Preprint Article Version 1 This version is not peer-reviewed

Tio2 Assisted Photodegradation for Low Substrate Concentrations and Transition Metal Electron Scavengers

Version 1 : Received: 6 June 2018 / Approved: 6 June 2018 / Online: 6 June 2018 (12:56:35 CEST)

A peer-reviewed article of this Preprint also exists.

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. 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.

Journal reference: ChemEngineering 2018, 2, 33
DOI: 10.3390/chemengineering2030033

Abstract

Some contaminants of emerging concern (CECs) are known to survive conventional wastewater treatment plants, which introduce them back to the environment and can potentially cycle up in drinking water supplies. 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 prominent interest for addressing CECs in aqueous environments. Natural water resources often contain dissolved metal cations concentrations in excess of targeted CEC concentrations. These cations may significantly, adversely impact 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 B dye and dissolved copper cations were studied as reaction surrogates to demonstrate that TiO2 catalyzed degradation for very dilute solutions is very nearly completely due to homogeneous reaction with hydroxyl radicals and that in this scenario the hole trapping pathway has negligible impact. Chemical reaction kinetic studies were then carried out to develop a robust model for RB/metal reactions that is exact in the electron pathways for hydroxyl radical production and metal scavenging.

Subject Areas

TiO2; AOP; photodegradation; semiconductor based photocatalysis; reaction kinetics

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