Sedimentation and Reuse of Titanium Dioxide: Application to Suspended-Photocatalyst Reactors
Publication: Journal of Environmental Engineering
Volume 121, Issue 10
Abstract
Titanium dioxide (TiO 2 ) sedimentation, enhanced through charge neutralization and coagulation/flocculation with metal salts and polymers, was investigated to evaluate the potential for its recovery from the effluents of suspended photocatalyst reactors. The application emphasizes reuse of the TiO 2 after separation from the reactor effluent. Zeta-potential analysis showed that the zero point of charge (ZPC) of TiO 2 suspensions was at pH 2.5, and settling rates for the photocatalyst were greatest at ±0.5 pH unit of the ZPC. Aluminum sulfate, ferric chloride, and ferrous sulfate were effective in enhancing TiO 2 sedimentation through coagulating and flocculating the dispersed TiO 2 catalyst at neutral pH. However, two cationic polymers and one anionic polymer were effective in enhancing TiO 2 sedimentation only at pH 3. Using 1,2-bis(2-chloroethoxy)ethane as a photocatalytic substrate, ferrous sulfate-coagulated TiO 2 and acid-precipitated TiO 2 had the highest rates of photocatalytic activity after sedimentation.
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Published In
Journal of Environmental Engineering
Volume 121 • Issue 10 • October 1995
Pages: 730 - 735
Copyright
Copyright © 1995 American Society of Civil Engineers.
History
Published online: Oct 1, 1995
Published in print: Oct 1995
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