It is often difficult for the modification of impermeable bentonite to meet the requirements of low permeability, high chemical resistance, and strong adsorption performance. Based on the low permeability and high chemical resistance of the modified bentonite with sodium polyacrylate (SPB), the adsorption characteristics of the modified bentonite on copper were further compared and analyzed. A series of batch adsorption experiments were performed considering the effects of contact time, pH, temperature, and adsorbate concentration. The morphological changes and microstructure of raw bentonite and SPB at different cupric ion (Cu2+) concentrations were studied through scanning electron microscopy. The pore structure was analyzed with mercury intrusion porosimetry. Kinetic, Langmuir, and Freundlich models were applied to analyze the adsorption mechanism. The results indicated that the SPB not only improves the impermeability and chemical resistance of bentonite but also significantly improves the adsorption of heavy metals. The saturated adsorption capacity of Cu2+ is increased by 116.08 %. The modification mechanism of SPB is that the mineral particles of bentonite were coated by a negatively charged and hydrophilic group (carboxyl group, -COO-). The protective effect of the polymer on the bentonite is the main reason for its chemical resistance, and the solid bonding of the polymer closes the pores of the material, thus reducing the hydraulic performance. Based on the above, it can be concluded that SPB has the characteristics of lower permeability, stronger chemical corrosion resistance, and greater heavy metal adsorption capacity, which makes it an ideal anti-seepage material for landfill.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.