Mild and green dissolution of lithium cobalt oxide (LCO) with high efficiency is challenging. Here, novel DESs based on poly­(ethylene glycol) 200 and p-toluenesulfonic acid monohydrate are designed and found to dissolve LCO with nearly a 100% leaching efficiency at 100 °C within 24 h, which is much higher than the leaching efficiency by DESs in the reported references. The dissolution mechanism investigation shows that the interaction between DESs and LCO is a physical process. This work provides a new strategy for the mild and efficient dissolution of LCO by cheap and green solvents.

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High efficient and sustainable conversion of CO2 into quinazoline-2,4(1H,3H)-dione at room temperature and atmospheric pressure is challenging. Deep eutectic solvents (DESs) are considered as the green solvents of the 21st...

Rare earth elements are a nonrenewable and important strategic resource, and China is rich in these elements. However, the substantial exploitation of these resources has caused the migration, diffusion, transformation and accumulation of pollution sources, which in turn has a profound impact on the ecological environment of mining areas. Accurate evaluations of resource and environmental carrying capacity (RECC) are important for the green development of mining areas. In this paper, the fuzzy comprehensive evaluation method based on the combination of the AHP (Analytic Hierarchy Process) and entropy methods is used to study the RECC of mine areas in terms of both support capacity and pressure. The Bayan Obo mine in Inner Mongolia, the Longnan mine in Jiangxi, the Weishan mine in Shandong, the Mianning mine in Sichuan, the Pingyuan mine in Guangdong, and the Chongzuo mine in Guangxi, which are typical representative mines, were selected for a horizontal comparison. The results show that, with the exception of the Bayan Obo mine, the support index was greater than the pressure index in terms of mining and human activities in all mining areas. The RECC index ranked order for the mining areas was Bayan Obo > Longnan > Mianning > Pingyuan > Weishan > Chongzuo. In addition, an obstacle degree model was used to identify and extract the main factors affecting the ecological quality of the mine sites. The ratio of investment in environmental pollution control to GDP was the most important factor, of all factors, which limited the improvement in the mine support index. Through the above research, we identified the main factors affecting the ecological carrying capacity of each mining area, providing a scientific basis for formulating corresponding environmental regulations and reducing the environmental pollution caused by rare earth mining.

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