Degradation of ortho-toluidine from aqueous solution by the TiO2/O3 process

International Journal of Industrial Chemistry

دوره 8، شماره 1، خرداد 2017، صفحه 101-108

نوع مقاله: research article

شناسه دیجیتال (DOI): https://doi.org/10.1007/s40090-016-0110-z

نویسندگان

Aref Shokri^{* 1}؛ Kazem Mahanpoor²

¹Dezful university

²Department of Chemistry, Faculty of Science, Arak Branch, Islamic Azad University, Arak, Iran

چکیده

In this work, the degradation and mineralization of ortho-toluidine (OT) that is one of the constituents of petrochemical wastewater was investigated by the TiO₂/O₃ process. The influence of some operational parameters such as concentration of pollutant (30–90 mg L⁻¹), initial pH and amounts of TiO₂ was investigated. A radical mechanism with the formation of an anion radical superoxide radical prior to hydroxyl radical is suggested for describing the interaction between ozone and TiO₂. These results were not similar to the ozonation process alone, in which higher pH had a positive effect on the removal of OT because of the generation of hydroxyl radicals. In optimum pH for the ozonation and O₃/TiO₂ processes, the degradation efficiency of the OT was 89.5 and 96%, respectively, at 60 min of reaction. Furthermore, it was made clear that in catalytic ozonation, the degradation efficiency of the OT was higher at neutral pH conditions (pH = 7). The removal of chemical oxygen demand (COD) was increased from 47.5% (only ozonation) to 73% (O₃/TiO₂) after 90 min of reaction. The kinetics of degradation was pseudo-first order; the degradation and relative mineralization of the OT were calculated by HPLC and COD tests, respectively.

کلیدواژه‌ها

TiO2 nanocatalyst؛ Degradation؛ Orthotoluidine (OT)؛ Chemical oxygen demand (COD)؛ Catalytic ozonation