摘要
硫化纳米铁(S-nZVI)是一种具有壳核结构的新型纳米铁(nZVI)改性材料,在多种污染物的去除上表现出超越nZVI的反应活性。本文采用两步合成法制备了S-nZVI,并采用透射电镜-能量色散X射线(TEM-EDX)、X射线衍射(XRD)和X射线光电子能谱分析(XPS)方法对S-nZVI和nZVI进行表征,探讨了不同硫铁摩尔比(n(S)/n(Fe))、初始pH值、试剂投加量和地下水化学成分对nZVI及S-nZVI去除Cr(Ⅵ)的影响。结果表明:S-nZVI具有明显的壳核结构,其Fe0核外层包覆着非晶的硫化亚铁和多硫化物;S-nZVI去除Cr(Ⅵ)的最佳n(S)/n(Fe)为0.14;增加S-nZVI投加量会提高其对Cr(Ⅵ)的去除率,投加量相同时,S-nZVI对Cr(Ⅵ)的去除率显著高于nZVI;提高初始pH值时,S-nZVI和nZVI对Cr(Ⅵ)的去除率均逐渐降低,但在相同pH值条件下,S-nZVI对Cr(Ⅵ)的去除率和去除速率始终高于nZVI,尤其是在pH=5时,S-nZVI仍能去除100%的Cr(Ⅵ),而nZVI只能去除85%;K^+、Na^+、Ca^(2+)、Mg^(2+)、SO_4^(2-)、NO_3^-和Cl-对S-nZVI和nZVI去除Cr(Ⅵ)均有促进作用,但对S-nZVI体系的促进作用更强;HCO_3^-的存在会使溶液的pH值升高从而抑制S-nZVI和nZVI对Cr(Ⅵ)的去除,对nZVI的抑制作用强于S-nZVI。总体来说,S-nZVI对Cr(Ⅵ)的去除率在不同pH值和多种地下水化学组分影响条件下均高于nZVI,因此具有更广泛的应用前景。
Sulfidated nanoscale zerovalent iron(S-nZVI)is a new nZVI modified material with core-shell structure,and exhibits a higher reactivity towards various contaminants than nZVI.In this study,S-nZVI was synthesized by a two-step method.S-nZVI and nZVI were investigated by transmission electron microscope-energy dispersive X-ray spectroscopy(TEM-EDX),X-ray diffraction(XRD)and X-ray photoelectron spectroscopy(XPS).The effects of n(S)/n(Fe),initial pH,reagent dosage and groundwater chemical composition on Cr(Ⅵ)removal by nZVI and S-nZVI were evaluated.The results showed that S-nZVI has obvious core-shell structure,and the core of Fe 0 is coated with amorphous ferrous sulfide and polysulfide.The optimum n(S)/n(Fe)was 0.14 for the reaction between S-nZVI and Cr(Ⅵ).The increased dosage of S-nZVI enhanced Cr(Ⅵ)removal efficiency.With the same dosage,the Cr(VI)removal efficiency by S-nZVI was significantly higher than that by nZVI.When pH increased,the Cr(Ⅵ)removal efficiency by both S-nZVI and nZVI decreased gradually.But the efficiency and removal rate by S-nZVI were always higher than by nZVI under the same pH.Especially at pH=5,S-nZVI removed 100%of Cr(Ⅵ),whereas nZVI removed 85%.K^+,Na^+,Ca^2+,Mg^2+,SO 4^2-,NO 3^-,and Cl^-promoted Cr(Ⅵ)removal by both S-nZVI and nZVI,but more effectively in S-nZVI system.The presence of HCO 3-increased the solution pH,and thus inhibited Cr(Ⅵ)removal more stronger in nZVI than S-nZVI systems.S-nZVI shows a higher efficiency of Cr(Ⅵ)removal than nZVI under the influence of various pH and groundwater chemical components,so it has a broader application prospect.
作者
洪梅
韩旭
王蔷
刘璐
史玉玺
Hong Mei;Han Xu;Wang Qiang;Liu Lu;Shi Yuxi(College of New Energy and Environment,Jilin University,Changchun 130021,China;Key Laboratory of Groundwater Resources and Environment(Jilin University),Ministry of Education, Changchun 130021,China;Bureau of Hydrology Songliao River Water Resources Commission,Changchun 130021,China)
出处
《吉林大学学报（地球科学版）》
EI
CAS
CSCD
北大核心
2018年第6期1821-1830,共10页
Journal of Jilin University：Earth Science Edition
基金
国家自然科学基金项目(41530636)
吉林省科技发展计划项目(20150204045SF)~~
