Author(s)

Harufumi Suzuki, Shoichi Yamagiwa, Sadao Araki, Hideki Yamamoto^*

Department of Chemical, Energy and Environmental Engineering, Faculty of Environmental and Urban Engineering, Kansai University, Osaka, Japan.

Studies to decompose persistent organic pollutants in wastewater from chemical factories by using Advanced Oxidation Processes (AOPs) have recently been performed. Oxidation reactions involving ozone and •OH radicals and cleavage caused by UV are the main decomposition reactions that occur in AOPs using ozone and UV. The mechanisms through which organic compounds are decomposed in AOPs are complicated and difficult to understand because various decomposition reactions occur simultaneously. The Total Organic Carbon (TOC) removal efficiencies achieved in several different AOPs were evaluated in this study. The TOC removal efficiencies were different for organic compounds with different chemical structures. The TOC was more effectively removed when aromatic compounds were treated using the O₃-UV-TiO₂ process than when using the other AOPs, and the TOC was removed more effectively by the O₃-UV process than by the UV-TiO₂ process. However, the TOC was removed more effectively when open-chain compounds were treated using the UV-TiO₂ process than using the O₃-UV process, and the UV-TiO₂ and O₃-UV-TiO₂ processes resulted in similar TOC removal efficiencies. Therefore, it is necessary to use the O₃-UV-TiO₂ process to decompose aromatic compounds as quickly as possible. On the other hand, the UV-TiO₂ process degraded the open-chain compounds most effectively, and the O₃-UV-TiO₂ process did not need to decompose open-chain compounds. Moreover, the TOC of aromatic compounds was removed more slowly than that of open-chain compounds. The TOC removal efficiency increased with decreasing the number of carbon atoms in the molecule. The TOC removal efficiencies increased in order of the organic compounds containing methyl groups, aldehyde groups and carboxyl groups. The removal of the TOC when organic compounds were treated using the O₃-UV-TiO₂ process followed pseudo-zero-order kinetics.

Advanced Oxidation Process, Ozone, Hydroxyl Radical, Decomposition Efficiency, Water Treatment

Suzuki, H. , Yamagiwa, S. , Araki, S. and Yamamoto, H. (2016) Effects of Advanced Oxidation Processes on the Decomposition Properties of Organic Compounds with Different Molecular Structures in Water. Journal of Water Resource and Protection, 8, 823-834. doi: 10.4236/jwarp.2016.89067.