Photocatalytic degradation of highly refractive phenolic polymer – Mechanistic insights as revealed by Electron Spin Resonance (ESR) and solid-state 13C NMR spectroscopy
| Autor: | Janardhanam Sridevi, Sundaramoorthy Sundarapandiyan, B. Chandrasekaran, Palanivel Saravanan, Guntamadugu Bhaskar Raju, Thankaswamy Shiny Renitha |
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| Rok vydání: | 2017 |
| Předmět: |
General Chemical Engineering
Radical Kinetics Batch reactor Inorganic chemistry 02 engineering and technology General Chemistry Nuclear magnetic resonance spectroscopy 010402 general chemistry 021001 nanoscience & nanotechnology Photochemistry 01 natural sciences Industrial and Manufacturing Engineering 0104 chemical sciences Catalysis chemistry.chemical_compound Adsorption chemistry Photocatalysis Environmental Chemistry Hydroxyl radical 0210 nano-technology |
| Zdroj: | Chemical Engineering Journal. 313:1112-1121 |
| ISSN: | 1385-8947 |
| Popis: | The degradation of phenolic syntan by photocatalytic process was studied in a re-circulated batch reactor. Degradation was followed by analysing the Total Organic Carbon (TOC) of syntan solution. The effect of solution pH and the initial concentration of phenolic syntan on photocatalytic degradation rate were discussed. It was observed that the degradation is better under alkaline pH and very low concentration of phenolic syntan. The adsorption of phenolic syntan on TiO2 surface was also considered using in situ ATR FT-IR spectroscopy. It was observed that the adsorption of syntan on TiO2 catalyst is prominent at acidic pH. Poor degradation under acidic conditions was attributed to the adsorbed syntan which act as barrier for the penetration of UV radiation. The generation of hydroxyl free radicals during photo-oxidation was investigated by ESR spectroscopy and found that above pH 9.0 is more congenial for hydroxyl radical generation. The degradation of phenolic syntan was found to follow the first-order kinetics. The samples of syntan solution collected during the course of photocatalysis, were analyzed by NMR spectroscopy to understand the degradation path. The presence of aromatic moiety in the samples clearly revealed that the degradation is incomplete even after three hours of photocatalysis. Since the degradation is incomplete, electro-oxidation was attempted to achieve the complete mineralization of phenolic syntan. |
| Databáze: | OpenAIRE |
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