以海藻酸钠(SA)作为基体材料,采用离子交联法包埋纳米颗粒(Fe3O4)与不同类型的粘土矿物制备磁性复合凝胶,研究其对铊(Tl)的吸附性能.通过实验探究并对比了不同粘土矿物形成的磁性 SA 凝胶在不同凝胶投加量、pH 条件下对 Tl(Ⅰ)吸附效果的影响.结果表明,SA@Fe3O4/伊利石凝胶吸附效果优于SA@Fe3O4/高岭土凝胶,而在条件为pH=5、投加量为 1.5 g时复合凝胶获得较好的吸附效率,去除率达到 82％,远高于未添加粘土矿物的 SA@Fe3O4 材料(21.38％).经吸附动力学研究表明,复合凝胶吸附过程更符合Freundich方程和准二级动力学方程,从红外光谱、XPS和XDR分析结果可以看出,材料对Tl(Ⅰ)的吸附存在离子交换过程,SA@Fe3O4/伊利石凝胶中的含氧官能团在反应中对Tl(Ⅰ)起配位作用.SA@Fe3O4/伊利石凝胶可作为Tl(Ⅰ)吸附材料应用于地下水铊污染原位修复.
Adsorption Properties of Tl(Ⅰ)on Clay Minerals Based Magnetic Sodium Alginate Gel
Using sodium alginate(SA)as a matrix material,magnetic composite gel was prepared by ion crosslinking method to entrap nanoparticles(Fe3O4)and different types of clay minerals,and its adsorption performance for thallium(Tl)was studied.The influence of magnetic SA gel formed by different clay minerals on Tl(Ⅰ)adsorption under different gel dosage and pH conditions was explored and compared through experiments.The results indicate that the adsorption effect of SA@Fe3O4/illite gel is better than SA@Fe3O4/Kaolin gel.In contrast,when pH=5 and dosage is 1.5 g,the composite gel has a better adsorption efficiency.The removal rate reaches 82％,much higher than the composite gel without clay minerals SA@Fe3O4 Material(21.38％).The adsorption kinetics study shows that the adsorption process of composite gel is more consistent with the Freundich and quasi-second-order kinetics equations.From the results of infrared spectroscopy,XPS,and XDR analysis,it can be seen that the adsorption of Tl(Ⅰ)by the material involves an ion exchange process,SA@Fe3O4/The oxygen-containing functional group in illite gel plays a coordination role to Tl(Ⅰ)in the reaction.SA@Fe3O4/illite gel can be used as Tl(Ⅰ)adsorption material for in-situ remediation of groundwater thallium pollution.
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