摘要
水环境中砷的深度处理对减少环境污染和确保人类健康至关重要。自制了三维电极反应器,以活性炭颗粒为粒子电极材料,采用电吸附和物理/化学吸附联合模式实现As(Ⅴ)的深度处理。经优化后,As(Ⅴ)浓度可从0.5 mg/L降至0.032 mg/L,且均以H_(2)AsO_(4)-形式存在,无As(Ⅲ),表明不存在氧化还原反应。动力学研究发现,电吸附过程可分为三步:从溶液到电极材料表面的液膜扩散过程、从电极材料表面到内部孔隙的内扩散过程和电吸附接近平衡状态。为验证该工艺的循环性能,开展了电吸附-电脱附工艺研究,发现经过8次循环后,出水浓度仍仅为0.098 mg/L(低于0.1 mg/L的标准限值),实现了含砷废水的高效深度处理,但去除效率需提升、吸附后材料的处理仍需改进。
Deep treatment,a method for further reducing the content of a target substance,for toxic arsenic(As)from water is vital to reduce environmental pollution and ensure human health.Here,we employed electrosorption of As(V)from water in a self-made three-dimensional reactor with granular activated carbon(GAC).The As(V)concentration can be decreased from 0.5 to 0.032 mg/L under optimal conditions,and all of the As practically presented as H_(2)AsO_(4)−without As(III),indicating that there was no redox reaction.After kinetic studies and comparisons of pseudo-second-order kinetic,intra-particle diffusion and Boyd models,the electrosorption could be divided into three steps:internal diffusion from the surface of materials to internal pores,liquid film diffusion from the solution to the surface of materials,and the closure of the entire adsorption process to the equilibrium state.In order to verify the cyclic performance of this process,electrosorption-electrodesorption process research was carried out,and it was found that after 8 cycles,the concentration in the effluent was still only 0.098 mg/L,which was lower than the limitation.Above all,both removal efficiency and disposal of adsorption materials should be ameliorated even though As(V)could be removed in depth and recycled.
作者
罗永健
王云燕
何紫彤
许欢
孙竹梅
LUO Yong-jian;WANG Yun-yan;HE Zi-tong;XU Huan;SUN Zhu-mei(School of Metallurgy and Environment,Central South University,Changsha 410083,China;Chinese National Engineering Research Center for Control&Treatment of Heavy Metal Pollution,Changsha 410083,China;School of Environment and Safety Engineering,North University of China,Taiyuan 030051,China)
基金
Project(2021M703651)supported by the Postdoctoral Science Foundation of China
Project(52121004)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of China
Project(51825403)supported by the National Natural Science Fundation for Distinguished Young Scholars of China
Project(2021RC2010)supported by the Science and Technology Innovation Program of Hunan Province,China。
关键词
电吸附
砷
活性炭颗粒
三维电极反应器
砷的去除
electrosorption
arsenic
granular activated carbon
three-dimensional electrode reactor
arsenic removal
