Sedimentation and reuse of titanium dioxide: Application to suspended-photocatalyst reactors
- Washington State Univ., Pullman, WA (United States). Dept. of Civil and Environmental Engineering
- Hanyang Univ., Seoul (Korea, Republic of). Dept. of Chemical Engineering
- Aptus-Westinghouse Co., Salt Lake City, UT (United States)
Titanium dioxide (TiO{sub 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{sub 2} after separation from the reactor effluent. Zeta-potential analysis showed that the zero point of charge (ZPC) of TiO{sub 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{sub 2} sedimentation through coagulating and flocculating the dispersed TiO{sub 2} catalyst at neutral pH. However, two cationic polymers and one anionic polymer were effective in enhancing TiO{sub 2} sedimentation only at pH 3. Using 1,2-bis(2-chloro-ethoxy)ethane as a photocatalytic substrate, ferrous sulfate-coagulated TiO{sub 2} and acid-precipitated TiO{sub 2} had the highest rates of photocatalytic activity after sedimentation.
- Sponsoring Organization:
- USDOE
- OSTI ID:
- 128832
- Journal Information:
- Journal of Environmental Engineering, Journal Name: Journal of Environmental Engineering Journal Issue: 10 Vol. 121; ISSN 0733-9372; ISSN JOEEDU
- Country of Publication:
- United States
- Language:
- English
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