摘要
以乙醇相硫化氢为硫化试剂,通过液相化学还原法制备了硫化纳米零价铁(S-nZVI-H_(2)S-Ethanol),并系统研究了硫化时间对其表面性质、电化学性能、抑氢性能及脱氯效果.结果表明,随着硫化处理时间的增加,表面生成鳞片状铁硫化合物(FeSx),颗粒比表面积显著增加,XPS分析表明,硫化处理处理时间的增加,颗粒表面Fe-S含量呈现先增加后降低的趋势,Fe-O含量则相反.电化学分析结果显示,S12h的S-nZVI-H_(2)S-Ethanol的电荷转移阻抗最小,腐蚀电位(-0.923V)最低,说明不同硫化时间的颗粒呈现不同的电子传输效率和还原能力.析氢实验表明,硫化处理显著抑制了析氢反应,析氢速率随硫化时间延长先降低后趋于稳定.三氯乙烯(TCE)脱氯实验表明,nZVI和S-nZVI-H_(2)S-Ethanol的脱氯反应均符合伪一级动力学模型,S2h、S12h和S24h的表观动力学常数(k_(obs))分别为1.4/h、0.81/h和0.48/h,显著高于nZVI(0.025/h).通过β-消除反应和氢化反应影响降解过程中产物分布,降解产物主要为乙炔、乙烯、乙烷和长链烃(C_(3)-C_(6)).综上,乙醇相硫化氢硫化处理显著提升了nZVI的降解性能,不同硫化时间的S-nZVI-H_(2)S-Ethanol的颗粒表面性质及其脱氯效果研究为优化材料在环境修复中的性能提供了重要依据.
This study employed H_(2)S in an ethanol-phase as a sulfidation reagent to synthesize sulfidated nanoscale zero-valent iron(S-nZVI-H_(2)S-Ethanol)through a liquid-phase chemical reduction approach.A systematic investigation was conducted to examine the effects of sulfidation time duration on the material’s surface characteristics,electrochemical properties,hydrogen suppression capability,and dechlorination performance.The results revealed that prolonged sulfidation treatment led to the formation of flake-like iron-sulfur compounds(FeSx)on the particle surfaces,accompanied by a significant increase in specific surface area.XPS analysis demonstrated a non-monotonic relationship between sulfidation time and surface composition:Fe-S content initially increased before decreasing,while Fe-O content exhibited the inverse trend.Electrochemical characterization indentified the S-nZVI-H_(2)S-Ethanol(S12h)exhibited optimal performance,with the lowest charge transfer impedance and the lowest corrosion potential(-0.923V),suggesting enhanced electron transfer efficiency and reductive capacity.Hydrogen evolution experiments confirmed that sulfidation effectively suppressed the hydrogen evolution reaction,with the hydrogen generation rate decreasing initially before stabilizing with extended treatment time.In TCE dechlorination experiments,both nZVI and S-nZVI-H_(2)S-Ethanol followed pseudo-first-order kinetics,demonstrating markedly higher apparent rate constants(kb:1.4/h,0.81/h,and 0.48/h for S2h,S12h,and S24h,respectively)compared to pristine nZVI(0.025/h).The degradation product distribution of trichloroethylene revealed that the degradation pathways were governed by competingβ-elimination and hydrogenation reactions,yielding primarily acetylene,ethylene,ethane,and long-chain hydrocarbons(C_(3)-C_(6)).These results collectively demonstrated that ethanol-phase H_(2)S sulfidation significantly enhances nZVI’s degradation performance.The comprehensive examination of S-nZVI-H_(2)S-Ethanol’s surface properties and dechlorination efficiency across varying sulfidation durations provides crucial insights for optimizing material design in environmental remediation applications.
作者
李晓源
邓一荣
王贺丽
吴俭
陆海建
LI Xiao-yuan;DENG Yi-rong;WANG He-li;WU Jian;LU Hai-jian(Guangdong-Hong Kong-Macao Laboratory of Soil Pollution Fate and Risk Management in Earth's Critical Zone,Guangdong Provincial Academy of Environmental Science,Guangdong Key Laboratory of Contaminated Site Environmental Management and Remediation,Guangzhou 510045,China)
出处
《中国环境科学》
北大核心
2025年第10期5471-5479,共9页
China Environmental Science
基金
国家重点研发计划项目(2022YFC3703105,2023YFC3709700)
广东省环保专项资金项目(粤财预〔2024〕4号)。
关键词
纳米零价铁
乙醇相硫化氢
硫化时间
三氯乙烯
脱氯
nanoscale zero-valent iron
ethanol-phase H_(2)S
sulfidation time
trichloroethylene
dechlorination
