摘要
由工业生产引起的铬污染是环境领域面临的一大挑战.二氧化钛(TiO_(2))材料因其吸附催化的双重作用在铬的去除方面具有潜在应用前景.利用溶剂热法合成高指数晶面TiO_(2){201},对其进行SEM、TEM、XRD及XPS表征,并用于Cr(Ⅲ/Ⅵ)的吸附及Cr(Ⅵ)的光催化还原,以达到从水体中去除铬的目的.所合成的TiO_(2){201}为锐钛矿相,呈蒲公英状的层级结构.Langmuir吸附等温线结果表明,TiO_(2){201}对Cr(Ⅲ)和Cr(Ⅵ)的最大吸附量分别为22.7 mg·g^(-1)和13.2 mg·g^(-1),Freundlich模型拟合结果表明TiO_(2){201}对Cr(Ⅲ)和Cr(Ⅵ)的吸附均易于进行,其1/n均小于0.5.在紫外光照条件下,TiO_(2){201}作为光催化剂可将毒性较强且吸附去除效果较差的Cr(Ⅵ)还原成Cr(Ⅲ),并以Cr(OH)3及Cr2O3的形式沉淀在TiO_(2)表面,XPS表征结果进一步证实了表面沉淀的存在.为探明TiO_(2){201}光催化还原Cr(Ⅵ)的机制,分别研究光生空穴淬灭剂(EDTA-2Na)和光生电子淬灭剂(KBr O3)对Cr(Ⅵ)还原效率的影响,证明Cr(Ⅵ)的还原是由光生电子引起.
Chromium(Cr)contamination caused by industrial manufacturing poses a severe challenge in the environment.Titanium dioxide(TiO_(2))has potential application in Cr removal due to its adsorption and photocatalytic performance.High-index TiO_(2) with exposed{201}facet was synthesized using the solvothermal method and characterized by SEM,TEM,XRD,and XPS.The adsorption of Cr(Ⅲ/Ⅵ)and photocatalytic reduction of Cr(Ⅵ)on TiO_(2){201}was examined for the removal from water.The synthesized TiO_(2){201}was constructed by a dandelion-like hierarchical structure.The adsorption isotherms of Cr(Ⅲ)and Cr(Ⅵ)on TiO_(2){201}conformed to the Langmuir model,with maximum adsorption capacities of 22.7 mg·g^(-1) and 13.2 mg·g^(-1),respectively.The best fitted results from the Freundlich model show that the adsorption of Cr(Ⅲ)and Cr(Ⅵ)on TiO_(2){201}were favorable with the parameter of 1/n less than 0.5.The results of photocatalytic reduction show that TiO_(2){201}can reduce Cr(Ⅵ)to Cr(Ⅲ)under UV irradiation,and Cr(Ⅲ)was further precipitated on the surface of TiO_(2) in the form of Cr(OH)3 and Cr2 O3,which was evidenced by XPS characterization.To explore the mechanism of photocatalytic reduction of Cr(Ⅵ),the effect of scavengers for photogenerated holes(EDTA-2 Na)and electrons(KBr O3)on Cr(Ⅵ)reduction was studied,and the results suggested that photogenerated electrons were the main reductant.
作者
钟德健
张建锋
李尧
谢晓丹
ZHONG De-jian;ZHANG Jian-feng;LI Yao;XIE Xiao-dan(Shaanxi Key Laboratory of Environmental Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China;School of Environmental and Municipal Engineering,Xi'an University of Architecture and Technology,Xi'an 710055,China)
出处
《环境科学》
EI
CAS
CSCD
北大核心
2019年第2期701-707,共7页
Environmental Science
基金
国家重点研发计划项目(2017YFC0403403-3/01)
作者简介
钟德健(1993~),男,硕士研究生,主要研究方向为吸附及光催化去除铬,E-mail:793401364@qq.com;通信作者:张建锋,E-mail:zhangjianfeng@xauat.edu.cn.
