摘要
随着体系ｐＨ值增大，Ｃｒ（ＶＩ）离子在ＴｉＯ２表面的吸附下降．当Ｃｒ（ＶＩ）离子初始浓度为３００μｍｏｌ／Ｌ时，其在ＴｉＯ２表面具有最大值吸附．Ｈ２ＰＯ４－阴离子及乙酸的存在对Ｃｒ（ＶＩ）离子的吸附有阻抑作用，甲酸存在会提高Ｃｒ（ＶＩ）离子的吸附．Ｃｒ（ＶＩ）离子在ＴｉＯ２半导体催化剂表面的光催化还原受体系的酸度影响较大．Ｈ２ＰＯ４－阴离子或Ｍｎ２＋离子存在会降低Ｃｒ（ＶＩ）离子的光催化还原效率．在太阳光照下，Ｃｒ（ＶＩ）离子在ＴｉＯ２上的光催化还原也可实现．通过调节反应结束后水溶液的酸碱度，Ｃｒ（ＶＩ）离子得以消除．反应后催化剂经酸处理，其活性恢复并可重复使用．
Adsorption of Cr(VI) on TiO_2 decreased with the increase of the suspension pH.The largest Cr(VI) adsorption appeared when its initial concentration was about 300 μmol/L.The existence of H_2PO_4^- anion and acetic acid decreased the adsorption efficiency of Cr(VI),and formic acid promoted its adsorption efficiency. Other organic molecules had noninterference with Cr(VI) adsorption,and competitive adsorption did not happen between them.System pH had remarkable effects on photocatalytic reduction of Cr(VI) on TiO_2.H_2PO_4^- anion and Mn^2+ cation both had inhibition on Cr(VI) reduction. Different organic compounds had different influences on Cr(VI) reduction because of their different electrical properties.Under the sunlight irradiation,Cr(VI) reduction was also observed on TiO_2 photocatalyst.After separation of the catalyst,chromium was removed and detoxified from the waste water by adjusting the pH of the system.TiO_2 photocatalyst was reactivated and reused after it was washed in acidic medium.
出处
《环境科学》
EI
CAS
CSSCI
CSCD
北大核心
1998年第3期80-83,共4页
Environmental Science
关键词
吸附
光催化
铬离子
二氧化钛
废水处理
Cr(VI) ion,adsorption,photocatalytic reduction,detoxification,TiO_2 photocatalyst.
