零价铝/铁饱和凹凸棒复合材料活化氧化剂降解4-氯酚的研究

Degradation of 4-chlorophenol through activating oxidants by zero-valent Al/Fe-saturated attapulgite composites

零价铝是高级氧化技术中极具潜力的一种非均相催化剂,然而其表面固有的致密氧化膜影响其电子传递而限制其应用.本文将一种铁饱和的商品化粘土凹凸棒(FeATP)与微米零价铝(mZVAl)球磨复合制得mZVAl-FeATP复合材料,并探究其对H_(2)O_(2)、过硫酸盐及过一硫酸盐(PMS)活化降解4-氯酚(4-CP)效果.mZVAl-FeATP对PMS具有最佳活化性能,因此系统探究了mZVAl-FeATP/PMS体系的氧化性能与相关机理.结果表明,该体系在pH 3.00~9.00间均能快速降解4-CP,主要活性物质为SO_(4)^(•−),•OH和^(1)O_(2)也参与反应.mZVAl作为电子供体,不仅还原mZVAl-FeATP表面吸附态Fe(Ⅲ)生成Fe(Ⅱ)用于活化PMS,还可促进Fe(Ⅲ)/Fe(Ⅱ)循环.除了4-CP,该体系对不同有机污染物在不同水质条件下均有着良好的氧化降解性能,具有较好的应用普适性;mZVAl-FeATP还可通过二次球磨再生恢复其催化活性.综上,该工作不仅克服了ZVAl氧化膜对其电子传导的阻碍,且发挥了粘土矿物独特层间结构的优势,使得mZVAl-FeATP在水环境修复中有着良好的应用前景.

Zero-valent aluminum(ZVAl)is a promising heterogeneous catalyst in advanced oxidation technologies.However,the natural dense oxide layer of ZVAl impedes electron transfer from the core metal.Herein,a commercial clay,that is,attapulgite(ATP),with the advantages of abundant yield and low cost,was treated with FeCl_(3) through saturated ion-exchange to enhance its Fe content,and was further mixed with micro-sized ZVAl(mZVAl)to obtain a mZVAl/Fe-saturated ATP composite(mZVAl-FeATP).It was explored to activate three oxidants,namely,H_(2)O_(2),persulfate(PS),and peroxymonosulfate(PMS),for 4-chlorophenol(4-CP)degradation.The mZVAl-FeATP presented better activation ability to PMS than to PS and H_(2)O_(2).The synergistic oxidative degradation performance and mechanisms of the mZVAl-FeATP/PMS system were systematically explored.The results showed that the mZVAl-FeATP/PMS system can quickly degrade 4-CP at pH ranging from 3.00 to 9.00.The main reactive species were SO_(4)•,•OH and ^(1)O_(2).During the reaction process,mZVAl,acted as an electron donor,could not only reduce the adsorbed Fe(Ⅲ)to Fe(Ⅱ)on the surface of mZVAl-FeATP for PMS activation,but also promote Fe(Ⅲ)/Fe(Ⅱ)cycle.mZVAl-FeATP/PMS system with a good general applicability could effectively degrade various organic contaminants in different water sources,in addition to 4-CP.Moreover,the catalytic reactivity of mZVAl-FeATP can be restored by a second ball milling process.In short,this work provided a simple and environmentally-friendly modification strategy,which can overcome the obstacle of electron transferring caused by ZVAl’s oxide film and make full use of interlayer structure of clay minerals,thereby broadening the applications of zero-valent aluminum and clay minerals in the field of water environmental remediation.