Based on a combination of spontaneous lithium migration and targeted electrically-driven lithiation, a two-step resting-output current process was conducted to directly regenerate retired LiFePO4 cathode, which can reduce energy consumption and environmental pollution.

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Interactions of dissolved organic matter (DOM) from landfill leachate with clays could affect significantly the fate of hydrophobic organic compounds (HOCs) in soils. The complexes of montmorillonite (MT) and kaolinite (KL) with DOM extracted from landfill leachate were prepared under controlled conditions, termed CMT and CKL, respectively. The bare clays and their complexes were characterized by powder X-ray diffraction (XRD), Fourier transform infrared (FTIR), thermogravimetry (TG), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). Batch experiments were designed to investigate the sorption behavior of pyrene onto the clays in the presence of DOM. The maximum sorption capacities of pyrene on MT, CMT, KL, and CKL were 22.18, 38.96, 42.00, and 44.99 g⋅g −1 , respectively, at the initial concentration of 1000 ± 150 g⋅L −1 . The sorption isotherms of pyrene by the bare clays followed the Henry model well, whereas the Freundlich sorption isotherm provided a better fit to the equilibrium data of the sorption by the complexes. The role of montmorillonite and kaolinite complexes with DOM in the retention of pyrene in soils was different. This may be due to the different crystal structures between montmorillonite and kaolinite.

The oxidation leaching of chromium from electroplating sludge was investigated, and ultrasonication was introduced for the enhancement of the leaching process. Two different types of Cr-bearing electroplating sludge were selected for the study, and the effects of the reagent dosage, temperature, and ultrasonic pulse ratio on the leaching efficiency were tested through oxidation leaching experiments. The experimental results show that hydrogen peroxide and sodium hypochlorite exhibit different leaching effects on different types of electroplating sludge. The control of reagent dosage is crucial for the oxidation leaching of Cr, while the effect of temperature turns out to be small. Hydrogen peroxide turns out to be a more effective oxidizer for chromium sludge, and the leaching efficiency of Cr could be promoted from 77.52% to 87.08% using ultrasonic enhancement under optimum conditions. Interestingly, sodium hypochlorite exhibited better leaching efficiency than hydrogen peroxide for the mixed sludge since the organic matter in the mixed sludge will lead to the rapid decomposition and consumption of hydrogen peroxide. The leaching efficiency of Cr from the mixed sludge could also be promoted from 56.82% to 67.10% using ultrasonic enhancement under optimum conditions. According to the scanning electron microscope imaging, ultrasonic enhancement can create voids and cracks on the surface of the sludge particles, hence promoting the contact between electroplating sludge and leaching agents, and promoting the oxidation leaching efficiency. In addition, ultrasound seems to be able to remove the coverings on the surface of the mixed sludge particles, which may facilitate the oxidation reaction.

Little is known about whether the application of biogas residues in rice fields will affect the degradation of pesticides. This study investigated the dissipation behavior of the fungicide difenoconazole in paddy water and sediment after the application of a chemical fertilizer or biogas residues. The results showed that the application of biogas residues changes the dissipation of difenoconazole in both paddy water and sediment. The half-lives of difenoconazole in paddy water and sediment with biogas residues were 0.50 and 10.09 days, respectively, while the half-lives of difenoconazole in paddy water and sediment with chemical fertilizer were only 0.22 and 4.64 days, respectively. After biogas residues were applied in a paddy field, no significant changes in pH value of paddy water and sediment and soil microorganisms were observed, but soil organic matter decreased by 30%. The above studies suggest that biogas residues may affect the dissipation of pesticides in paddy field water and sediments, which provides a new focus on the scientific and rational use of biogas residues as organic fertilizer in rice fields.

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