Simultaneous removal and oxidation of arsenic from water byδ-MnO 2 modified activated carbon  

作　　者：Yulong Wang Hupeng Liu Shaofeng Wang Xuhui Li Xin Wang Yongfeng Jia 

机构地区：[1]Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions,College of Environment and Planning,Henan University,Kaifeng 475004,China [2]Key Laboratory of Pollution Ecology and Environmental Engineering,Institute of Applied Ecology,Chinese Academy of Sciences,Shenyang 110016,China [3]National Demonstration Center for Environmental and Planning,Henan University,Kaifeng 475004,China

出　　处：《Journal of Environmental Sciences》2020年第8期147-160,共14页环境科学学报（英文版）

基　　金：This work was supported by the National Natural Science Foundation of China(Nos.41530643 and 41807358);the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDB14020203);the Joint Fund of NSFC and Henan(No.U1804110).

摘　　要：The ubiquitous arsenic in groundwater poses a great risk to human health due to its environmental toxicity and carcinogenicity.In the present work,a new adsorbent,δ-MnO2 modified activated carbon,was prepared,and its performance for the uptake of arsenate and arsenite species from aqueous solutions was investigated by batch experiments.Various techniques,including FESEM-EDX,p-XRD,XPS and BET surface area analysis,were employed to characterize the properties of the adsorbent and the arsenic adsorption mechanisms.The results showed thatδ-MnO2 covered on the surface and padded in the pores of the activated carbon.Adsorption kinetic studies revealed that approximately 90.1%and 76.8%of As(Ⅲ)and As(V),respectively,were removed by the adsorbent in the first 9 hr,and adsorption achieved equilibrium within 48 hr.The maximum adsorption capacities of As(V)and As(Ⅲ)at pH 4.0 calculated from Langmuir adsorption isotherms were 13.30 and 12.56 mg/g,respectively.The effect of pH on As(Ⅴ)and As(Ⅲ)removal was similar,and the removal efficiency significantly reduced with the increase of solution pH.Arsenite oxidation and adsorption kinetics showed that the As(Ⅴ)concentration in solution due to As(Ⅲ)oxidation and reductive dissolution of MnO2 increased rapidly during the first 12 min,and then gradually decreased.Based on the XPS analysis,nearly 93.3%of As(Ⅲ)had been oxidized to As(V)on the adsorbent surface and around 38.9%of Mn(Ⅳ)had been reduced to Mn(Ⅱ)after As(Ⅲ)adsorption.This approach provides a possible method for the purification of arsenic-contaminated groundwater.

关 键 词：δ-MnO 2 modified activated carbon ARSENATE ARSENITE ADSORPTION OXIDATION 

分 类 号：X703[环境科学与工程—环境工程]