Resources Conservation and Recycling最新文献

International trade of food and feed is increasing, which may limit nutrient recycling in food systems, to an unknown extent. We examined phosphorus (P) circularity in food systems of 88 main importing countries and 37 main exporting countries for 2000–2018. We inferred P input circularity (P in recycled residues as share of total P inputs), and P output circularity (P in recycled residues as share of total P in residues). Global mean output circularity was 65%, and slightly higher for exporting countries than importing countries. Global mean input circularity for cropland was 77% in importing countries and 62% in exporting countries, suggesting that residues from imported products contributed to P circularity. Our study provide insights in the prospects and mechanisms for increasing P circularity, which may help policy makers to design targeted interventions that minimize the need for synthetic P fertilizer and lower P losses in food systems.

Mitigating methane emissions from the rice paddy in China proves to be one of the most vital approaches to achieving the global methane reduction target, but the heterogeneity and effectiveness of existing methane reduction strategies and the influencing factors of their mitigation effects remain not systematically explored for China. We employed a meta-analysis to evaluate ten identified methane mitigation technologies in China, based on field experiments data. We show the methane mitigation effects vary in descending order, as water-fertilizer coupling management > water management > tillage management > fertilizer management. In particular, the water-fertilizer coupling management could reach a reduction of 67.27 %, which is markedly higher than employing singular practices and eliminates the “trade-off” among individual reduction measures. Overall, the mitigation effects are subject to various factors, such as experimental year, soil pH, and precipitation, leading to varying effectiveness across regions. Intermittent irrigation and alternate wetting and drying irrigation have high abatement potential in southern China, while urea and variety yield better results in northern China. Although China's methane reduction efforts are at the forefront among Asian countries, the potentially exacerbating methane leakage issues due to its increasing import of rice from Southeast Asia deserve a special focus as well.

Solar photovoltaic (PV) waste and resource projections are integral for end-of-life (EoL) management. Addressing gaps in Australian studies, this paper aims to produce improved projections from 2022 to 2050. This study uses up-to-date, location-based installation data, distributed practical lifetime estimates by system size, current literature on market share and material composition over time and recovery rates, and provides a closed loop material analysis. In 2050, cumulative PV waste is estimated at 2,000,000–3,000,000 tonnes for slow, conservative, and realistic forecast installations, though under ambitious installs, waste will be 1–2 times more. Additionally, in 5 years PV EoL silver and aluminium could supply on average 30 % of future PV demand, 50 % in 15 years, and even up to 100 % in 25 years, considering realistic or ambitious forecast installations. These findings seek to assist in establishing sustainable EoL PV management, including the planning of logistics, appropriate recycling methods, consumer-appropriate policy, and the integration of circularity.

Plastic film mulching (PM) and water-saving and drought-resistant rice (WDR) are believed to increase crop yields and decrease CH₄ emissions, respectively. Here, a comprehensive estimation is prepared on how the combination of PM and WDR impacts rice yields, CH₄ and N₂O emissions, global warming potential (GWP), greenhouse gas emission intensity (GHGI), and net economic ecosystem benefits (NEEB). Shifting continuous flooding (CF) into traditional rainfed (TF) and PM decreased CH₄ emissions (35–92 %), GWP (33–91 %), and GHGI (31–88 %). Moreover, PM considerably reduced input costs and GWP costs relative to CF whereas increasing grain yields and yield gains relative to TF, thus promoting NEEB by around 3500 and 6000 CNY ha^–1, respectively. Combining PM with WDR further enhanced NEEB by 935 CNY ha^–1. The findings indicate that PM with the combination of WDR would be a promising strategy for lower greenhouse gas emissions and higher grain yields and economic benefits in rice agriculture.

Multilayer flexible packaging waste (MFPW) represents a critical issue in the field of waste management. The heterogeneous composition of this type of plastic makes its recyclability challenging. In this context, the delamination process appears to be a promising way to recycle the polymers layers separately. However, this process is still limited for a few MFPW.

This work propose an innovative way to improve the delamination process using three surface modification techniques (mechanical and laser microperforation (µP), and abrasion) on the MFPW surface in order to accelerate the diffusion of the dissolving agent. The delamination was tested in a 10 % sodium hydroxide solution at 25ºC.

Under this study, the mechanical µP and the abrasion gave the best results of delamination compared to the laser µP (total delamination in 25 min vs 45 min, respectively). It was concluded that the distance between the microholes was an important factor in both µP techniques.

Due to the scarcity of Li resources and the environmental burden, comprehensive and efficient recycling of spent LiFePO₄ batteries has attracted extensive attention. The existing recycling strategy still has obstacles of low Li recovery efficiency and high consumption of acid and base. The pressure leaching was proposed to extract Li from the spent LiFePO₄ cathode selectively without oxidization. The process is mainly to fix the Fe and P in the residue and the Li into the water phase, reducing the reagent consumption and the burden of subsequent removal of Fe and P. More than 99 % of Li could be extracted into the solution under optimal conditions, and it avoided the entrance of the impurities Al and Ca into the leaching solution. The extraction mechanism indicated that the selective extraction of Li and the precipitation of Fe₃(PO₄)₂‧8H₂O were carried out stepwise. In addition, the leaching solution was used to prepare high-purity Li₂CO₃ products and leaching residue could be applied to produce battery-grade FePO₄. This process puts forward a new approach to recovering Li from spent LiFePO₄ batteries, which has the advantages of high efficiency, reagent cost savings, and easy operation.

Liquid packaging boards are widely used for beverage packaging, but their complex composition poses challenges for recycling. These composites are occasionally recycled through hydropulping. However, this method only allows for partial recovery of the paperboard and produces a reject mixture of aluminium, plastics, and residual paper fiber. This study demonstrates the first process to purify all main components of beverage carton packaging waste derived from a commercial pulp mill using solvent-targeted recycling with multiple green solvents, such as p-cymene and ionic liquids. By utilizing this solvent-based process, all major components from the waste were recycled to their original forms in excellent purity, particularly aluminum—an essential industrial metal typically obtained through energy-intensive methods. Furthermore, the solvents used in our material recycling system can be recycled in high purity and reused in the fractionation process. The recovered paper fiber could be converted to the versatile platform chemical levulinic acid in good yield.

Industrial symbiosis promotes circular economies with environmental and economic benefits. China's 14th Five-Year Plan for Circular Economy Development prioritizes waste recycling and co-processing in cement kilns. This research investigates the advantages of establishing symbiotic relationships between industrial park and cement kiln to address industrial hazardous waste (IHW) challenges. Using life cycle assessment and net cost analysis with system expansion, we quantify environmental and economic disparities between industrial park-cement symbiosis and non-symbiosis scenarios. The symbiosis mode reduces carbon emissions by 11 % and saves 8 % cost annually compared to non-symbiosis. Optimizing upstream waste fine management enhances calorific value and fossil fuel substitution, increasing CO₂ reduction and economic benefits but raising acidification and terrestrial ecotoxicity. Upstream-downstream cooperation is vital for systematic environmental relief. Employing carbon capture and ultra-low emissions in cement kilns mitigates environmental impact. These findings guide policies for better hazardous waste management, fostering a "waste-free city" and circular economy.

Affected by climate change, food systems face enormous challenges of mismatch between competition for resources and nutritional demands. More than one third of food system emissions come from pre- and post-production. Research on emissions from food supply chains is crucial for building sustainable food systems and mitigating climate change. Rice is a major staple crop for mitigating emission risks in the food system. Based on the GHG emission accounts of rice supply chain in China from 2000 to 2020, this study analyzes the emission characteristics of rice supply chain during production, consumption, and trade, then elucidates the inter-regional transfers and inter-sectoral flows of rice emissions. This study found that non-CO₂ GHGs at the production side contributes 78.56 % of total emissions of rice supply chain. Emissions of rice supply chain showed a promising downward trend of China, with the gravity center moving northward. Emission risks of inter-regional transfers were lower in the middle and lower reaches of the Yangtze River Plain, while higher in the Northeast China Plain. Emissions of inter-sectoral flows predominantly manifest within the agriculture sector in the major rice producing areas or between the agriculture and its downstream sectors. Accordingly, this study concludes potential paths contributing to emission reduction along rice supply chain of China by improving the relationships of production and inter-sectoral and inter-regional trade. This study can provide references for building sustainable food systems under climate change.