关键词: 腐植酸, 二氧化硅, 酸化共沉淀, 吸附, 重金属离子

Abstract: Humic acid resin/silica composite was prepared using acidizing and co-precipitating method, with humic acid and water glass as raw materials. The material samples were characterized by means of thermogravimetry, BET specific surface area measurement, Fourier transformation infrared spectroscopy and scanning electron microscope. Adsorption of Cd(II), Cu(II), Ni(II) and Pb(II) was studied in batch tests, and adsorption isotherms were determined in order to evaluate the adsorbing ability of the materials. The results revealed that the specific surface area of the composite material increased with the doping of silicon dioxide, and the stability of composite material in water was improved. Its adsorption mechanisms mainly included ion exchange and complexation or chelation. Langmuir and Freundlich models were applied to examine the data. The experimental results showed that the saturated adsorption amount of Pb2+ on humic acid resin/silica composite material was 262.5 mg/g, that of Cd2+ 43.55 mg/g, that of Ni2+ 23.58 mg/g, and that of Cu2+ 45.54 mg/g. The equilibrium adsorption was found to fit the Langmuir adsorption isotherm.

Key words: humic acid, silica, acidizing and co-precipitation, adsorption, heavy metal ion