF4] against metathesis and two conventional fuel desulfurization solvents, namely, acetonitrile and dimethylformamide (DMF). Halide-free synthesis is predicted to reduce the cost and environmental impacts associated with the production of [BMIM][BF4] by 2–5-fold compared to metathesis. Upon including the use phase of the solvents in fuel desulfurization and accounting for the uncertainty in background data, halide-free [BMIM][BF4] consistently presents the lowest cost and environmental impacts, while DMF is the worst in class. As well as exemplifying the importance of synthesis routes of ILs on their sustainability, these results highlight the need to include the use phase of solvents for more comprehensive life-cycle assessments.

The integrated nature of the Sustainable Development Goals (SDGs) presents a challenge to implementing the 2030 Agenda. Analytical methods to support decision-makers are often developed without explicitly incorporating decision-makers’ views and experience. Here, we investigate whether existing methods are fit-for-purpose in supporting decision-makers at national and subnational levels. We identify prominent methods for SDG interaction analysis, which we then evaluate by engaging directly (via a survey and interviews) with method developers and decision-makers in Sweden. We find that decision-makers prioritize methods that are simple and flexible to apply and able to provide directly actionable and understandable results. They are less concerned with the accuracy, precision, completeness or quantitative nature of the knowledge. Prominent categories of methods include self-assessment, expert judgement, literature-based, statistical analyses and modelling. Interviewed decision-makers consider these methods in line with the features prioritized in the survey but highlight low performance on features they value highly, such as the extent to which results are actionable and overall ease of use. Methods developers have limited awareness of decision-makers’ priorities and requirements, so hindering methodological advancement. They should focus on the practical value of applications to support decision-makers, resource-constrained organizations and those seeking to evaluate multiple cases.

Floating offshore wind turbines (FOWTs) have received great attention for deep water wind energy harvesting. So far, research has been focused on a single floating rotor. However, for final deployment of FOWT farms, interactions of multiple FOWTs and potential impacts of the floating motion on power performance and wake of the rotors need to be investigated. In this study, we employ CFD coupled with an Actuator Disc model to analyze interactions of two tandem FOWTs for the scenario, where the upstream rotor is floating with a prescribed surge motion and the downstream rotor is fixed and influenced by the variations in the incoming flow created by the oscillating motion of the surging rotor. We will investigate three different surge amplitudes and analyze the fluctuations in power performance of the two rotors as well as their wake interactions. The results show a light increase in the mean power coefficient of both rotors for the surging case, compared against the case with no surge motion. The standard deviation of the transient CP of the surging rotor linearly scales with the surge amplitude, while such impact for the downstream rotor is very limited. Surging motion of the upstream rotor is found to enhance flow mixing in the wake, which therefore, accelerates the wake recovery of the downstream rotor. This finding suggests prospects for research into redesigning wind farm layout for FOWTs, aiming for more compact arrangements., peer-reviewed

Offshore wind energy has seen a steady increase in the latest years as it serves as an ideal alternative energy source to meet our renewable energy goals. Due to this increase in interest and in installations of offshore wind farms a better understanding of the impact of waves on the power production of wind farms in necessary. This wave-wind farm power production interaction has scarcely been examined, however, some exceptions of small scale large-eddy-simulations exist. Unfortunately, these studies are not able to take multiple wind farms under real weather conditions into account. Here, we show the power production and wake lengths of 1250 offshore wind turbines located in the German Bight simulated by a stand-alone atmospheric (WRF) model and a coupled atmosphere-wave (WRF-SWAN) model. The coupled atmosphere-wave model estimates larger (smaller) power production in case of waves and wind traveling in the same (opposed) direction compared to the stand-alone atmospheric model. The relative difference between the two models can be as much as 20% for the two-week averaged grid power production, while the difference in total power over this two-week period is equal to 9%. Moreover, the wind farm wake lengths of waves and wind traveling in the same (opposed) direction are longer (shorter) for the coupled atmosphere-wave model compared to the stand-alone atmospheric model. Here, the relative difference of the mean wake length between the two models can be up to 25%. This shows the importance of waves as a part of the offshore wind environment and can be an important factor in future wind assessment or power production estimation studies.

Satisfying China’s food demand without harming the environment is one of the greatest sustainability challenges for the coming decades. Here we provide a comprehensive forward-looking assessment of the environmental impacts of China’s growing demand on the country itself and on its trading partners. We find that the increasing food demand, especially for livestock products (~16%–30% across all scenarios), would domestically require ~3–12 Mha of additional pasture between 2020 and 2050, resulting in ~−2% to +16% growth in agricultural greenhouse gas (GHG) emissions. The projected ~15%–24% reliance on agricultural imports in 2050 would result in ~90–175 Mha of agricultural land area and ~88–226 MtCO2-equivalent yr−1of GHG emissions virtually imported to China, which account for ~26%–46% and ~13%–32% of China’s global environmental impacts, respectively. The distribution of the environmental impacts between China and the rest of the world would substantially depend on development of trade openness. Thus, to limit the negative environmental impacts of its growing food consumption, besides domestic policies, China needs to also take responsibility in the development of sustainable international trade.

The environmental impacts of food are currently at unsustainable levels. Consumers undoubtedly play a central role in reducing the impacts of the food system to more sustainable levels via dietary changes and food waste reduction. Mathematical optimisation is one approach to identifying less environmentally impactful dietary patterns. A limited number of studies, however, have assessed whether impact reductions offered by optimised diets are enough to remain within planetary boundaries (i.e. attain ‘absolute’ environmental sustainability). Using UK food consumption as a case study, here we employ linear programming to identify nutritionally adequate diets that meet sociocultural acceptability criteria whilst minimising (a) environmental impact transgressions of their allocated share of the safe operating space (SoSOS) for nine planetary boundaries (PBs), (b) cost, or (c) deviation from the current diet. We show that the current diet is unsustainable as it transgresses six or seven PBs, depending on the SoSOS allocation principle. Optimising for minimum SoSOS transgressions yields diets offering significant impact reductions (66 - 95% reduction across all PBs) compared to the current average dietary pattern, but whether they completely mitigate SoSOS transgressions depends on the sharing principle adopted to assign the SoSOS to national food consumption. Additionally, by comparing least-cost and least-transgression solutions, we find a trade-off between cost and environmental sustainability indicating that more sustainable dietary patterns are not currently incentivised by the relative prices of food items in the UK. Our work demonstrates the value in embedding ‘absolute’ sustainability in diet optimisation so that solutions inherently provide a more clear-cut understanding of their broad implications on the environment., Sustainable Production and Consumption, 28, ISSN:2352-5509

Reductive Catalytic Fractionation (RCF) of lignocellulosic materials produces lignin oil rich in monomer products and high-quality cellulosic pulps. RCF lignin oil also contains lignin oligomers/polymers and hemicellulose-derived carbohydrates. The variety of components makes lignin oil a complex matrix for analytical methods. As a result, the signals are often convoluted and overlapped, making detecting and quantifying key intermediates challenging. Therefore, to investigate the mechanisms underlining lignin stabilization and elucidate the structural features of carbohydrates occurring in the RCF lignin oil, fractionation methods reducing the RCF lignin oil complexity are required. This report examines the solvent fractionation of RCF lignin oil as a facile method for producing lignin oil fractions for advanced characterization. Solvent fractionation uses small volumes of environmentally benign solvents (methanol, acetone, and ethyl acetate) to produce multigram lignin fractions comprising products in different molecular weight ranges. This feature allows the determination of structural heterogeneity across the entire molecular weight distribution of the RCF lignin oil by high-resolution HSQC NMR spectroscopy. This study provides detailed insight into the role of the hydrogenation catalyst (Raney Ni) in stabilizing lignin fragments and defining the structural features of hemicellulose-derived carbohydrates in lignin oil obtained by the H-transfer RCF process. 1

ispartof: ACS SUSTAINABLE CHEMISTRY & ENGINEERING vol:9 issue:34 pages:11596-11603 status: published

The current design of vertical axis wind turbines (VAWTs) suffers from inevitable change in tip speed ratio, λ, in variant wind conditions due to fixed rotor speed. At relatively high wind speeds, which are promising due to high wind power potential, VAWTs operate at low λ with poor power coefficient. Morphing airfoils can be a potential solution by modifying the airfoil shape to optimal at each λ. The optimal airfoil shape for VAWTs at low λ, where dynamic stall is present, has not yet been studied in the literature, therefore, the present study addresses this gap by focusing on this regime to serve as a step towards designing morphing airfoils for VAWTs by identifying the optimal airfoil shape at low λ. The present study performs a combined analysis of three shape defining parameters, namely the airfoil maximum thickness and its position as well as the leading-edge radius, to reveal the overall design space. The analysis is based on 252 high-fidelity transient CFD simulations of 126 identical airfoil shapes. The simulations are verified and validated with three experiments. The results show that the three shape defining parameters have a fully coupled impact on the turbine power and thrust coefficients. When λ reduces from 3.0 to 2.5, the optimal airfoil changes from NACA0018–4.5/2.75 to NACA0024–4.5/3.5, that is increasing the maximum thickness from 18%c to 24%c and shifting its position from 27.5%c to 35%c, while the leading-edge radius index, I, remains 4.5. In general, reducing I from the default value of 6.0 to 4.5 is found to increase the turbine CP.

Wind energy is anticipated to play a central role in enabling a rapid transition from fossil fuels to a system based largely on renewable power. For wind power to fulfill its expected role as the backbone—providing nearly half of the electrical energy—of a renewable-based, carbon-neutral energy system, critical challenges around design, development, and deployment of land and offshore technologies must be addressed. During the past three years, the wind research community has invested significant effort toward understanding the nature and implications of these challenges and identifying associated gaps. The outcomes of these efforts are summarized in a series of ten articles, some under review by Wind Energy Science (WES) and others planned for submission during the coming months. This letter explains the genesis, significance, and impacts of these efforts.

Upcoming biorefineries, such as lignin-first provide renewable aromatics containing unique aliphatic alcohols. In this context, a Cu-ZrO2 catalyzed hydrogen borrowing approach was established to yield tertiary amine from the lignin model monomer 3-(3,4-dimethoxyphenyl)-1-propanol and the actual lignin-derived monomers, (3-(4-hydroxyphenyl)-1-propanol and dihydroconiferyl alcohol), with dimethylamine. Various industrial metal catalysts were evaluated, resulting in nearly quantitative mass balances for most catalysts. Identified intermediates, side and reaction products were placed into a corresponding reaction network, supported by kinetic evolution experiments. Cu-ZrO2 was selected as most suitable catalyst combining high alcohol conversion with respectable aliphatic tertiary amine selectivity. Low pressure H2 was key for high catalyst activity and tertiary amine selectivity, mainly by hindering undesired reactant dimethylamine disproportionation and alcohol amidation. Besides dimethylamine model, diverse secondary amine reactants were tested with moderate to high tertiary amine yields. As most active catalytic site, highly dispersed Cu species in strong contact with ZrO2 is suggested. ToF-SIMS, N2 O chemisorption, TGA and XPS of spent Cu-ZrO2 revealed that imperfect amine product desorption and declining surface Cu lowered the catalytic activity upon catalyst reuse, while thermal reduction readily restored the initial activity and selectivity demonstrating catalyst reuse. ispartof: CHEMSUSCHEM vol:15 issue:19 ispartof: location:Germany status: published

In this paper, we examine the impact of including environmental, social and governance (ESG) criteria in the allocation of equity portfolios. We focus on the risk and return characteristics of the resulting ESG portfolios and investment strategies. Two specific measures are considered to quantify the ESG performance of a company; the ESG rating and the greenhouse gas (GHG) emission intensity. For both measures, we carry out empirical portfolio analyses with assets in either the STOXX Europe 600 or the Russell 1000 index. The ESG rating data analysis does not provide clear-cut evidence for enhanced performance of portfolios with either high or low ESG scores. We moreover illustrate that the choice of rating agency has a significant impact on the performance of the resulting ESG-constrained portfolios. Secondly, we study the impact of GHG emission reductions and increases. We show that emission reductions do not necessarily lead to increased risk or diminished returns, which gives confidence in a smooth transition towards the green economy pursued by the European Green Deal.

Depolymerization of lignin, a key component of lignocellulose, is a sustainable approach to provide value-added aromatics. Selective cleavage of recalcitrant C−C linkages is a key challenge for lignin depolymerization. Photocatalysis, which can provide highly reactive species under mild conditions, represents a potential strategy for such C−C bond cleavage. Here, we report an efficient approach to break lignin C−C bonds using a Z-scheme Ag3PO4−polymeric carbon nitride (PCN) nanocomposite under simulated solar light at room temperature. Various lignin model compounds were converted into aromatic aldehydes with high yields of 66%-95%. Our mechanistic study reveals that the C−C bond cleavage mainly involves an electron-hole coupled photoredox mechanism. The construction of Z-scheme Ag3PO4−PCN heterojunction structure is essential to simultaneously preserve strong reduction and oxidation capability of its components, which is key for the electron-hole coupled Cα−Cβ bond cleavage. The present work offers useful guidance for the design of efficient semiconductors for C−C bond cleavage through band structure engineering.

Electrohydrodynamic (EHD) technology generates airflow without moving parts, making it a reliable solution for various low-energy applications. EHD-based airflow devices enhance airflow patterns, resulting in significant energy savings in air-moving systems. This airflow, also known as ionic wind, is created through Corona discharge, which accelerates electrically charged air molecules in a strong electric field. Currently, EHD's low electrical-to-mechanical energy conversion rate still limit its ability to generate large flow rates. The objective of this study is to enhance the flow rate of EHD-based devices, for applications where EHD can be used as an effective auxiliary technology with low pressure lift, to enhance airflow distribution and circulation. To this end, a novel bladeless air propulsion device is proposed that combines ionic wind with air amplification based on the Coanda phenomenon to amplify EHD-generated flow rates. We assess the performance of the bladeless air propulsion device to generate airflow by investigating fluid dynamics, electrostatics, and energy consumption. We demonstrate the proof-of-concept with an innovative fully-coupled simulation approach for corona discharge and EHD modeling. We explore different design parameters on the conceptual EHD air amplifier, such as the electric potential (10–30 kV) of the discharge electrode, the electrode spacing (5–25 mm), and the channel height (30–150 mm). The studies are performed on a 2D constrained channel flow and a 2D-axisymmetric open space design, respectively. In order to quantify the benefit of air amplification on EHD, the results are benchmarked to a regular EHD setup without amplifying vane as well as to a comparable commercial axial fan. We assess the performance in terms of flow rate per electric power input. Here, the EHD air amplifier in the constrained flow configuration increases the total flow rate by 59% compared to regular EHD and 48% compared to the axial fan for the same electrical energy input. Amplification factors of 16.5–19 are achieved for the constrained configuration and 5.5 to 6.4 for the open space configuration. The predicted energy consumption is 4–17.5 W for the open space configuration, resulting in flow rates up to 140 m3 h−1. These results show that EHD air amplification is a promising way to generate high flow rates with low pressure rise at a low electrical cost, by which it can provide a more sustainable alternative to conventional fans in specific applications., Journal of Cleaner Production, 398, ISSN:0959-6526

Deep-eutectic solvents (DESs) are often considered to be safe, eco-friendly and non-toxic solvents. Due to these green credentials, they are increasingly being studied for application in metal recycling processes. One example is their use as lixiviants for the recovery of cobalt from lithium cobalt oxide (LiCoO2, LCO), which is a common cathode material in lithium-ion batteries. Here, leaching of cobalt is facilitated by reduction of cobalt(iii) to cobalt(ii) in the presence of a reducing agent. However, several recent publications report on the use of DESs as lixiviants at high temperatures (180 °C) without addition of a reducing agent. Typical DESs for these applications are based on mixtures of choline chloride and ethylene glycol (ChCl : EG). Unfortunately, these studies ignore the limited thermal stability of ChCl : EG at high temperatures, which limits the recyclability of this DES. In this work, the drawbacks of using ChCl : EG as the lixiviant in high-temperature ionometallurgical processes are demonstrated. Structural analysis confirmed that ChCl : EG is not stable at 180 °C, forming hazardous and toxic decomposition products such as trimethylamine and 2-chloroethanol. It was hypothesized that choline chloride reduces cobalt(iii) while simultaneously undergoing a radical β-hydrogen abstraction reaction, thereby decomposing to trimethylamine and other degradation products. The main conclusion is that this type of DES should not be used for high-temperature leaching processes due to their limited stability under such conditions. ispartof: GREEN CHEMISTRY vol:24 issue:17 pages:6685-6695 ispartof: location:England status: published

Continuous-flow sorbitol dehydration in liquid water was performed on β zeolite (Si/Al molar ratio = 75) with conversion of 94 and 83 mol % isosorbide yield. This efficiency is due to the three-dimension pore architecture, high specific surface area (520 m2 g–1), and Brønsted acid sites of 69 μmol g–1. The pore size of β zeolite (6.6 × 6.7 Å2) is slightly larger than the cross section of sorbitol and isosorbide and enables an efficient diffusion of the reactant and product to/from the pores. Operation in continuous flow allows rapid dehydration of sorbitol to 1,4-sorbitan, after which the latter got converted to isosorbide. The high yield of isosorbide is attributed to the continuous removal of the formed products from the catalyst surface. Finally, direct isosorbide production from aqueous glucose solution via hydrogenation on Ni catalyst supported on nitrogen-doped carbon, followed by dehydration of the formed sorbitol to isosorbide, was pioneered.

Building integrated photovoltaic (BIPV) is a key concept for the realisation of sustainable buildings. Despite the progress in BIPV modelling, the use of sensitivity analysis (SA) is still scarce in the BIPV literature. SA can help the modeller to identify which model inputs influence the model outputs the most. This paper presents a simulation framework that combines global SA methods with a multi-physics BIPV model. The analysis focuses on the performance of naturally ventilated BIPV facade elements (cell temperature and power). Building performance indicators, such as the total heat flux to the building interior and the building wall temperature, are also analysed. Inputs to the SA include convective heat transfer coefficients, cavity airflow rate, and weather conditions. As expected, the SA results were found to be highly dependent on the range selected for the inputs. For a narrow variation in weather conditions, the exterior convective heat transfer coefficient was identified as the input with the strongest influence on the BIPV performance. Results also showed that cavity ventilation becomes more important as the exterior convective heat transfer decreases. These findings indicate the need for accurate models to represent exterior convective heat transfer in BIPV facades and corroborate the importance of cavity ventilation.

Summary Habitat loss, fragmentation, and degradation impacts are the most direct threat to global biodiversity. In this Primer, we discuss how these three forms of habitat transformation are inextricably intertwined, and how their effects on biodiversity and ecosystems are often context specific. We draw on recent analyses that have explored this context-dependence directly to discuss how local-scale impacts of habitat transformation are mediated by biogeographic-scale variation in evolutionary histories and species’ geographic ranges. We also discuss how changes to ecosystem functions and services in modified habitats can be just as context-dependent—and how these changes are further obscured by high levels of ecological redundancy in species functions, which can confer resilience to habitat transformation. To avoid the impending extinction of millions of species, it is crucial that the impacts of habitat transformation are mitigated through a combination of preventing further habitat loss while simultaneously extending and repairing the habitats that remain.

Abstract The state of the art for the recovery of metals from steel industry by-products using hydrometallurgical processes is reviewed. The steel by-products are different slags, dusts, and sludges from a blast furnace (BF), basic oxygen furnace (BOF), electric arc furnace (EAF), and sinter plant, as well as oily mill scale and pickling sludge. The review highlights that dusts and sludges are harder to valorize than slags, while the internal recycling of dusts and sludges in steelmaking is inhibited by their high zinc content. Although the objectives of treating BF sludges, BOF sludges, and EAF dust are similar, i.e., the removal of zinc and the generation of an Fe-rich residue to be returned to the steel plant, these three classes of by-products have specific mineralogical compositions and zinc contents. Because wide variations in the mineralogical composition and zinc content occur, it is impossible to develop a one-size-fits-all flow sheet with a fixed set of process conditions. The reason for the interest in EAF dust is its high zinc content, by far the highest of all steel by-products. However, EAF dust is usually studied from the perspective of the zinc industry. There are not only different concentrations of zinc, but also variations in the all-important ZnO/ZnFe2O4 (zincite-to-franklinite) ratio. In many chemical processes, only the ZnO dissolves, while the ZnFe2O4 is too refractory and reports to the residue. It only dissolves in concentrated acids, or if the dust is pre-treated, e.g., with a reductive roasting step. The dissolution of ZnFe2O4 in acidic solutions also brings significant amounts of iron in solution. Finally, due to its high potassium chloride content, sinter-plant dust could be a source of potassium for the fertilizer industry. Graphical Abstract

The adverse effects of humans on the environment are growing every day. "Ecological footprint" (EF) is related to the Sustainable Environment and measures the impact of human activities on the environment. The reduction of EF has become a critical issue. This research aims to determine the EF awareness of consumers. The research sample consists of 404 consumers residing in the Ganja province of Azerbaijan. The "ecological footprint awareness survey" has been used as a data collection tool. The collected data were analysed with the SPSS 24.0 package program. The variables of the research were gender, educational status, place of residence, occupation, and income. Research has shown that the highest consumer awareness of EF was in food and transportation, and the lowest awareness was in water consumption. There was no statistically significant difference by gender. When the resident effect was examined, EF water consumption awareness was significantly higher among those living in the town than those living in the city. Consumers with middle school and university degrees were more conscious of their energy consumption levels. By profession, civil servants, farmers and housewives exerted higher environmental awareness than other groups examined. Finally, the income variable showed that higher-income consumers were more aware of the food, energy, and water consumption related matters.

Utilizing electricity from renewable resources is very attractive to decrease the dependence on fossil fuels. As a result, hybrid power systems are gaining more attention. This paper focuses on the optimal design and dynamic simulation of renewable-based, hybrid standalone power systems. The designed system is able to meet the energy need of a building with 5 kW peak electricity demand. Both the technical and economic feasibility of the system was investigated under various climatic conditions of Turkey. Diesel fuel consumption, energy cost and annual CO2 emissions were estimated and compared with the diesel generator-only system. A parametric analysis was also conducted to understand the impact of the capacity of the PV array, wind turbine and the battery on the CO2 emissions and the levelized cost of energy. The system in each location was optimized based on the minimum energy cost and CO2 emissions. (C) 2020 Elsevier Ltd. All rights reserved.

Despite the rapid development of perovskite solar cells (PSCs) toward commercialization, the toxic lead (Pb) ions in PSCs pose a potential threat to the environment, health and safety. Managing Pb via recycling represents a promising approach to mitigating its toxicity. However, managing Pb from commonly used organic solvents has been challenging due to the lack of suitable Pb adsorbents. Here, we report a new adsorbent for both separation and recovery of Pb from PSC pollutants. The synthesized iron-incorporated hydroxyapatite possesses a strongly negatively charged surface that improves electrostatic interaction through surface-charge delocalization, thus leading to enhanced Pb adsorption. We demonstrate the feasibility of a complete Pb management process, including the purification of Pb-containing non-aqueous solvents below 15 parts per 109, a level compliant with the standards of the US Environmental Protection Agency, as well as recycling of 99.97% of Pb ions by forming lead iodide. The most-efficient solar cells use Pb-based halide perovskites; however, their toxicity poses environmental and health risks. Here, the authors report an adsorbent that allows for sustainable Pb management in these devices.

The selective conversion of lignin or lignin-derived products into bulk chemicals is the foremost challenge for near-future lignocellulosic biorefineries. This study investigates the production of ...

Within the framework of metal separations and solvent extraction, chloride media are among the most studied systems. Bromide and iodide media have received much less attention, but can allow a diff...

Made available in DSpace on 2020-12-12T01:25:34Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-06-01 The use of protic ammonium ionic liquids (PILs) in the pretreatment of lignocellulosic biomass is a promising alternative to using expensive aprotic ionic liquids such as 1-ethyl-3-methylimidazolium acetate, [Emim][OAc]. In this work, the PIL monoethanolammonium acetate, [MEA][OAc], was used for the pretreatment of sugar cane bagasse. The study investigated changing the acid base ratio (ABR) from 0.1 to 10 and recycling of the solvent. We determined the lignin extraction, lignin recovery, solvent recovery, and enzymatic saccharification yield and compared the performance to that of the pure amine base, monoethanolamine. We found that lignin extraction and glucose release during enzymatic saccharification increased with base (amine) content, reaching up to 84% and 96%, respectively, after 72 h of saccharification for the 0.1 ABR. Up to 97% of the solvent was recovered for the 1.0 ABR. A higher acid content led to increased hemicellulose extraction into the liquid phase and reduced ionic liquid recovery. A partial conversion of the PIL into N-(hydroxyethyl) acetamide was observed after pretreatment, with up to 86% of conversion after the sixth use for the 1.0 ABR. A negative correlation (R2 = 0.96) was found between the acetamide content in the solvent and the saccharification yield. The drop in pretreatment performance was also correlated with a decrease in accumulated lignin recovery and the molecular weight of the isolated lignins. Acetamide formation was reduced when excess base was present. Recycling of the mixture with 0.5 ABR showed that the performance was unchanged (97% saccharification yield) after three uses, although 28% of the mixture was converted into the acetamide. The study shows that protic acetate ILs made from primary amines form an equilibrium with their amide and a low ABR is required in order to maintain high pretreatment efficiency when the PIL is reused. Process and Products Development Department Faculty of Chemical Engineering State University of Campinas (UNICAMP), Av. Albert Einstein, 500 Department of Chemical Engineering Imperial College London Department of Bioprocess and Biotechnology College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780 Department of Bioprocess and Biotechnology College of Agricultural Sciences São Paulo State University (UNESP), Av. Universitária, 3780

This work presents a thermodynamic evaluation of an operating geothermal ORC power plant. The model is realized by using measured data of AFJET geothermal power plant which has 3MWe net power output capacity. Thermodynamic assessment of the system is conducted to see the energy and exergy efficiencies of each component, and the whole plant. Additionally, a parametric study is conducted to understand the effects of various operating conditions on the system performance. Different from previous studies, daily and annual net power output profile of the plant was investigated with considering ambient temperature fluctuations. Results revealed that net power output can drop as significant as 36% from winter to summer months. Also, between nighttime to daytime, the net power expectation may decrease by 5%. The exergy destruction rate of re-injection process constitutes the most significant part (38.1%) of the total exergy destruction of the plant. The conversion and exergy efficiencies of the system are calculated as 11.24% and 39.03%, respectively. Also, to enhance the performance of the plant, an internal heat recovery system is recommended. The analyses show that the implementation of an internal heat recovery system improves the energy and exergy efficiencies of the plant by 15%.

Nonaqueous redox flow batteries (RFBs) based on redox-active organic molecules are regarded as a promising technology for large-scale grid energy storage. 1,4-Diaminoanthraquinones (DAAQs) are particularly interesting as active species because they can have up to five different electrochemically accessible oxidation states, but their practical usability is limited because of their low solubility in commonly used polar organic solvents. We present a DAAQ derivative, 1,4-bis((2-(2-(2-methoxyethoxy)ethoxy)ethyl)amino)anthracene-9,10-dione (Me-TEG-DAAQ), which can be synthesized from inexpensive precursors and overcomes this disadvantage of low solubility. This derivative has a low melting point (25 °C), a concentration exceeding 2.2 mol L–1 in the pure state, and is miscible in any ratio with polar organic solvents such as acetonitrile (MeCN) and 1,2-dimethoxyethane. Cyclic voltammetry experiments show that two anodic and two cathodic one-electron redox transitions are electrochemically accessible and highly reversible, with an interval of 1.8 V between the two inner redox couples and 2.7 V between the two outer redox couples. Proof-of-concept galvanostatic cycling experiments were conducted on dilute solutions of Me-TEG-DAAQ in a simple symmetric electrochemical cell. When only the two inner redox couples are considered, the electrochemical cell can achieve specific capacities close to the theoretical value (2.68 A h L–1), with only limited capacity fading (i.e., 49 W h L–1), and limited capacity fading in an electrochemical cell based on one single active species is unprecedented in the RFB literature. ispartof: ACS Sustainable Chemistry & Engineering vol:8 issue:9 pages:3832-3843 status: published

International Conference on Photovoltaic Technologies (PVCon) -- JUL 04-06, 2018 -- Middle E Tech Univ, Culture & Convent Ctr, Ankara, Turkey, WOS: 000499762300011, In the present study, using a large area roll-to-roll DC magnetron sputtering system deposition of ITO thin films on polyethylene terephthalate (PET) substrates were achieved. In order to investigate the effect of growth conditions on the film properties all through the deposition process, optical emission spectroscopy (OES) analysis have been accomplished in a governable way. The consequences of Oxygen partial pressure and film thickness on electrical, and optical properties of the films were determined. It was shown that the intensity of optical emission peaks are subjected to the discharge power and as well as the O-2/Ar flow ratio. Large area, uniform ITO films with relatively high transparency and low electrical resistivity (R(2)(

The oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-diformylfuran (DFF) using oxygen (1 atm) with a TEMPO and CuCl catalyst system is investigated using a range of imidazolium-based ionic liquids (ILs) and various bases at different HMF substrate loadings (10-50%). This represents the first example of HMF to DFF conversion in ionic liquid media under homogeneous catalysis conditions, revealing dramatic differences in performance between the ILs. In the non-coordinating, hydrophobic ionic liquid, [bmim][NTf2], 90% DFF yield is obtained at 5 mol% catalyst loading after 6 hours at 80 °C at a very high 40% HMF loading. Increasing the temperature to 100 °C leads to a lower yield, attributed to loss of volatile TEMPO from the reaction medium. A system using TEMPO and pyridine immobilized within the ionic liquid [bmim][NTf2] results in selective conversion of HMF to high purity DFF. It also allows the DFF formed to be isolated by sublimation in 81% yield before a further cycle is performed. Subsequent catalyst deactivation is probed by X-ray photoelectron spectroscopy (XPS). Synthesis from fructose in a two-step process achieves a 55% isolated DFF yield. This approach overcomes significant drawbacks previously reported for this transformation, such as solvent toxicity, separation and purification problems as well as the need for high oxygen pressures. Further oxidation of HMF with this system leads to a 62% yield of 5-formyl-2-furancarboxylic acid (FFCA). The separation of this compound can be achieved by sublimation of DFF followed by solvent extraction.

Lithium is becoming increasingly important due to its essential role in lithium-ion batteries. Over 70% of the global lithium resources are found in salt lake brines, where lithium is always accomp...

Muconic acid (MA) is a high value-added dicarboxylic acid with conjugated double bonds, presenting three isomeric forms, i.e., cis,cis-MA, cis,trans-MA and trans,trans-MA. Its production is garnering increased interest owing to its potential as a starting material for the synthesis of value-added products as well as by being a versatile monomer for the production of specialty polymers. This review presents a systematic overview of production and synthesis routes to MA isomers as well as the routes for its final valorization. The production of MA through chemical pathways and the progress developed in the biotechnological pathways will be discussed. Traditional and new processes for achieving successful isomerization into the value-added trans,trans form of MA are also discussed and compared, with their constraints and possible solutions. The valorization of the three different isomers of MA into value-added chemicals such as adipic or terephthalic acids and MA polymers are summarized. Finally, the review concludes with a thorough summary, a practical insights section and an outlook. This work thus offers new perspectives and guidelines to tackle the challenges in MA chemistry, especially when aiming to combine an efficient biotechnological production of MA with its valorization.

In recent years, the work of various research groups has allowed the substitution of the hazardous solvents most widely used in solid-phase peptide synthesis, namely DMF, NMP, DCM, DEE, among others, by several much less hazardous solvents. Indeed, greener alternatives have been found for almost all steps of the process, with the exception of the cleavage of protected peptides from 2-chlorotrityl chloride resin. Here, after careful screening of several of the so-called green solvents, we propose 2% TFA in either anisole or 1,3-dimethoxybenzene as optimal for the cleavage step. The higher boiling point of these solvents compared with the DCM allows the preparation of protected peptides with less risk of premature removal of the most labile protecting groups, such as the Trt of His. Our findings once again evidence the value/versatility of green solvents in strict chemical terms., The work was funded in part by the following: the National Research Foundation (NRF) (# 105892 and Blue Sky’s Research Programme # 120386) and the University of KwaZulu-Natal (South Africa); and the Spanish Ministry of Science, Innovation, and Universities (RTI2018-093831- B-100) and the Generalitat de Catalunya (2017 SGR 1439) (Spain).

Phenol and its derivatives, which naturally occur in lignocellulose, can be considered as a renewable feedstock not only for aromatic, but also for alicyclic compounds, such as primary and N-substituted cyclohexylamines. So far, the latter are mostly produced from non-renewable starting materials like benzene via problematic nitration/reduction or cross-coupling routes. Herein, an efficient reductive amination of phenol with ammonia or amines is demonstrated, for the first time without the need for rare and expensive noble metals and without using any additives. Various supported Ni catalysts were screened and we elucidated the influence of the key parameters, including the acid–base properties of the supporting material. Acquired knowledge was then applied to different phenol–ammonia/amine combinations, resulting in the synthesis of various primary, secondary and tertiary cyclohexylamines in fair to very high yields.

The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) using the η4-(2,3,4,5-tetraphenylcyclopentadienone) ruthenium tricarbonyl precursor of the well-known Shvo catalyst and H2 pressure was established under solvent-free conditions to achieve 100% conversion and 100% selectivity within 5 hours. Kinetic reaction curves were measured in order to deduce the optimal reaction conditions, which were further evaluated by means of density functional theory (DFT) calculations, and compared with catalytic concepts that consume formic acid or isopropyl alcohol as hydrogen donor. Ultimately, this alternative reaction procedure was subjected to a life cycle assessment (LCA) in comparison with the transfer hydrogenation methodologies, in order to verify its contribution towards a practice of environmentally benign chemistry.

A split-anion solvent extraction process was developed for the separation of precious metal ions Au(III), Pt(IV), Pd(II) and Rh(III) from aqueous chloride media using water-saturated ionic liquids. The metal extraction and stripping behavior of the chloride form [A336][Cl], bromide form [A336][Br] and the iodide form [A336][I] of the quaternary ammonium ionic liquid Aliquat 336 were compared. The three ionic liquids extracted Au(III), Pd(II) and Pt(IV) quantitatively in most cases, whereas the co-extraction of Rh(III) was strongly dependent on the acidity and the chloride concentration. Among the studied ionic liquids, [A336][I] achieved the highest separation factors between Pd(II)/Rh(III), Pt(IV)/Rh(III), and Au(III)/Rh(III) at 6 mol L−1 Cl−. Additionally, the selective stripping of the individual metal ions Pd(II), Au(III), and Pt(IV) was only possible from loaded [A336][I] using ammonia solution (NH4OH), sodium thiosulfate (Na2S2O3), and thiourea ((NH2)2CS), respectively. A closed-loop flow sheet was designed for the recovery of the precious metals from chloride media using split-anion extraction with [A336][I]. The integrated process was demonstrated to be suitable for the purification of Rh(III), Pt(IV) and Pd(II) from a complex metal feed such as the leachate of spent automotive catalysts. The ionic liquid-based split-anion extraction process is simple, selective and effective for the sustainable separation of the precious metals, using only one green extractant [A336][I], which can be regenerated for consecutive extraction-stripping cycles.

Industrial ammonia production without CO2 emission and with low energy consumption is one of the technological grand challenges of this age. Current Haber-Bosch ammonia mass production processes work with a thermally activated iron catalyst needing high pressure. The need for large volumes of hydrogen gas and the continuous operation mode render electrification of Haber-Bosch plants difficult to achieve. Electrochemical solutions at low pressure and temperature are faced with the problematic inertness of the nitrogen molecule on electrodes. Direct reduction of N2 to ammonia is only possible with very reactive chemicals such as lithium metal, the regeneration of which is energy intensive. Here, the attractiveness of an oxidative route for N2 activation was presented. N2 conversion to NOx in a plasma reactor followed by reduction with H2 on a heterogeneous catalyst at low pressure could be an energy-efficient option for small-scale distributed ammonia production with renewable electricity and without intrinsic CO2 footprint. ispartof: CHEMSUSCHEM vol:15 issue:10 ispartof: location:Germany status: published

ispartof: JOURNAL OF CLEANER PRODUCTION vol:338 status: published