氨基化纤维基生物质吸附剂吸附铜离子的机理OA

To develop a low-cost and renewable fiber-based biomass adsorbent for efficient removal of copper from wastewater,alligator weed(Alternanthera philoxeroides)was used as the biomass substrate and graft-modified with epichlorohydrin and diethylenetriamine in an N,N-dimethylformamide medium.An aminated network-crosslinked fiber-based adsorbent,namely modified Alternanthera philoxeroides(MAP),was thereby prepared.The material structure and surface properties were comprehensively characterized using morphology observation,functional-group identification,crystal structure analysis,and surface chemical-state analysis.The adsorption behavior of MAP toward Cu2+in water was systematically investigated,focusing on the effects of adsorbent dosage,contact time,solution pH,initial concentration,and temperature.The results showed that the modified material exhibited a rough and porous surface compared with the relatively smooth pristine biomass.Under the conditions of an initial Cu2+concentration of 100 mg/L,MAP dosage of 5 g/L,pH 5.5,temperature of 298 K,and contact time of 180 min,the equilibrium adsorption capacity and removal efficiency reached 19.33 mg/g and 95.57%,respectively.Kinetic and isotherm analyses indicated that the adsorption process followed the pseudo-second-order model and the Langmuir isotherm model,with a maximum Langmuir monolayer adsorption capacity of 58.56 mg/g at 298 K.Thermodynamic parameters(ΔG<0 and ΔH>0)revealed that the adsorption was spontaneous and endothermic.Combined analysis of adsorption behavior and changes in surface functional groups and chemical states indicated that Cu2+removal was mainly attributed to amino-group coordination complexation.Regeneration experiments demonstrated good reusability of the adsorbent,with the removal efficiency remaining≥72.06%after six adsorption-desorption cycles.This study provides a promising low-cost and renewable fiber-based biomass adsorbent option for the treatment of copper-containing wastewater.