摘要
纳米零价铁(nZVI)存在易团聚、钝化和迁移性差等问题,影响对六价铬[Cr(Ⅵ)]污染地下水的原位修复效果。为了开发一种低成本、绿色的nZVI改性材料,以球磨生物炭(BC)为载体负载nZVI,构建了nZVI@BC反应体系,再利用羧甲基纤维素(CMC)稳定nZVI@BC,合成了一种新型高效、抗钝化纳米级别的修复材料CMC-nZVI@BC。对改性前后的nZVI进行表征分析,探究了材料添加量、Cr(Ⅵ)初始质量浓度、初始pH值、温度及地下水化学组分对CMC-nZVI@BC去除Cr(Ⅵ)的影响,并阐明去除Cr(Ⅵ)的机理。得出如下结论:(1)铁碳质量比为2∶1时的nZVI@BC对Cr(Ⅵ)的去除效果最好,3 h内0.6 g/L CMC-nZVI@BC对50 mg/L Cr(Ⅵ)的去除率达99.9%,表现出较高的去除Cr(Ⅵ)的速率和能力;(2)去除Cr(Ⅵ)的主要机制是通过还原和沉淀反应;(3)在pH值2~10范围内,pH值对去除Cr(Ⅵ)有显著影响,温度影响较小;(4)SO_(2-)_(4)的存在促进了Cr(Ⅵ)的去除,而HCO^(-)_(3)、 NO^(-)_(3)、Ca^(2+)、Mg^(2+)和腐殖酸对Cr(Ⅵ)的去除均有不同程度的抑制作用。这些结果表明,CMC-nZVI@BC可以作为有效去除Cr(Ⅵ)的原位修复药剂,为nZVI在地下水原位修复的应用提供了依据。
Nano zero-valent iron(nZVI)has problems such as agglomeration,passivation and poor transportability,which affect the in situ remediation effect of Cr(VI)contaminated groundwater.To develop a low-cost,green nZVI modified material,a low-cost,green modification for nZVI was developed.The nZVI@BC reaction system was constructed by supporting nZVI with ball-milled biochar(BC)as carrier and then stabilized with carboxymethyl cellulose(CMC).CMC-nZVI@BC was synthesized as a novel high-efficiency,anti-passivation nano-scale remediation material.The nZVI before and after modification was characterized and analyzed,and the effects of CMC-nZVI@BC addition,initial concentration of Cr(VI),pH and temperature and chemical fraction of groundwater on the removal of Cr(VI)by CMC-nZVI@BC were investigated,and the mechanism of Cr(VI)removal by CMC-nZVI@BC was elucidated,and the following conclusions were obtained:(1)The best removal of Cr(VI)by nZVI@BC at the Fe and C mass ratio of 2∶1;the removal rate of 50 mg/L Cr(VI)by 0.6 g/L CMC-nZVI@BC within 3 h reached 99.9%,exhibiting a high removal rate and capacity of Cr(VI).(2)The main mechanism of Cr(VI)removal by CMC-nZVI@BC was reduction and precipitation.(3)In the range of 2 to 10,the pH value had a significant effect on the removal of Cr(VI)by CMC-nZVI@BC,with less effect of SO_(2)-4 HCO-3 NO-3temperature.(4)The presence of promoted Cr(VI)removal,while,,Ca^(2+),Mg2+and humic acid,all had different degrees of inhibition on Cr(VI)removal.These results suggest that CMC-nZVI@BC can be an effective in situ remediation agent for Cr(VI)removal,offering the possibility of applying nZVI for in situ groundwater remediation.
作者
乔华艺
赵勇胜
胡晶
QIAO Huayi;ZHAO Yongsheng;HU Jing(College of New Energy and Environment,Jilin University,Changchun,Jilin 130021,China;National Local Joint Engineering Laboratory of Petrochemical Pollution Site Control and Remediationn Technology,Jilin University,Changchun,Jilin 130021,China)
出处
《水文地质工程地质》
CSCD
北大核心
2024年第1期190-200,共11页
Hydrogeology & Engineering Geology
基金
国家自然科学基金项目(42072270)。
关键词
地下水修复
纳米零价铁
生物炭
羧甲基纤维素
六价铬
groundwater remediation
nano zero-valent iron
biochar
carboxymethyl cellulose
Cr(VI)
