纳米铁对地下水中As(Ⅲ)的吸附动力学  

Adsorption Kinetics of As(Ⅲ) from Groundwater by Nanoscale Zero-Valent Iron

作　　者：黄园英[1] 刘丹丹[2] 李桂荣[3] 

机构地区：[1]国家地质实验测试中心,北京100037 [2]中国地质大学水资源与环境学院,北京10008 [3]郑州大学水利与环境学院,河南郑州450001

出　　处：《地球科学（中国地质大学学报）》2012年第2期294-300,共7页Earth Science-Journal of China University of Geosciences

基　　金：水体污染控制与治理科技重大专项(No.2009ZX07424-002);污染土壤和水体的环境控制与地球化学修复技术(No.1212011120286);国家地质实验测试中心基本科研业务费项目(No.201012CSJ02)

摘　　要：实验室合成制得的纳米铁BET比表面积为49.16m2/g,直径范围为20～40nm.通过批实验考察纳米铁对As(Ⅲ)吸附动力学情况.结果表明,在20℃、pH为7时,纳米铁能够快速地去除As(Ⅲ),在60min内,0.1g纳米铁对起始浓度为910μg/L溶液As(Ⅲ)去除率大于99%.反应遵循准一级反应动力学方程,标准化后的As(Ⅲ)速率常数kSA为2.6mL/(m2·min).纳米铁对As(Ⅲ)的吸附等温曲线能够很好地满足Langmuir和Freundlich方程,相关系数R2>0.95,由Langmuir模型获得单层纳米铁的最大吸附量为76.3mg/g.0.1mol/LNaOH对吸附在纳米零价铁(NZVI)的As(Ⅲ)解吸率为21%.在竞争阴离子中,SiO32-和H2PO4-对As(Ⅲ)的去除有明显阻碍作用,而其他离子基本上没有影响.纳米铁对As(Ⅲ)的去除机理主要是吸附和共沉淀.Artificial synthesized nanoscale zero-valent iron（NZVI） was used in the laboratory for the removal of As（Ⅲ）.The average BET surface area of particles was 49.16 m2/g,with a diameter in the range of 20-40 nm.Batch experiments were carried out to study the efficiency of inorganic arsenic removal and adsorption kinetics by NZVI.The results show that As（Ⅲ） can be removed efficiently by NZVI at pH 7,20 ℃.The removal rate for As（Ⅲ） is over 99% within 60 minutes by reacting 910 μg/L As（Ⅲ） with 0.1 g NZVI.The As（Ⅲ） adsorption process follows the pseudo-first-order kinetic expression.The surface-area-normalized rate coefficient kSA is 2.6 mL·m-2·min-1 for As（Ⅲ）.The equilibrium adsorption data fit Langmuir and Freundlich adsorption model well,with values of the constants at the regression coefficient（R2〉0.95） for both models.The monolayer adsorption capacity of the sorbent,as obtained from the Langmuir isotherm,76.3 mg/g is of NZVI.21% As（Ⅲ） adsorpted on NZVI was found to desorption by sodium hydroxide solution（0.1 M）.The effect of competing anions shows SiO32-and H2PO4-markedly decrease with the removal of As（Ⅲ）,while the effect of other anions is insignificant.The mechanism of As removal is adsorption and coprecipitation.

关 键 词：纳米铁 As(Ⅲ) 吸附动力学 解吸 去除率 地下水 污染控制 环境工程 

分 类 号：X523[环境科学与工程—环境工程]