石墨烯凝胶电极的制备及电吸附Pb2+的性能

电吸附去除水中重金属离子具有吸附容量高和电极可再生的优点.本文采用高温水热法还原氧化石墨烯(GO)得到石墨烯水凝胶(GS)并经压片制得GS电极.本文对GS电极的电化学性能进行了测试,考察了GS电极电吸附Pb~(2+)的动力学和热力学特性,以及电极的脱附和循环使用情况.结果表明,GS电极的电化学性能优异,其单位质量比电容高达200.4 F·g~(-1)(1 A·g~(-1));提高电压有利于GS电极电吸附Pb~(2+),电压为-1.2 V时,GS电极对Pb~(2+)的去除率达96.4%;GS电极电吸附Pb~(2+)的饱和吸附量达461.20 mg·g~(-1),是不加电时饱和吸附量的2倍;施加反向电压可以实现Pb~(2+)的脱附和电极再生,电吸附-脱附15次后,电极对Pb~(2+)的去除率保持在95%以上.

Preparation and Pb2+ Electrosorption Characteristics of Graphene Hydrogels Electrode

Electrosorption has the advantage of high adsorption capacity and electrode regeneration in the removal of heavy metal ions in water. In this study, graphene hydrogels (GS) were prepared by hydrothermal reduction of graphene oxide (GO) suspensions and the electrode was obtained via compression of GS. Various electrochemical properties of GS were tested. The kinetics and thermodynamics of the electrosorption of Pb²⁺ on GS electrode and GS electrode reusability were investigated. The results showed excellent capacitive behavior (200.4 F·g^-1 at 1 A·g^-1) of GS. The electrosorption performance of GS indicated that high voltage was favored for the removal of Pb²⁺ and the highest removal efficiency reached 96.4% when the voltage value was -1.2 V. The electrosorption capacity for Pb²⁺ removal was found to be 461.20 mg·g^-1, which was twice as high as the saturated adsorption capacity of GS. The GS electrode could regenerate after electrosorption when the voltage value was+1.2 V and the removal efficiency of Pb²⁺ was still maintained above 95% after electrosorption-desorption for 15 cycles.