Author(s): WANG Yanqi, LIU Wen, WANG Ting, NI Jinren, Shenzhen Key Laboratory for Heavy Metal Pollution Control and Reutilization, School of nvironment and Energy, Peking University Shenzhen Graduate School, Key Laboratory of Water and Sediment Sciences, Ministry of Education, Department of Environmental Engineering, Peking University
Pages: 656-668
Year: 2015 Issue:  4
Journal: Journal of Basic Science and Engineering
Keyword:  Fe-TNTs; arsenic; two-site adsorption; photocatalysis;
Abstract: Iron-doped titanate nanotubes( Fe-TNTs) was synthesized through a one-step water-solvent hydrothermal method and used to remove arsenic( As) from aqueous solution via adsorption and photocatalysis. TEM,EDS and XRD analysis confirmed that Fe successfully doped onto TNTs. In addition,Fe-TNTs showed large specific surface area( 162. 8m2/ g) and high isoelectric point( 5. 49),which was benefited to As adsorption. Two-site Langmuir model could better describe the adsorption isotherms of As( Ⅲ) and As( Ⅴ) onto Fe-TNTs,and the maximum adsorption capacity was 17. 67 and 90. 96 mg / g,respectively. Large As( Ⅴ) adsorption capacity by FeTNTs was due to electrostatic attraction at low p H,while the adsorption mechanism of As( Ⅲ)was complexation. Fe doping reduced the band gap of TNTs,and moreover,Fe3 +could act as a temporary capture agent for electron-hole pairs,thus preventing electron-hole pair recombination and promoting photocatalytic performance of TNTs. After 30 min of the photocatalytic reaction,As( Ⅲ) was completely oxidized to As( Ⅴ),which was then efficiently adsorbed onto Fe-TNTs.Therefore,arsenic removal process by Fe-TNTs was a simultaneous process of photocatalysis and adsorption.