Qingxin Zheng

Traditional disposal methods of biomass and plastic waste, such as landfill, combustion, and compost, no longer meet the requirements of carbon reduction, carbon neutrality, and sustainable society due to low utilization efficiency and severe pollution. As a green, efficient and environmentally-friendly method, hydrothermal technology has been paid much attention to and has already been applied to recycle or reuse various plastic and biomass wastes. No matter for the single or mixed type of wast

As one of the most important lithium-ion battery cathode materials for electric vehicles, LiMn2O4 (LMO) cathode material was used as the feedstock of metal recovery in this study. Through a hydrothermal treatment with citric acid (0.3 mol/L), Li and Mn ions were completely leached from a commercial LMO cathode material at 120 °C for 2 min. More importantly, simultaneously with complete leaching of Li and Mn ions from LMO, the Mn component was precipitated and separated as a Mn–citrate complex by

Continuous hydrothermal leaching of LiCoO₂ cathode materials with citric acid was firstly achieved using a customized flow system.

Glycine was applied as the leachant for the hydrothermal leaching of lithium-ion battery (LIB) cathode materials, LiCoO2 and LiNiO2, at 90–180 °C for 5–90 min. LiCoO2 was completely leached at 180 °C for 30 min. It was revealed that Co(III)–glycine complex formed first and was gradually reduced to Co(II)–glycine complex. Compared to LiCoO2, LiNiO2 required a lower temperature and shorter time for complete leaching. Different from using inorganic acids or organic acids like citric acid, pH values

This review summarized the valuable works on the extraction technologies using pure liquefied dimethyl ether (DME) as the organic solvent. DME is a colorless gas with a slight ether-like fragrance at room temperature and pressure. Due to some special properties, such as the strong ability for extracting organic compounds and water, high extraction rate, cheap price, low extraction temperature, and energy consumption, environmental friendliness, safety, and good compressibility, the application o

Abstract Multi‐layer plastic films are widely used in various fields especially for packaging, but due to complex composition, it is very difficult to recover single‐material polymers or high‐purity monomers from them after usage. In this study, we proposed a hydrothermal process for recycling PET/PE (PET: Polyethylene terephthalate; PE: Polyethylene) films. PET can be hydrolyzed to monomers of terephthalic acid (TPA) and ethylene glycol (EG). Using a hydrothermal system equipped with two filter

Here, Ni, Co, and Li ions in the leachate obtained from commercial LiCoO2/LiNiO2 cathode materials by hydrothermal leaching with citric acid were precipitated and separated in order using a series of precipitants, dimethylglyoxime (DMG), (NH4)2C2O4, and Na3PO4, respectively. The parameters including the pH value, precipitant amount, and reaction temperature were optimized during the metal separation step. Finally, the recovery rates of Ni, Co, and Li were 97.2, 96.1, and 94.1%, respectively, wit

High-quality carbonaceous microspheres were produced directly from wood sawdust by a novel hydrothermal method, combining hydrothermal carbonization and hydrothermal extraction.