Preparation of Nitrosulfonated Humic Acid-based Ion-imprinted Polymer and Study on Its Adsorption Properties

Ion imprinted polymer, a kind of high molecular organic polymer, which can separate and enrich various metal ions in water by changing the adsorption conditions. Used humic acid as raw materials, used HNO 3 and H 2 SO 4 as modifiers to synthesize nitrosulfonated humic acid, then used it as substrate, NIPAM as the functional monomer, Pb 2+ as the template ion, MBA as the crosslinking agent, K 2 S 2 O 8 and NaHSO 3 as initiators to prepare lead ion imprinted polymers after cross-linking reaction. Used SEM, FT-IR, TG-DSC to characterize the obtained product, and explored the structure and performance of the product. The adsorption performance of IIPs (NSA/NIPAM) was studied by ultraviolet-visible spectrophotometry (UV-vis). The results show that the maximum adsorption capacity of IIPs (NSA/NIPAM) for Pb 2+ is 81.33 mg/g, the optimal number of cycles of IIPs (NSA/NIPAM) is 10, In the presence of competing ions Cu 2+ and Cd 2+ , selectivity coefficients are 18.04 (Pb 2+ /Cu 2+ ) and 19.39 (Pb 2+ /Cd 2+ ). The results of simulating the thermodynamic adsorption process of the polymers with Langmuir and Freundlich thermodynamic adsorption models show that the imprinted polymer conform to the second-order kinetic model and the Langmuir thermodynamic model, and belong to monolayer chemisorption.