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ChemEngineering 2018, 2(3), 33; https://doi.org/10.3390/chemengineering2030033

TiO2 Assisted Photodegradation for Low Substrate Concentrations and Transition Metal Electron Scavengers

1
Civil and Environmental Engineering, Tennessee State University, Nashville, TN 37209, USA
2
Mechanical Engineering, Tennessee State University, Nashville, TN 37209, USA
*
Author to whom correspondence should be addressed.
Received: 6 June 2018 / Revised: 13 July 2018 / Accepted: 17 July 2018 / Published: 21 July 2018
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Abstract

Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment, which introduces them back to the environment, allowing them to potentially cycle into drinking water. This is especially concerning because of the inherent ability of some CECs to induce physiological effects in humans at very low doses. Advanced oxidation processes (AOPs) such as TiO2-based photocatalysis are of great interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cation concentrations in excess of targeted CEC concentrations. These cations may significantly adversely impact the degradation of CECs by scavenging TiO2 surface generated electrons. Consequently, simple pseudo-first-order or Langmuir-Hinshelwood kinetics are not sufficient for reactor design and process analysis in some scenarios. Rhodamine Basic Violet 10 (Rhodamine B) dye and dissolved [Cu2+] cations were studied as reaction surrogates to demonstrate that TiO2-catalyzed degradation for very dilute solutions is almost entirely due to the homogeneous reaction with hydroxyl radicals, and that in this scenario, the hole trapping pathway has a negligible impact. Chemical reaction kinetic studies were then carried out to develop a robust model for RB-[Cu2+] reactions that is exact in the electron pathways for hydroxyl radical production and electron scavenging. View Full-Text
Keywords: TiO2; AOP; photodegradation; semiconductor based photocatalysis; reaction kinetics TiO2; AOP; photodegradation; semiconductor based photocatalysis; reaction kinetics
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This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
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Alsaud, H.A.; Abibat, A.E.; Painter, R.; Sharpe, L.; Hargrove, S.K. TiO2 Assisted Photodegradation for Low Substrate Concentrations and Transition Metal Electron Scavengers. ChemEngineering 2018, 2, 33.

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