H₃PO₄ activated Typha angustifolia and Salix matsudana carbons provide good adsorption/desorption characteristics for Cd and Pb.

The development of novel catalysts for degrading organic contaminants in water is a current hot topic in photocatalysis research for environmental protection. In this study, C₃N₅ nanosheet/Ag₂CO₃ nanocomposites (CNAC-X) were used as efficient photocatalysts for the visible-light-driven degradation of methylene blue (MB), and tetracycline hydrochloride (TC-HCl) was synthesized for the first time using a simple thermal oxidative exfoliation and in situ deposition method. Due to the synergistic effect of nanosheet structures, carbon defects, and Z-scheme heterojunctions, CNAC-10 exhibited the highest photocatalytic activity, with photodegradation efficiencies of 96.5% and 97.6% for MB (60 mg/L) and TC-HCl (50 mg/L) within 90 and 100 min, respectively. The radical trapping experiments showed that ·O₂⁻ and h⁺ played major roles in the photocatalytic effect of the CNAC-10 system. Furthermore, intermediates in the photodegradation of MB and TC-HCl were investigated to determine possible mineralization pathways. The results indicated that C₃N₅ nanosheet/Ag₂CO₃ photocatalysts prepared in this work could provide an effective reference for the treatment of organic wastewater.

In this study, exogenous spermidine role on Salix matsudana tolerance to cadmium was evaluated. Spermidine and cadmium presented antagonistic effects on the biomass, copper and zinc concentrations in S. matsudana. cadmium mainly distributed in the cell wall of subcellular fraction; 46.97%–60.43% of cadmium existed in a sodium chloride-extracted form. Cadmium contents in roots, leaves, and twigs ranged from 2002.67 to 3961.00, 111.59 to 229.72, and 102.56 to 221.27 mg/kg, respectively. Spermidine application elevated cadmium concentrations in the roots, cuttings, and cell wall and the ratio of deionized water-extracted cadmium, but decreased cadmium levels in the twigs and leaves and the fractions of cadmium extracted by ethanol and sodium chloride, respectively. Putrescine and malondialdehyde were important indicators of cadmium-induced oxidative damage. Exogenous spermidine alleviated the accumulation of superoxide anion, hydrogen peroxide, malondialdehyde via promoting the levels of spermidine, soluble protein, superoxide dismutase, reductive ascorbate, glutathione reductase, and glutathione peroxidase in S. matsudana leaves under the corresponding cadmium stress. The results indicated that S. matsudana was a candidate for cadmium rhizoremediation and extraction in leaves; the spermidine application enhanced the cadmium tolerance of S. matsudana through promoting cadmium accumulation in roots, cell wall, and less bioactive chemical forms and the antioxidative ability.

In this study, Box–Behnken design (BBD) was employed to optimize the process for H₃PO₄-activated Typha angustifolia activated carbon (TAC) production and Cr removal by TAC; the removal mechanisms were discussed based on TAC characterization, and the regeneration evaluation was also conducted. The optimum preparation conditions were activated time of 1.5 h, temperature of 469.02 °C, and incubation ratio of 4, resulting in an experimental carbon yield of 38.23% and Cr removal of 90.01%. The optimum adsorption parameters were found to be 0.02 g/50 mL TAC, 80 mg/L Cr(VI), and 2.21 pH with the observed Cr adsorption capacity of 59.54 mg/g. The removal mechanisms involved coulombic attraction, ionic exchange, surface complexation, and reduction. The process of Cr(VI) adsorption was feasible, spontaneous, and endothermic in nature, and the pseudo-second-order and Langmuir isotherm models were more appropriate for the removal process. After five adsorption/desorption cycles, the Cr adsorption capacity on TAC reduced by only 24.37%. The results showed that BBD could successfully optimize TAC production and Cr removal, and TAC could be developed as a promising, eco-friendly, and effective adsorbent for Cr pollution control.