The electrochemical oxidation of biologically treated citric acid wastewater in a continuous-flow three-dimensional electrode reactor (CTDER)

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• 作者：Xinyang Li ; Wei Zhu ; Chengwen Wang ; Liwei Zhang ; Yi Qian ; Fangqin Xue ; Yue Wu
• 关键词：Advanced treatment ; Secondary industrial effluent ; Continuous-flow mode ; Ti/RuO2&ndash ; IrO2&ndash ; TiO2&ndash ; SnO2 anode ; Granular activated carbon
• 刊名：Chemical Engineering Journal
• 出版年：2013
• 出版时间：October, 2013
• 年：2013
• 卷：232
• 期：Complete
• 页码：495-502
• 全文大小：1498 K

文摘

In this study, we constructed a continuous-flow three-dimensional electrode reactor (CTDER) to remove organic compounds from biologically-treated citric acid wastewater. We analyzed the effects of the residence time, current density, initial pH, and airflow rate on the reactor¡¯s energy consumption (E_s), general current efficiency (GCE), and ability to remove the chemical oxygen demand (COD). We determined that the optimal operation conditions for the reactor included a residence time of 5 min, a current density of 40 mA cm^?2, and an initial pH of 5. Under these conditions, we determined that 55.7 % of COD was removed. The resulting COD of the effluent was within the National Discharge Standard of China (COD < 100 mg L^?1), and the E_s and GCE were 274.8 kW h kg COD^?1 and 16.2 % , respectively. We also found that aeration in the CTDER negatively affected COD removal due to the short-circuiting of the fluid. Further investigation revealed that the CTDER could produce a steady effluent quality where the organic compounds were degraded primarily via the indirect electrochemical oxidation of humic acid-like substances in the citric acid wastewater. Our results demonstrate that the CTDER is a highly efficient system for the electrochemical treatment of biologically-treated citric acid wastewater.