The pseudocapacitive Na ion storage behaviour of WS₂ nanosheets was systematically investigated by various ex/in situ experimental analyses and theoretical calculations.

The excessive application of phosphate fertilizers easily causes water eutrophication. Phosphorus recovery by adsorption is regarded as an effective and simple intervention to control water bodies’ eutrophication. In this work, a series of new adsorbents, layered double hydroxides (LDHs)-modified biochar (BC) with different molar ratios of Mg²⁺ and Fe³⁺, were synthesized based on waste jute stalk and used for recycling phosphate from wastewater. The prepared LDHs-BC4 (the molar ratio of Mg/Fe is 4:1) has significantly high adsorption performance, and the recovery rate of phosphate is about 10 times higher than that of the pristine jute stalk BC. The maximum adsorption capacity of LDHs-BC4 for phosphate was 10.64 mg-P/g. The main mechanism of phosphate adsorption mainly includes electrostatic attraction, ion exchange, ligand exchange, and intragranular diffusion. Moreover, the phosphate-adsorbed LDHs-BC4 could promote mung bean growth, which indicated the recovery phosphate from wastewater could be used as a fertilizer.

Biochar loading mixed–phase iron oxide shows great advantages as a promising catalyst owing to its eco–friendliness and low cost. Here, γ–Fe₂O_3−x@biochar (E/Fe–N–BC) composite was successfully prepared by the sol–gel method combined with low–temperature (280 °C) reduction. The Scanning Electron Microscope (SEM) result indicated that γ–Fe₂O_3−x particles with the size of approximately 200 nm were well–dispersed on the surface of biochar. The CO derived from biomass pyrolysis is the main reducing component for the generation of Fe (II). The high content of Fe (II) contributed to the excellent catalytic performance of E/Fe–N–BC for quinclorac (QNC) degradation in the presence of peroxymonosulfate (PMS). The removal efficiency of 10 mg/L of QNC was 100% within 30 min using 0.3 g/L γ–Fe₂O_3−x@biochar catalyst and 0.8 mM PMS. The radical quenching experiments and electron paramagnetic resonance analysis confirmed that •OH and SO₄•⁻ were the main radicals during the degradation of QNC. The facile and easily mass–production of γ–Fe₂O_3−x@biochar with high catalytic activity make it a promising catalyst to activate PMS for the removal of organic pollutants.

Sulfentrazone is an excellent herbicide for the control of broad-leaved weeds and some grasses. However, its herbicidal residues pose potential risks to the environment. The use of carbonaceous materials as catalysts for activating peroxymonosulfate (PMS) for managing pesticide contamination has attracted considerable attention. Herein, the rapid degradation of sulfentrazone in water and the alleviation of sulfentrazone-induced phytotoxicity alleviation to rice were investigated using glucose-montmorillonite hydrochar (GM-HC) activating PMS. The findings revealed that the GM-HC/PMS system can rapidly degrade sulfamethoxazole and achieved 93.90% of removal efficiency in 24 h. Specifically, GM-HC activating PMS generated the active species, including sulfate radicals (SO₄•^–), singlet oxygens (¹O₂) and superoxide radicals (O₂•⁻), which speeds up the degradation of sulfentrazone. Five major degradation products of sulfentrazone and two possible degradation pathways were proposed. The C-Cl and C-CH₃ of sulfentrazone molecules are the initiation sites attacked by active species for degradation according to density functional theory (DFT) calculation. Additionally, after the sulfentrazone was degraded by GM-HC/PMS system, sulfentrazone-induced phytotoxicity to rice seeds and seedlings was significantly alleviated. This work presents a novel approach for addressing herbicide wastewater pollution. Graphical Abstract