摘要
采用溶胶-凝胶法以十六烷基三甲基溴化铵(CTAB)为模板剂,正硅酸乙酯(TEOS)为硅源,制备以纳米零价铁(nZVI)为核,SiO_(2)为壳层的nZVI@SiO_(2)核壳复合材料,通过SEM、TEM、XRD和BET对材料进行表征,并对nZVI@SiO_(2)活化过硫酸盐(PDS)去除氯苯(MCB)性能进行研究.结果表明,nZVI@SiO_(2)-1材料为均匀的核壳结构;比表面积达到了212.67 m^(2)·g^(-1),壳层厚度为7 nm左右,Fe含量达到了38.92%.在MCB初始浓度为20 mg·L^(-1)、温度(20±2)℃、nZVI@SiO_(2)-1投加量为0.5 g·L^(-1)、PDS投加量为3 mmol·L^(-1)条件下MCB去除率为83.81%.低浓度HA和Cl-对nZVI@SiO_(2)-1/PDS体系去除MCB呈促进作用.而HCO_(3)^(-)、NO_(3)-和SO_(4)^(2-)呈抑制作用,抑制作用大小顺序为HCO_(3)^(-)>NO_(3)^(-)≈SO_(4)^(2-);在酸性及中性条件下nZVI@SiO_(2)-1/PDS对MCB具有较好的去除效果,碱性条件下MCB去除效果受到抑制,pH=5时MCB去除率为89.01%,pH=11时去除率仅为38.63%.自由基捕获(EPR)和自由基猝灭结果表明MCB的降解涉及自由基途径和非自由基途径,其中起主要作用的活性物种有SO_(4)^(·-)、·OH和^(1)O_(2);广谱性实验表明该体系对于多种氯代烃(CHCs)均有较好的去除效果,在实际CHCs污染地下水修复工程中具有较好的应用前景.
The core-shell composites of nZVI@SiO_(2),with a core of zero-valent iron nanoparticles(nZVI)and a SiO_(2) shell layer,were prepared using cetyltrimethylammonium bromide(CTAB)as the template agent and ethyl orthosilicate(TEOS)as the silicon source,with a sol-gel method.The structure of nZVI@SiO_(2) was characterized by using SEM,TEM,XRD and BET.The removal efficiency of chlorobenzene(MCB)by nZVI@SiO_(2) activated persulfate(PDS)was investigated.The results showed that the nZVI@SiO_(2)-1 had a homogeneous core-shell structure,with a specific surface area of 212.67 m^(2)·g^(-1) and a 7 nm shell layer,and the Fe content reached 38.92%.The rMCB removal rate was 83.81%at a concentration of 20 mg·L^(-1),(20±2)℃,a dosage rate of 0.5 g·L^(-1) for nZVI@SiO_(2)-1 and 3 mmol·L^(-1) for PDS.The low concentrations of HA and Cl-showed a facilitative effect on the removal of MCB by the nZVI@SiO_(2)-1/PDS system.In contrast,HCO_(3)-,NO_(3)-and SO_(4)^(2-)showed inhibitory effects,with with HCO_(3)-having the highest inhibitory effect,followed by NO_(3)^(-)and SO_(4)^(2-).The removal effect was good under acidic and neutral conditions and the removal efficiency of MCB was 89.01%at pH 5,while it was only 38.63%at pH 11.The results of the free radical capture(EPR)and competitive radical quenching results showed that the degradation of MCB involved both free radical and non-free radical pathways with the main active species SO_(4)^(·-),·OH,and ^(1)O_(2).The results of the broad-spectrum experiments have shown that the system is effective in removing a wide range of chlorinated hydrocarbons(CHCs)and has good potential for application in practical remediation projects of CHCs-contaminated groundwater.
作者
闫兴雨
王艳
王善虎
莫原野
许伟
刘阳
孟宪荣
施维林
YAN Xingyu;WANG Yan;WANG Shanhu;MO Yuanye;XU Wei;LIU Yang;MENG Xianrong;SHI Weilin(College of Environmental Science and Engineering,Suzhou University of Science and Technology,Suzhou 215009;Suzhou Institute of Environmental Sciences,Suzhou 215009;Suzhou Yifante Environmental Remediation Co.Ltd.,Suzhou 215000)
出处
《环境科学学报》
CAS
CSCD
北大核心
2024年第2期125-135,共11页
Acta Scientiae Circumstantiae
基金
苏州市科技局项目(No.SS202036,SS2019005)
地下水重金属污染纳米生物炭阻控及其数值模拟应用研究(No.2022SS16)。
