摘要
硫化是零价铁(ZVI)除污活性的重要强化方法,以重铬酸盐Cr(Ⅵ)为目标污染物,利用球磨法合成了硫化零价铁(SZVI^(bm))。研究结果表明,随着S摩尔分数/Fe摩尔分数升高,SZVI^(bm)去除Cr(Ⅵ)的反应活性呈先升高后下降的趋势;当S摩尔分数/Fe摩尔分数为0.10时,SZVI^(bm)的反应速率达到最优(0.0268 min^(-1)),其是未硫化球磨零价铁(ZVI^(bm))反应速率的7.24倍;结合X射线光电子能谱(XPS)和电化学阻抗谱的表征结果,明确了硫化作用协同球磨可降低ZVI的界面阻抗,对应阻抗值从875.6Ω(ZVI^(bm))降至353.9Ω(SZVI^(bm)),进而将Cr(Ⅵ)还原为Cr(Ⅲ)的程度从55.61%(ZVI^(bm))提升至77.18%(SZVI^(bm));进一步地,通过相关性分析,揭示了S_(2)^(2-)/S^(2-)、吸附态Fe^(2+)以及结构态Fe^(2+)/Fe^(3+)是SZVI^(bm)增效体系中的关键活性物种(R^(2)>0.85),其可形成导电性的FeS_(x)和Fe_(3)O_(4),进而介导铁电子从Fe^(0)至Cr(Ⅵ)转移,最终实现SZVI^(bm)对Cr(Ⅵ)的增效还原。
Sulfidation is an important method for enhancing the reactivity of zero-valent iron(ZVI)toward contaminants.Taking dichromate Cr(Ⅵ)as the target pollutant,the SZVI was synthesized through ball-milling method(i.e.,SZVI^(bm))and found that its reactivity toward Cr(Ⅵ)showed a first increasing and then decreasing with the increase of the S molar ratio/Fe molar ratio.The optimal reaction rate of SZVI^(bm)(0.0268 min^(-1))was achieved with the S molar ratio/Fe molar ratio at 0.10,which was 7.24 times that of the ball-milled ZVI without sulfidation(i.e.,ZVI^(bm)).Combined with the characterization results of X-ray photo-electron spectroscopy(XPS)and electrochemical impedance spectroscopy,it was confirmed that the coupling of ball-milling with sulfidation could decrease the electrical resistance from 875.6Ωof the ZVI^(bm)to 353.9Ωof the SZVI^(bm),thereby promoting the reduction of Cr(Ⅵ)into Cr(Ⅲ)from 55.61%by the ZVI^(bm)to 77.18%by the SZVI^(bm).Furthermore,the correlation analysis revealed that the S_(2)^(2-)/S^(2-),adsorbed Fe^(2+),and structured Fe^(2+)/Fe^(3+)are the key reactive species(R^(2)>0.85)in the enhanced system of SZVI^(bm),which can form conductive FeS_(x)and Fe_(3)O_(4),and thus mediate the electron transfer of Fe^(0)toward Cr(Ⅵ),ultimately enhancing the reduction of Cr(Ⅵ)by SZVI^(bm).
作者
张敏
李震
李锦祥
Zhang Min;Li Zhen;Li Jinxiang(Suzhou Polytechnic Institute of Agriculture,Suzhou 215008,China;School of Environmental and Biological Engineering,Nanjing University of Science and Technology,Nanjing 210094,China)
出处
《南京理工大学学报》
北大核心
2026年第1期114-120,共7页
Journal of Nanjing University of Science and Technology
基金
苏州农业职业技术学院博士提升计划科研启动基金(BS[2022]24)
苏州农业职业技术学院科研创新团队专项资助(CXTD202407)。
关键词
零价铁
球磨
硫化
铁硫活性物种
相关性分析
zero-valent iron
ball-milling
sulfidation
iron and sulfur reactive species
correlation analysis
