MnO2催化臭氧氧化模拟草酸废水

Catalytic Ozonation of Simulated Oxalic Acid Wastewater Using MnO2

比较了单独臭氧氧化、MnO2催化剂吸附和MnO2催化臭氧氧化3个体系对模拟草酸废水COD的去除效果,考察催化剂投加量对COD去除率的影响,并建立和验证了草酸氧化降解中的独立反应式.实验结果表明:单独臭氧氧化、MnO2催化剂吸附和MnO2催化臭氧氧化3个体系对模拟草酸废水COD的去除率分别为4.94%、20.83%和44.44%.MnO2催化剂最佳投加量为0.500 g/L时,COD(草酸初始质量浓度500 mg/L,初始COD质量浓度89 mg/L,反应时间1 h)的去除率高达85.87%,由于MnO2催化O3产生·OH,MnO2/O3体系对模拟草酸废水COD的去除率明显提高.依据化学计量矩阵方法,验证并确立了草酸氧化降解过程的独立反应式.动力学理论计算和实验结果均表明,MnO2催化臭氧氧化模拟草酸废水COD的降解过程符合准一级动力学方程(R^2>0.9).

COD removal of simulated oxalic acid wastewater was studied in three different systems:ozone oxidation,MnO2 catalyst adsorption and MnO2 catalytic ozonation.The effect of catalyst dosage on COD removal rate was tested,and independent reaction formula for the degradation of oxalic acid was verified.The results showed that the COD removal rate of oxalic acid by ozone oxidation alone,MnO2 catalyst adsorption and catalytic ozone oxidation were 4.94%,20.83%and 44.44%,respectively.The optimum dosage of catalyst MnO2 was 0.500 g/L,and the removal rate of COD(initial concentration of oxalic acid was 500 mg/L,initial COD concentration was 89 mg/L,and reaction time was 1 h)could be up to 85.87%.Owing to the·OH produced by MnO2-catalyzed O3,the COD degradation rate could be significantly improved in the MnO2/O3 process.Independent reaction formulas for the oxidative degradation process of the oxalic acid were established and verified with the stoichiometric matrix method.Both kinetic theory calculation and experimental results show that the COD degradation process of simulated oxalic acid wastewater in MnO2/O3 system is in accordance with the quasi-first-order kinetic equation(R^2>0.9).