纳米零价铁铜双金属对铬污染土壤中Cr(Ⅵ)的还原动力学  

Reduction Kinetics of Cr(Ⅵ) in Chromium Contaminated Soil by Nanoscale Zerovalent Iron-copper Bimetallic

作　　者：马少云[1] 祝方[1] 商执峰 

机构地区：[1]太原理工大学环境科学与工程学院,太原030024

出　　处：《环境科学》2016年第5期1953-1959,共7页Environmental Science

基　　金：国家自然科学基金项目(21276174);山西省基础研究计划项目(2013011040-1)

摘　　要：采用液相还原法制备纳米零价铁铜双金属(n ZVI/Cu),通过扫描电子显微镜(SEM)和X射线衍射(XRD)对其进行形貌观测和表征分析,用制备的n ZVI/Cu修复Cr(Ⅵ)污染的土壤,研究了不同反应条件对修复效果的影响,探讨了还原动力学规律.结果表明,n ZVI/Cu对土壤中的Cr(Ⅵ)有很好的降解效果,反应初始p H为7,温度为30℃时,加入2 g·L^(-1)的n ZVI/Cu材料,在10 min内Cr(Ⅵ)含量为88 mg·kg^(-1)的污染土壤中的Cr(Ⅵ)去除率可以达到99%以上.改变n ZVI/Cu加入量、p H值、反应温度以及添加腐殖酸都会对Cr(Ⅵ)的去除效果产生影响.改变p H值和反应温度对去除土壤中Cr(Ⅵ)的影响都比较明显,p H值越小,反应温度越高Cr(Ⅵ)的去除效果越好,添加腐殖酸对去除土壤中的Cr(Ⅵ)有一定的影响.n ZVI/Cu降解Cr(Ⅵ)的过程符合伪一级还原动力学模型,还原速率与反应温度的关系符合阿仑尼乌斯(Arrhenius)定律,反应活化能Ea为104.26 k J·mol^(-1).Nanoscale zerovalent iron-copper bimetallic （nZVI/Cu） was produced by liquid-phase reduction and characterized by SEM and XRD. The remediation of Cr （Ⅵ ） contaminated soil was conducted with nZVI/Cu, and the affecting factors and reduction kinetics were investigated. The results indicated that nZVI/Cu was effective in the degradation of Cr（ Ⅵ ） in soil at an initial pH of 7 at 30℃. After 10 min of reaction, Cr（Ⅵ） in the soil was completely degraded when the concentration of nZVI/Cu was 2 g·L^-1 and the concentration of Cr（Ⅵ） in contaminated soil was 88 mg·kg^-1. nZVI/Cu amount, pH value, reaction temperature, and the concentration of humic acid affected the degradation of Cr（ Ⅵ ）. The removal efficiency of Cr（ Ⅵ ） increased with increasing reaction temperature and decreased with increasing initial pH value. Humic acid had a certain impact on the degradation of Cr（ Ⅵ ） in soil. The removal of Cr （ Ⅵ ） followed the pseudo first order reduction kinetics model, and the relationship between the reduction rate and the reaction temperature accorded with Arrhenius law, and the reaction activation energy （Ea） was 104.26 kJ·mol^-1.

关 键 词：nZVI/Cu 土壤修复 CR(VI) 还原动力学 降解机制 

分 类 号：X131.3[环境科学与工程—环境科学] X53