磺酸基改性磁性吸附剂去除水中的Cu(Ⅱ)

Removal of Cu(Ⅱ) by sulfonic acid modified magnetic adsorbent

利用水热法制备出Fe3O4磁性粒子,通过正硅酸乙酯水解使Fe3O4外面包覆SiO2(Fe3O4@SiO2),最后利用3-氨丙基三甲氧基硅烷和氯磺酸进行改性,合成了磺酸基改性磁性吸附剂.采用FT-IR、BET和XRD等方法对合成吸附剂进行表征,并探讨接触时间、初始浓度、溶液pH值等因素对吸附性能的影响.表征结果显示,成功合成了磺酸基改性磁性Fe3O4@SiO2粒子;Fe3O4@SO3Na比表面积为20.4587m^-2·g^-1.吸附实验结果显示,在25℃条件下,Fe3O4@SO3Na对Cu^2+的吸附等温线符合Freundlich吸附等温方程,实验条件下最大吸附量为16.13mg·g^-1.Fe3O4@SO3Na吸附Cu^2+可在1h内达到吸附平衡且吸附动力学遵循拟二级动力学模型.溶液中存在盐离子时,发现盐离子的存在对吸附效果几乎没有影响;溶液中含有柠檬酸时对吸附效果产生抑制.吸附剂经3次循环使用后仍有吸附性能,表明吸附剂具有良好的再生性和经济性.

The Fe3O4 magnetic particles were prepared by hydrothermal method,and its surface coating of SiO2 was by hydrolysis of ethyl orthosilicate.Finally,the sulfonic acid group-modified magnetic adsorbent was synthesized by modification of Fe3O4@SiO2 with 3-aminopropyltrimethoxysilane and chlorosulfonic acid.The magnetic adsorbent was characterized by FT-IR,BET and XRD.The effects of contact time,initial concentration,solution pH and other factors on the adsorption performance were investigated.The characterization results showed that the sulfonic acid-modified magnetic Fe3O4@SiO2 particles were successfully synthesized and the specific surface area of Fe3O4@SO3Na is 20.4587 m^-2·g^-1.The adsorption experiment results depicted that the Cu^2+ adsorption Fe3O4@SO3Na was well fitted by Freundlich adsorption isotherm model.The maximum adsorption capacity under experimental conditions was 16.13 mg·g^-1.Adsorption of Cu^2+ reached adsorption equilibrium within 1 h and the adsorption kinetics followed a pseudo-second-order kinetic model.When salt ions were present in the solution,it was found that the presence of salt ions had no effect on the adsorption effect.Adsorption of Cu^2+ on the adsorbent was inhibited in presence of citric acid.The adsorbent still had good adsorption performance after 3 regenerations which shows recyclability of the system to reduce associated cost.