共存离子对纳米铁在Cr(Ⅵ)溶液中晶相转化的影响  

Effect of coexisting ions on crystal phase transformation of nanoscale zero-valent iron in chromium-containing solutions

作　　者：戴雨薇 刘静[1,2] 付佳慧 刘爱荣 DAI Yuwei;LIU Jing;FU Jiahui;LIU Airong(College of Environmental Science and Engineering,Tongji University,Shanghai,200092,China;State Key Laboratory of Pollution Control and Resource Reuse,Shanghai,200092,China)

机构地区：[1]同济大学环境科学与工程学院,上海200092 [2]污染控制与资源化研究国家重点实验室,上海200092

出　　处：《环境化学》2024年第5期1640-1650,共11页Environmental Chemistry

基　　金：国家自然科学基金(42073082,41673096);国家重点研发计划项目(2019YFC1805300);国家重点实验室项目(PCRRC20021)资助.

摘　　要：纳米零价铁(nZVI)与水中六价铬[Cr(Ⅵ)]进行反应时,其本身的结构也发生变化,从而影响其效能和性质.本文主要探究Cr(Ⅵ)溶液中共存重金属离子(Co^(2+)、Cd^(2+)、Ni^(2+)、Cu^(2+))和阴离子(Cl^(−)、CO_(3)^(2−)、NO_(3)^(−)、SO_(4)^(2−))对nZVI晶相转化的影响.研究发现,共存的重金属离子均能够促进nZVI氧化,促进nZVI转化为纤铁矿(γ-FeOOH)和针铁矿(α-FeOOH).共存的阴离子对nZVI的晶相影响与铬和阴离子浓度有关.当Cr为10 mg∙L^(−1)时,4种阴离子均抑制nZVI的氧化作用;当Cr为20 mg∙L^(−1)时,NO_(3)^(−)、SO_(4)^(2−)促进nZVI氧化,CO_(3)^(2−)抑制nZVI氧化,低浓度Cl^(−)(20 mg∙L^(−1))促进nZVI晶相转化,高浓度Cl^(−)(200 mg∙L^(−1))抑制Fe(0)转化为γ-FeOOH和γ-Fe_(2)O_(3)、Fe_(3)O_(4)的混合物;当Cr≥50 mg∙L^(−1)时,nZVI氧化受到抑制,此时4种阴离子没有明显作用.该研究对于探讨复杂环境条件下nZVI结构与去除效能之间的关系具有重要意义.When nanoscale zero-valent iron(nZVI)reacts with hexavalent chromium[Cr(Ⅵ)]in water,its own structure also changes,which affects its efficacy and properties.In this paper,the effect of coexistence of heavy metal ions(Co^(2+),Cd^(2+),Ni^(2+),Cu^(2+))and anions(Cl^(−),CO_(3)^(2−),NO_(3)^(−),SO_(4)^(2−))in Cr(Ⅵ)solution on the crystal phase transformation of nZVI was mainly investigated.Results showed that the coexistence of heavy metal ions can promote the oxidation of nZVI and promote the compositions of nZVI to lepidocrocite(γ-FeOOH)and goethite(α-FeOOH).The effect of coexisting anions on the crystal phase of nZVI is related to concentration of chromium and anions.When Cr was 10 mg∙L^(−1),the four anions all inhibited the oxidation of nZVI;when Cr was 20 mg∙L^(−1),NO_(3)^(−),SO_(4)^(2−)promoted the oxidation of nZVI,CO_(3)^(2−)inhibited the oxidation of nZVI,low concentration of Cl^(−)(20 mg∙L^(−1))promotes the crystal phase transformation of nZVI,high concentration of Cl^(−)(200 mg∙L^(−1))inhibits the transformation of Fe(0)into the mixture ofγ-FeOOH and maghemite/magnetite(γ-Fe_(2)O_(3)/Fe_(3)O_(4)).When Cr(VI)≥50 mg∙L^(−1),the oxidation of nZVI is inhibited,and the four anions have no obvious effect at this time.This study had important significance for studying the relationship between the structure and removal efficiency of nZVI under complex environmental systems.

关 键 词：纳米零价铁 Cr(Ⅵ) 共存离子 晶相转化 去除效能 

分 类 号：X-1[环境科学与工程] O6[理学—化学]