Kinetics of glyphosate degradation in glyphosate wastewater over nitrogen-doped activated carbon catalyst in an upflow fixed bed reactor

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• 作者：Bo Xing ; Honglin Chen ; Xiaoming Zhang
• 关键词：Catalytic wet oxidation ; Nitrogen ; doped activated carbon ; Fixed bed reactor ; Kinetics ; Glyphosate wastewater ; Organic phosphorus
• 刊名：Reaction Kinetics, Mechanisms and Catalysis
• 出版年：2017
• 出版时间：February 2017
• 年：2017
• 卷：120
• 期：1
• 页码：95-107
• 全文大小：
• 刊物类别：Chemistry and Materials Science
• 刊物主题：Catalysis; Physical Chemistry; Industrial Chemistry/Chemical Engineering;
• 出版者：Springer Netherlands
• ISSN：1878-5204
• 卷排序：120

文摘

Catalytic wet oxidation (CWO) of glyphosate (PMG) wastewater over a nitrogen-doped activated carbon catalyst was performed in an upflow fixed bed reactor at mild temperature (35–125 °C) and oxygen partial pressure (0.05–0.25 MPa). The catalytic performance was characterized by PMG and organic phosphorus (OP) conversion. All CWO experiments were under kinetic control by choosing suitable average particle size (0.3 mm, 40–80 mesh) and gas flow rate (500 mL min−1). A power law kinetic model was developed to describe PMG and OP conversion, assuming first order kinetics with respect to PMG and OP. This model and its calculated parameters successfully predicted PMG and OP conversion. The obviously different rate constant and activation energy for PMG and OP conversion suggested that removal of the intermediate of aminomethylphosphonic acid is the control reaction for OP conversion. Finally, the competitive oxidation of formaldehyde was insignificant and this model also proved a satisfactory description for treatment of the real PMG wastewaters. OP conversion for the different PMG wastewaters can reach over 90% at mild conditions (125 °C, 0.2 MPa of oxygen partial pressure, 25 min of liquid space time).