ZHANG Dan1, Zhang Shirong1, WANG Xinyue1, WANG Guiyin1, GUO Xin2, Feng Can1
（1.College of Environmental Sciences, Sichuan Agricultural University, Chengdu 611130, China;
2. Chengdu Academy of Environmental Sciences, Chengdu 610072, China）
Abstract：In order to solve the problem of wastewater treatment with respect to heavy metals and find high-efficiency and low-cost biosorbent, four materials derived from the stems of Dendranthema indicum (DI), Artemisia argyi (AA), and Mentha haplocalyx (MH), and the peel of Citrus limon (CL), were selected to study the adsorption of lead ions in water. SEM, BET, and FTIR were used to characterize the materials, and the effects of absorbent dosage, initial pH and coexisting cations on the adsorption quantity were discussed. The lead adsorption capacities of four materials in simulated wastewater decreased logarithmically with increasing dosages (P<0.05), and increased firstly and then stabilized gradually with increasing solution pH. Pseudo first order kinetic described the dynamic adsorption process of Pb2+ by the stem of Dendranthema indicum more suitable than other models, while pseudo second order kinetic described such process more better for the stems of Artemisia argyi and Mentha haplocalyx, and the peel of Citrus limon. The adsorption of Pb2+ by the stems of Dendranthema indicum and Artemisia argyi is a single-layer adsorption mainly based on chemical adsorption, which follows by the Langmuir model. The adsorption of Pb2+ by the stem of Mentha haplocalyx and the peel of Citrus limon, is mainly irregular multi-molecular layer adsorption, that suitable with the Freundlich model. Coexisting cations, including Mg2+, Cu2+, and Al3+, generated competitive adsorption with Pb2+ in the adsorption process, thus significantly reduced the adsorption amount of Pb2+ on the materials (P<0.05). The adsorption capacity of the four plant materials is MH > AA > CL >DI. Therefore, four plant materials have the potential for adsorbing lead ions in wastewater.
Key words：plant material; lead adsorption; competitive adsorption; coexisting cation
EARTH AND ENVIRONMENT Vol.48, No.6, Tot No.338, 2020, Page 711-718
