High-efficiency and economical uranium extraction from seawater with easily prepared supramolecular complexes.

Developing effective adsorbents for uranium extraction from natural seawater is strategically significant for the sustainable fuel supply of nuclear energy. Herein, stable and low-cost supramolecular complexes (PA-bPEI complexes) were facilely constructed through the assembly of phytic acid and hyperbranched polyethyleneimine based on the multiple modes of electrostatic interaction and hydrogen bonding. The PA-bPEI complexes exhibited not only high uptake (841.7 mg g-1) and selectivity (uranium/vanadium selectivity = 84.1) toward uranium but also good antibacterial ability against biofouling. Mechanism analysis revealed that phosphate chelating groups and amine assistant groups coordinated the uranyl ions together with a high affinity. To be more suitable for practical applications, powdery PA-bPEI complexes were compounded with sodium alginate to fabricate various macroscopic adsorbents with engineered forms, which achieved an extraction capacity of 9.0 mg g-1 in natural seawater after 50 days of testing. Impressively, the estimated economic cost of the macroscopic adsorbent for uranium extraction from seawater ($96.5 âˆ¼ 138.1 kg-1 uranium) was lower than that of all currently available uranium adsorbents. Due to their good uranium extraction performance and low economic cost, supramolecular complex-based adsorbents show great potential for industrial uranium extraction from seawater.

VOC and IVOC emission features and inventory of motorcycles in China.

How did the motorcycle emissions evolve during the economic development in China? To address data gaps, this study firstly measured the volatile organic compound (VOC) and intermediate-volatility organic compound (IVOC) emissions from motorcycles. The results confirmed that the emission control of motorcycles, especially small-displacement motorcycles, significantly lagged behind other gasoline-powered vehicles. For the China IV motorcycles, the average VOC and IVOC emission factors (EFs) were 2.74 and 7.78 times higher than the China V-VI light-duty gasoline vehicles, respectively. The notable high IVOC emissions were attributed to a dual influence from gasoline and lubricating oil. Furthermore, based on the complete EF dataset and economy-related activity data, a county-level emission inventory was developed in China. Motorcycle VOC and IVOC emissions changed from 2536.48 Gg and 197.19 Gg in 2006 to 594.21 Gg and 12.66 Gg in 2020, respectively. The absence of motorcycle IVOC emissions in the existed vehicular inventories led to an underestimation of up to 20%. Across the 15 years, the motorcycle VOC and IVOC emission hotspots were concentrated in the undeveloped regions, with the rural emissions reaching 5.81-10.14 times those of the urban emissions. This study provides the first-hand and close-to-realistic data to support motorcycle emission management and accurate air quality simulations.

Carbon Trading in China Reduces the Dependence of Household Waste Electrical and Electronic Equipment Recycling on Government Subsidies.

China's enterprises of waste electrical and electronic equipment (WEEE) recycling suffer from low profitability that is highly dependent on government subsidies. This low economic gain impedes the sustainable growth of China's WEEE-recycling sector and also adds to the government's financial burden. Prior life-cycle studies have approved the carbon reduction potentials or net carbon credit of recycling WEEE. However, policymakers fail to know whether the revenue from selling carbon credits can offset the government's financial subsidy. We performed life-cycle and cost-benefit analyses for a case recycling enterprise that processes six categories of household appliances. The results show that the reduction potentials of greenhouse gases range from 930-3450 kgCO2e by recycling per ton of household appliances and materials substitution. The recycling enterprise would gain extra revenue ranging from 32 to 160 RMB per ton of appliance if the carbon credits were sold at China's current carbon price, i.e., 45-60 RMB tCO2e-1. Recycling waste refrigerators exhibits the highest carbon revenue, offsetting 6-17% of the government's financial subsidy. Microcomputers, by contrast, indicate the lowest carbon revenue, equivalent to 1-3% of its highest government subsidy. For each household appliance category, when the carbon price reaches 270-600 RMB tCO2e-1, selling carbon credits can fully offset the government's financial subsidy. Constrained by the processing capacity of the case enterprise, optimizations for appliance-recycling composition contribute a 15-25% profit growth to the current economic gains. Interpreting the specific profit depends on the predefined scenarios of carbon price and the substitution rate of the regenerated materials for the virginal ones. Our findings show that raising the profitability of WEEE recycling enterprises through the carbon trading policy contributes to the sustainable growth of China's WEEE-recycling sector while alleviating the government's financial burden.

From full life cycle assessment to simplified life cycle assessment: A generic methodology applied to sludge treatment.

Life cycle assessment is widely used to evaluate sludge treatment methods. However, detailed life cycle assessment is time-consuming and resource-intensive. In addition, the complex characteristics of sludge and the variety of treatment methods increase the difficulty of sludge treatment life cycle assessment. There is an urgent need to develop simplified life cycle assessment models to allow rapid decision-making. This study proposes a simplified method of sludge treatment life cycle assessment based on logistic regression analysis. The simplified model relies on the total environmental impact and very few or even a single input parameters. Contribution and data quality analysis were introduced to identify key input parameters and to obtain model training data. The method was eventually applied to traditional sludge treatment methods, showing that it can quickly and accurately predict environmental impact. Representative analysis showed that the model would be affected by technology and energy structure modification. It is hoped that this study will provide a reference and new perspectives for a simplified life cycle assessment of sludge treatment.

Towards the carbon neutrality of sludge treatment and disposal in China: A nationwide analysis based on life cycle assessment and scenario discovery.

Motivated by the carbon neutrality target, strategic planning for a low-carbon transition of sludge treatment and disposal in China is challenging due to the unpredictability of technical, regional, socioeconomic, and political factors affecting greenhouse gas (GHG) emissions. This study combines the use of a Life Cycle Assessment and the Patient Rule Induction Method, accounting for possibilities that could achieve net-zero carbon emissions by exploring multiple plausible future profiles of sludge treatment and disposal. Results show that reducing sludge landfill and increasing anaerobic digestion are effective methods to facilitate GHG reduction. Achieving carbon neutrality is closely linked to developing a cleaner electricity mix. Based on a cascaded scenario analysis considering regional differences for 31 Chinese provinces, results demonstrated a maximum cumulative reduction potential of 371 Mt CO2 equivalents from 2020 to 2050, equal to 59.84% of the business-as-usual scenario. Together with GHG reductions, terrestrial acidification and ecotoxicity as well as freshwater ecotoxicity are synergistically reduced. However, the shifting environmental burden results in freshwater eutrophication, human toxicity, marine ecotoxicity, marine eutrophication, and photochemical oxidant formation. This study presents a novel method for systematically identifying possible future development paths toward carbon neutrality. The findings may support policy designs for achieving target carbon reduction effects for sludge disposal.

The impact of cross-shareholding under different power structures considering green investment and green marketing.

Cross-shareholding has played an important role in strengthening strategic synergy among enterprises, but its impact on the green development of enterprises is unclear. In this paper, we construct an analytical framework that includes a manufacturer and a retailer to explore the impact of cross-shareholdings under different leaderships on green supply chain operational decisions and profits, in which the manufacturer invests in green technologies and the retailer conducts green marketing. By constructing and solving the game model of manufacturer-led and retailer-led before and after cross-shareholding, it is found that after cross-shareholding, the product's green level and the retailers' marketing level are improved. For supply chain leaders, cross-shareholdings always increase their profits. Only when the follower holds the leader's shares no more than a certain value, cross-shareholding will increase the total profit of the supply chain. In addition, we obtain the optimal decisions and profits of the supply chain in the integrated situation and design two-part pricing contracts to achieve cross-shareholding supply chain coordination. The results of this paper can provide theoretical guidance and decision support for enterprises interested in using cross-shareholding to improve supply chain performance.

Study on the Spatial Interaction between Urban Economic and Ecological Environment-A Case Study of Wuhan City.

In order to study the interactive relationship between urban economic and ecological environment, taking Wuhan as an example, Landsat and MODIS remote sensing satellite data and social and economic data were fused with multisource data, and multidimensional indicators were selected to construct the comprehensive evaluation index system of urban economic and ecological environment. The weights were determined by combining subjective and objective methods. Then, the decoupling elasticity coefficient method and spatial autocorrelation model were used to evaluate the dynamic relationship and spatial relationship between economic development and ecological environment in Wuhan from 2014 to 2020. The results showed that there was an interaction between the urban economic and the ecological environment in Wuhan. The ecological level index had a spatial effect, the adjustment of industrial structure had a positive effect on the improvement of the ecological level, and the improvement of the ecological level was also helpful to promote economic development. The typical districts of Huangpi District, Xinzhou District, Jiangxia District, Hannan District, Caidian District, and Hongshan District had superior location and ecological advantages, as well as high development potential. Lastly, on the basis of the empirical analysis results, policy suggestions are made from four aspects: regional differentiated construction, green development, energy consumption, and wetland construction.

Scenario analysis on optimal farmed-fish-species composition in China: A theoretical methodology to benefit wild-fishery stock, water conservation, economic and protein outputs under the context of climate change.

Fish production from aquaculture and wild captures suffers from the rising risk of climate change. This impacts the livelihoods of fishers and fish farmers by shrinking wild fishery stocks, inland water scarcity, and consequent declines in economic and protein productions. China, feeding the most fish of the world with water-intensive crops, faces challenges of water scarcity but still be premature in developing strategies to adapt to climate change. Here, focusing on methodology development, we quantified the water footprint of fish-farming and economic and protein productions in the baseline year 2014. Then, 29 scenarios of farmed-fish-species composition (FFSC, i.e., tons of each farmed fish species) were developed for the target year 2020. The baseline 2014 shows that fish farming generates an average of 150 billion m3 of water footprint, 4.70 million tons of protein, and 263 billion RMB of economic output (~39 billion USD). Uncertainty optimizations were conducted to generate the optimal FFSC solutions that show a potential to increase fish production by 22%, economic and protein output by 18% and 29%, respectively and simultaneously lower water footprint by 22% to the maximum extent. Nine scenarios that lower wild fishery captures were further examined, with optimal FFSC solution that encourages aquaculture of Grass carp, Bighead Carp, and Silver Carp, and discourages Black carp, Tilapia, Crucian carp, Sea bass, and Wuchang bream. From a methodology aspect, this study pulls back policymakers from only focusing on the short-term economic interest of fish-farming and persuades them to rethink long-term adaptive strategies to climate change from multiple sustainable dimensions.

Efficient vanillin biosynthesis by recombinant lignin-degrading bacterium Arthrobacter sp. C2 and its environmental profile via life cycle assessment.

Vanillin is a natural flavoring agent that is widely used in the bioengineering industry. To enable sustainable development, joint consideration of bacterial performance and negative environmental impacts are critical to vanillin biosynthesis. In this study, a cold shock protein (csp) gene was upregulated for maintaining stable growth in Arthrobacter sp. C2 responding to vanillin and cold stress. Furthermore, the recombinant strain C2 was constructed by simultaneously deleting the xylC gene encoding benzaldehyde dehydrase and overexpressing the pchF gene encoding vanillyl alcohol oxidase and achieved a maximum vanillin productivity of 0.85 mg/g DCW/h with alkaline lignin as the substrate. Finally, this process generated an environmental impact value of 25.05, which was the lowest environmental impact achieved according to life cycle assessment (LCA). Improvement strategies included reducing electricity consumption and replacing chemicals. This study achieved the development of an effective strategy, and future studies should focus on precise vanillin biosynthesis methods for large-scale application.

Resource recovery in life cycle assessment of sludge treatment: Contribution, sensitivity, and uncertainty.

This study focused on the resource recovery of sludge treatment by quantifying the environmental contributions, identifying the influential factors, and comparing different scenarios. Life cycle assessment (LCA) of sewage sludge treatment was carried out to estimate the environmental impacts of six scenarios: (1) co-digestion of sludge and food waste; (2) co-gasification of sludge and woody waste; (3) co-incineration of sludge and used oil; (4) landfilling; (5) incineration; and (6) anaerobic digestion combined with incineration. Results demonstrate that the resource recovery had a substantial contribution to the environmental performance of the sludge treatment, while the degree of contribution was largely affected by various treatment scenarios and diverse impact categories. To gain deep insight into the parameters related to resource recovery, sensitivity analysis was performed to investigate the influence of the parameters on the LCA results, including the organic content, conversion efficiency of organic matter to methane, and other energy conversion efficiencies. After integrating the inventory variation of those parameters into the decision process via the Monte Carlo simulation, results indicate that no obviously superior scenario could be identified. Conversely, when parameter uncertainty was not considered, co-gasification of sludge and woody waste exhibited the most preferable environmental performance. Overall, this study demonstrates that considering the parameter uncertainty of resource recovery will contribute to a more transparent evaluation process, but will inevitably increase the complexity of the decision-making process based on LCA results because it is difficult to determine a sludge treatment scenario that decisively outperforms the others.

Low-Temperature Synthesis of Amorphous FePO4@rGO Composites for Cost-Effective Sodium-Ion Batteries.

The dramatic growth of the sodium-ion battery market evokes a high demand for high-performance cathodes. In this work, a nanosized amorphous FePO4@rGO composite is developed using coprecipitation combined with low-temperature hydrothermal synthesis, which registered a surface area of 179.43 m2 g-1. The composites maintain three-dimensional mesoporous morphology with a pore size in the range of 3-4 nm. Uniform distribution of amorphous FePO4 allows a reversible capacity of 175.4 mA h g-1 at 50 mA g-1 while maintaining a stable cycle life of 500 cycles at 200 mA g-1. The amorphous FePO4@rGO, obtained by energy-efficient synthesis, significantly improved the rate performance compared to the crystalline material prepared at high temperatures. Cyclic voltammetry tests reveal that the fast reaction kinetics can be attributed to the pseudocapacitive behavior of the electrode. In addition, we demonstrated the promise of FePO4@rGO cathodes for low-temperature sodium-ion batteries.

Environmental Burdens of China's Propylene manufacturing: Comparative life-cycle assessment and scenario analysis.

China's propylene feedstock shifts from oil to imported cheap propane and local coal. However, the associated environmental loads of this feedstock change have seldom been investigated for China's propylene industry. Herein, environmental impacts of the four typical propylene production routes, coal to olefin (CTO), propane dehydrogenation (PDH), steam cracking (SC), and catalytic cracking (CC) process, were compared by life-cycle-assessment (LCA) methodology. Two metrics, midpoint environmental impacts (including nine indicators) and the comprehensive index of energy conservation and emission reduction (ECER), were adopted for this evaluation. The midpoint-impact indices show the trade-offs across the nine environmental dimensions. Thus, it is not easy to rank the environmental advantage of the four production routes. The ECER indices indicate the highest environmental loads in the CTO process, followed by PDH and the comparable SC and CC routes. Raw materials consumption dominates the environmental burden generations of the PDH, SC, and CC routes. Scenario analysis shows that feedstock shift and capacity growth jointly increase the environmental burdens of China's propylene industry by 27-66% in 2025 and 60-111% in 2030, relative to the 2018 baseline. Notably, global-warming potential inevitably increases due to replacing the conventional oil-fed SC/CC capacity either by coal-fed CTO or by propane-fed PDH route. The findings suggest that the feedstock shift of the propylene industry deserves close attention to promote the environmental sustainability of the Chinese chemical manufacturing industry.

Identifying environmental hotspots and improvement strategies of vanillin production with life cycle assessment.

Vanillin, an important aroma chemical, can be synthesized through industrial oxidation processes and biotechnological processes. Studying the environmental impacts of synthetic vanillin production processes is fundamental to making these processes feasible and sustainable; however, few studies have focused on such analyses. This study involved performing a life cycle assessment (LCA) to evaluate multiple industrial synthesis and biosynthesis processes for producing synthetic vanillin. The results indicated that human toxicity potential (HTP) appeared to be the most affected indicator among all the impact categories considered. The dominant drivers of the HTP of the vanillin synthesis process were electricity consumption and ultrapure water consumption. Improvement strategies were then proposed to investigate the possibility of reducing the environmental burdens created by vanillin synthesis. Natural gas power generation was determined to be the best choice for replacing traditional coal-fired power generation, thus reducing the negative impacts of these processes on the environment. The best ways to reduce chemical consumption were to recover organic solvents and to replace ultrapure water with industrial or distilled water. All these improvement strategies were demonstrated to be able to effectively reduce the HTP. In addition, suggestions for evaluating scaled-up vanillin production, increasing the LCA coverage to include technological advancements in biosynthesis techniques, and introducing cost-benefit analysis into the LCA were discussed.

Cooperative grassland management practices promoted by land tenure system transformation benefit social-ecological systems of pastoralism on the Qinghai-Tibetan plateau, China.

China has recently implemented the latest rural land tenure reform with the "Separating Three Property Rights" as non-tradable land ownership, non-tradable land contracting right and tradable land use right, leading to a dramatic change in grassland management strategies in vast pastoral areas. However, the impact of this new reform on grassland management practices is widely debated by scholars and policy analysts. To identify the factors impacting the pastoralists' choice of grassland management practice and the social, economic and ecological benefits derived from different grassland management practices, we conducted a field survey of pastoralists (n = 259) in 7 counties on the Qinghai-Tibetan Plateau. The results showed that respondents' gender, grassland area, scale and location of the village, grassland condition perception significantly exerted positive influence on pastoralists' willingness to participate in cooperative grassland management practices, while grassland fence and urban life expectation negatively influenced the willingness. We found that cooperative grassland management practices led to significantly higher household incomes, more equal gender relationships and better-managed grasslands than individual ones. In spite of this, there were still a large number of pastoralists who chose individual grassland management practices due to their long-term customary operations. In conclusion, this new rural land tenure reform has facilitated pastoralists' choice for diverse grassland management practices and the promoted voluntary large-scale cooperative grassland management practices benefit the social-ecological system of pastoralism.

Modeling the oxygen-depleting potential and spatially differentiated effect of sewage organics in life cycle assessment for wastewater management.

Excessive organic emissions measured as chemical oxygen demand (COD) have caused serious regional water pollution i.e. the widespread malodorous black rivers in China. Assessing the optimum treatment strategies is generally a complicated work involving sophisticated trade-offs across regional improvement and global sustainability. Life cycle assessment (LCA) is a promising tool to support such trade-offs, but it appears difficult to comprehensively reflect the direct impact of high-COD wastewater. This is because, the current LCA framework only highlights the effect of nutrients as a representative eutrophication indicator. To address this issue, this study extends the LCA framework by defining a new COD category to characterize the oxygen-depleting processes associated with development of characterization factors and models. By combining water quality model, the modeling scheme is shown capable of converting dynamic effects of COD on the receiving water into the spatially differentiated impact-assessment results. Upon a descriptive case, we also illustrate that the modeling scheme can construct different environmental situations by varying the embedded variables. This enables the refined investigations of the paradigm shift in wastewater treatment, which contributes to the avoidance of "one-size-fits-all" solution identified without considerations of environmental sustainability. Last, we discuss the ways to further refining the modeling scheme to make it applicable in more cases of water pollution.

Engaging multiple weighting approaches and Conjoint Analysis to extend results acceptance of life cycle assessment in biological wastewater treatment technologies.

Environmental impacts of biological wastewater treatment technologies (BWTTs) can be evaluated by life cycle assessment (LCA). However, very few efforts have been made to expand the ranges of results acceptance and promote stakeholders to participate in the results analysis. To facilitate the evaluation reaching more wide and deep understanding, this study proposed to employ multiple weighting methods and the Conjoint Analysis. To investigate the feasibility, an illustrative case of a bioaugmented constructed wetland was carried out. Weighting results indicated that appropriate improvement strategies could be obtained from synthesizing the similarities and differences of LCA results due to different weighting methods employed. Meanwhile, application of Conjoint Analysis was conducive to the communication between LCA practitioners and BWTTs stakeholders. In a simulated decision-situation, this study found that the decision-making process of stakeholders could be clearly derived to indicate how stakeholders would take trade-offs and make choices based on analyzing LCA outcome.

Set organic pollution as an impact category to achieve more comprehensive evaluation of life cycle assessment in wastewater-related issues.

For wastewater-related issues (WRI), life cycle assessment (LCA) is often used to evaluate environmental impacts and derive optimization strategies. To promote the application of LCA for WRI, it is critical to incorporate local impact of water pollutants. Organic pollution, a main type of water pollution, has not been given much consideration in current LCA systems. This paper investigates the necessity of setting a regionalized impact category to reflect the local impact of organic pollution. A case study is conducted concerning an upgraded wastewater treatment plant (WWTP) in China, which is assumed to meet different sewage control strategies. Chemical oxygen demand (COD) is selected to represent the organic pollution and treated as an individual impact category. CML 2002 is used to quantify the environmental impacts of different strategies. Results show that abnormal LCA results are generated with the traditional eutrophication impact category, and after the introduction of COD, more reasonable LCA results are obtained, making the entire comparison of different control strategies more meaningful and compelling. Moreover, BEES, Ecovalue 08, and Chinese factors are adopted here as different weighting methods. Different weighting results exhibited various trade-offs for the increasingly strict control strategies; the results of BEES and Ecovalue08 underlined the potential environmental burden, but the results of Chinese factors only emphasized the local environmental improvement. It is concluded that setting regionalized impact category for organic pollution can make LCA results more reasonable in wastewater treatment, especially in evaluating Chinese cases because of the serious water pollution caused by large quantities of COD emission.

Evaluation of bioaugmentation using multiple life cycle assessment approaches: A case study of constructed wetland.

Bioaugmentation is a promising technology to enhance the removal of specific pollutants; however, environmental impacts of implementing bioaugmentation have not been considered in most studies. Appropriate methodology is required for the evaluation from both in-depth and comprehensive perspectives, which leads to this study initiating the application of life cycle assessment (LCA) of bioaugmentation. Two LCA methods (CML and e-Balance) were applied to a bioaugmentation case with the aim of illustrating how to evaluate the environmental impacts of bioaugmentation from different perspectives based on the selection of different LCA methods. The results of the case study demonstrated that the LCA methods with different methodology emphasis produced different outcomes, which could lead to differentiated optimization strategies depending on the associated perspectives. Furthermore, three important aspects are discussed, including coverage of impact categories, the selection of characterization modeling for specific pollutants, and the requirement of including economic indicators for future investigation.