腐植酸树脂／二氧化硅复合材料制备及其对重金属离子的吸附性能

Preparation of Humic Acid Resin/Silica Composite Material and Its Adsorption Ability to Heavy Metal Ions

以腐植酸和水玻璃为原料,采用酸化共沉淀方法制备了腐植酸树脂/SiO2复合材料.在腐植酸树脂中引入SiO2无机网络后,比表面积有较大提高,在水溶液中的稳定性明显改善.通过差热分析、傅立叶红外光谱、扫描电镜、比表面积测定等方法对样品进行了表征,研究了复合材料对Pb2+,Cd2+,Ni2+,Cu2+四种典型重金属离子的吸附性能,同时探讨了腐植酸组分对重金属离子的吸附机理.结果表明,复合材料中的腐植酸组分对重金属离子的主要吸附形式应为离子交换吸附和络合(或螯合)吸附,复合材料对4种重金属离子有良好的吸附能力,对Pb2+,Cd2+,Ni2+,Cu2+的饱和吸附量分别为262.5,43.55,23.58,45.54mg/g,与同类吸附材料相比处于领先水平,对4种重金属离子的等温吸附符合Langmuir模型.

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 Pb^2＋ on humic acid resin/silica composite material was 262.5 mg/g, that of Cd^2＋ 43.55 mg/g, that of Ni^2＋ 23.58 mg/g, and that of Cu^2＋ 45.54 mg/g. The equilibrium adsorption was found to fit the Langmuir adsorption isotherm.