改性石墨烯电吸附去除水中砷离子

Study on Electrosorption of As Ions in Aqueous Solution by Modified Graphene

采用水热法制备得到改性石墨烯材料:石墨烯/TiO2(GA/TiO2)复合材料。通过扫描电镜(SEM)、透射电镜(TEM)、氮气吸附-脱附、拉曼光谱、电化学等手段对石墨烯(GA)和GA/TiO2材料的外观形貌、孔隙结构、电化学性能等进行了表征;将GA和GA/TiO2材料组装成电极,应用于电容去离子(CDI)去除砷离子,分析电压、循环流速、温度和初始浓度对砷离子去除效果的影响。结果表明:GA/TiO2材料具有三维孔状结构,比表面积为416.99m^2·g^-1,比电容为320.75F·g^-1,优于GA材料。GA/TiO2电极CDI除砷性能优于GA电极。随着电压的升高,砷离子去除率和吸附量均增大;随着温度的升高,砷离子去除率和吸附量均减少;随着初始离子质量浓度的增大,砷离子吸附量增加,去除率减小;而循环流速对砷离子去除率没有明显影响。GA/TiO2电极对砷离子吸附过程符合准一级动力学模型和Freundlich等温模型。

In this paper,the modified graphene material,graphene/titanium dioxide(GA/TiO2)composite,was prepared by hydrothermal method.The morphology,pore structure and electrochemical properties of graphene(GA)and GA/TiO2 were characterized by scanning electron microscopy(SEM),transmission electron microscopy(TEM),nitrogen adsorption-desorption,Raman spectroscopy and electrochemistry.Then GA and GA/TiO2 were assembled into electrodes to remove As ions by capacitive deionization(CDI)method.The removal efficiency of As ions was analyzed through different experimental conditions including voltage,circulating flow rate,temperature and initial As ion concentration.The results show that GA/TiO2 had a three-dimensional porous structure with specific surface area of 416.99 m^2·g^-1 and specific capacitance of 320.75 F·g^-1,which were better than that of GA.In addition,the removal performance of As ions by CDI on GA/TiO2 electrode was better than that of GA electrode.The removal efficiency and adsorption capacity of As ions increased with the increase in voltage,but decreased with the increase in temperature.However,the removal efficiency decreased and adsorption capacity increased with the increase in initial ion concentration.The circulating flow rate had no significant effect on the removal efficiency.Moreover,the adsorption process of As ions on GA/TiO2 electrode can be well fitted by the pseudo-first order kinetic model and Freundlich model.