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

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• 作者：Aref Shokri ; Kazem Mahanpoor
• 关键词：TiO2 nanocatalyst ; Degradation ; Ortho ; toluidine (OT) ; Chemical oxygen demand (COD) ; Catalytic ozonation
• 刊名：International Journal of Industrial Chemistry
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：8
• 期：1
• 页码：101-108
• 全文大小：720KB
• 刊物主题：Industrial Chemistry/Chemical Engineering; Polymer Sciences; Nanochemistry; Environmental Chemistry;
• 出版者：Springer Berlin Heidelberg
• ISSN：2228-5547
• 卷排序：8

文摘

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.