A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism

Titanium dioxide (TiO2) photocatalyst was prepared with a sol-gel method and its characterizations were analyzed TiO2 photocatalytic reduction of Cr6+ was investigated in visible light irradiation and reduction mechanisms were calculated. Prepared TiO2 is anatase with a bandgap of about 2.95 eV. Exp...

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Autores principales:	Baoxiu Zhao, Kaixin Zhang, Yue Huang, Qi Wang, Hao Xu, Yilin Wang, Jincheng Li, Tianwen Song, Wenxiang Xia, Jie Liu
Formato:	article
Lenguaje:	EN
Publicado:	IWA Publishing 2021
Materias:	cr3+ cr6+ photocatalytic reduction tio2 visible light Environmental technology. Sanitary engineering TD1-1066
Acceso en línea:	https://doaj.org/article/51c3475ec45a4559962c850b748bac51
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spelling	oai:doaj.org-article:51c3475ec45a4559962c850b748bac512021-11-06T11:01:36ZA novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism0273-12231996-973210.2166/wst.2021.116https://doaj.org/article/51c3475ec45a4559962c850b748bac512021-05-01T00:00:00Zhttp://wst.iwaponline.com/content/83/9/2135https://doaj.org/toc/0273-1223https://doaj.org/toc/1996-9732Titanium dioxide (TiO2) photocatalyst was prepared with a sol-gel method and its characterizations were analyzed TiO2 photocatalytic reduction of Cr6+ was investigated in visible light irradiation and reduction mechanisms were calculated. Prepared TiO2 is anatase with a bandgap of about 2.95 eV. Experimental results display that almost 100% of Cr6+ is removed by visible light-driven TiO2 photocatalytic reduction after 120 min when Cr2O72− initial concentration is 1.0 mg·L−1, TiO2 dosage is 1.0 g·L−1, and pH value is 3. In acidic aqueous solution, HCrO4− is the dominant existing form of Cr6+ and is adsorbed by TiO2, forming a complex catalyst HCrO4−/TiO2 with an increase in wavelength to the visible light zone, demonstrated by UV–Vis diffuse reflection spectroscopy. Based on X-ray photoelectron spectroscopy data, it can be deduced that Cr6+ is adsorbed on the surface of TiO2 and then reduced to Cr3+ in situ by photoelectrons. Self-assembly of HCrO4−/TiO2 complex catalyst and self-reduction of Cr6+ in situ are the key steps to start the visible light-driven TiO2 photocatalytic reduction. Furthermore, TiO2 photocatalytic reduction of Cr6+ fits well with pseudo-first-order kinetics and has the potential application to treat chemical industrial wastewater. HIGHLIGHTS Cr(VI) is efficiently removed by visible light-driven TiO2 photocatalytic reduction reaction.; Photoinduced electrons are the major reductive substance for Cr(VI) removal.; Adsorption, reduction in situ, and desorption are involved in reduction mechanism of Cr(VI).; Photocatalytic reduction of Cr(VI) fits well with pseudo-first-order kinetics and rate constant is calculated.;Baoxiu ZhaoKaixin ZhangYue HuangQi WangHao XuYilin WangJincheng LiTianwen SongWenxiang XiaJie LiuIWA Publishingarticlecr3+cr6+photocatalytic reductiontio2visible lightEnvironmental technology. Sanitary engineeringTD1-1066ENWater Science and Technology, Vol 83, Iss 9, Pp 2135-2145 (2021)
institution	DOAJ
collection	DOAJ
language	EN
topic	cr3+ cr6+ photocatalytic reduction tio2 visible light Environmental technology. Sanitary engineering TD1-1066
spellingShingle	cr3+ cr6+ photocatalytic reduction tio2 visible light Environmental technology. Sanitary engineering TD1-1066 Baoxiu Zhao Kaixin Zhang Yue Huang Qi Wang Hao Xu Yilin Wang Jincheng Li Tianwen Song Wenxiang Xia Jie Liu A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
description	Titanium dioxide (TiO2) photocatalyst was prepared with a sol-gel method and its characterizations were analyzed TiO2 photocatalytic reduction of Cr6+ was investigated in visible light irradiation and reduction mechanisms were calculated. Prepared TiO2 is anatase with a bandgap of about 2.95 eV. Experimental results display that almost 100% of Cr6+ is removed by visible light-driven TiO2 photocatalytic reduction after 120 min when Cr2O72− initial concentration is 1.0 mg·L−1, TiO2 dosage is 1.0 g·L−1, and pH value is 3. In acidic aqueous solution, HCrO4− is the dominant existing form of Cr6+ and is adsorbed by TiO2, forming a complex catalyst HCrO4−/TiO2 with an increase in wavelength to the visible light zone, demonstrated by UV–Vis diffuse reflection spectroscopy. Based on X-ray photoelectron spectroscopy data, it can be deduced that Cr6+ is adsorbed on the surface of TiO2 and then reduced to Cr3+ in situ by photoelectrons. Self-assembly of HCrO4−/TiO2 complex catalyst and self-reduction of Cr6+ in situ are the key steps to start the visible light-driven TiO2 photocatalytic reduction. Furthermore, TiO2 photocatalytic reduction of Cr6+ fits well with pseudo-first-order kinetics and has the potential application to treat chemical industrial wastewater. HIGHLIGHTS Cr(VI) is efficiently removed by visible light-driven TiO2 photocatalytic reduction reaction.; Photoinduced electrons are the major reductive substance for Cr(VI) removal.; Adsorption, reduction in situ, and desorption are involved in reduction mechanism of Cr(VI).; Photocatalytic reduction of Cr(VI) fits well with pseudo-first-order kinetics and rate constant is calculated.;
format	article
author	Baoxiu Zhao Kaixin Zhang Yue Huang Qi Wang Hao Xu Yilin Wang Jincheng Li Tianwen Song Wenxiang Xia Jie Liu
author_facet	Baoxiu Zhao Kaixin Zhang Yue Huang Qi Wang Hao Xu Yilin Wang Jincheng Li Tianwen Song Wenxiang Xia Jie Liu
author_sort	Baoxiu Zhao
title	A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
title_short	A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
title_full	A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
title_fullStr	A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
title_full_unstemmed	A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
title_sort	novel visible light-driven tio2 photocatalytic reduction for hexavalent chromium wastewater and mechanism
publisher	IWA Publishing
publishDate	2021
url	https://doaj.org/article/51c3475ec45a4559962c850b748bac51
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A novel visible light-driven TiO2 photocatalytic reduction for hexavalent chromium wastewater and mechanism

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