电场辅助α-磷酸锆/氧化石墨烯复合材料吸附Sr^(2+)

Electric-field assisted adsorption of Sr^(2+)onα-zirconium phosphate/graphene oxide composites

采用水热法制备了α-磷酸锆(α-ZrP)/氧化石墨烯(GO)纳米复合材料,采用XRD、SEM、EDX、FTIR和XPS对其进行了表征,并将其制成电极,考察了其在电场辅助下对Sr^(2+)的吸附性能。表征结果显示,纳米片状的α-ZrP在具有大比表面积的GO表面生长,团聚现象减少。实验结果表明:在α-ZrP与GO质量比9∶1、外加电压1.2 V、溶液pH 7.0的条件下,采用α-ZrP/GO吸附50 mg/L SrCl2溶液120 min,Sr^(2+)吸附量可达45.28 mg/g,高于纯α-ZrP和GO,约为无电场吸附时的2倍;α-ZrP/GO具有良好的稳定性,可循环使用,5次循环后的Sr^(2+)吸附量仍保持原吸附量的88%;α-ZrP/GO对Sr^(2+)的吸附符合准二级动力学模型和Langmuir等温吸附模型,吸附过程以离子交换反应的化学吸附为主,存在单层吸附。

α-Zirconium phosphate(α-ZrP)/graphene oxide nanocomposites(GO)were prepared by hydrothermal method and characterized by XRD,SEM,EDX,FTIR and XPS.The adsorption capability of the electrode made ofα-ZrP/GO on Sr^(2+)was investigated under electric-field assistance.The characterization results show that nanoflakeα-ZrP grows on the surface of GO with large specific surface area,and the agglomeration phenomenon is reduced.The experimental results show that:Under the conditions of mass ratio ofα-ZrP to GO 9∶1,applied voltage 1.2 V,solution pH 7.0,SrCl2 mass concentration 50 mg/L and adsorption time 120 min,the Sr^(2+)adsorption amount is up to 45.28 mg/g,which is higher than that of pureα-ZrP and GO,and is about two times as much as that without electric field;α-ZrP/GO has good stability and recyclability,and the Sr^(2+)adsorption amount remains 88%of the original adsorption amount after 5 cycles;The adsorption of Sr^(2+)onα-ZrP/GO conforms to the quasi-second-order kinetic model and Langmuir isothermal adsorption model,and the adsorption process is dominated by chemisorption of ion exchange reaction,existing a single layer adsorption.