电化学氧化反应器尺度效应对于抗生素模拟废水降解的影响

Scale effect of electrochemical oxidation reactor on the degradation of antibiotic simulated wastewater

反应器的尺寸对于污水处理效率具有显著的影响,是污水处理从实验室小型反应器到实际中大型反应器应用的关键.本研究建立了尺寸为33.6 cm^(3)(3 cm×8 cm×1.4 cm)的电化学反应器,以掺硼金刚石膜(boron doped diamond,BDD)电极为阳极,对磺胺对甲氧嘧啶(sulfametoxydiazine,SMD)的氧化降解进行实验测试.在实测数据的基础上,利用计算流体力学(Computational fluid dynamics,CFD)软件fluent建立电化学氧化反应器降解SMD的数学模型,率定不同电流密度下的电化学表面反应速率,分析反应器尺寸对污染物流动特征分布和浓度特征分布影响,利用CFD模拟,分别将BDD阳极面积放大100倍、225倍和400倍,探究3种工况下的尺度效应模拟.结果表明,BDD体系降解反应器的尺度效应显著,在20 mA·cm^(−2)的电流密度下持续60 min后,3种BDD阳极体系中SMD的降解率分别达到72.7%、68.0%和40.4%,相比实验室反应器降解能力分别下降5.7%、11.8%和47.6%,建议反应器放大尺度小于200倍以免显著影响降解能力.

The size of reactor has a significant impact on the efficiency of wastewater treatment,which is the key to the application of wastewater treatment from laboratory small reactors to actual medium and large reactors.This study established a size of 33.6 cm^(3)(3 cm×8 cm×1.4 cm)electrochemical reactor,with BDD(Boron Doped Diamond)electrode as anode,to conduct experimental test on the oxidative degradation of sulfamethazine(SMD).On the basis of measured data,the mathematical model of electrochemical oxidation reactor degrading SMD was established by using Computational fluid dynamics(CFD)software fluent,the electrochemical surface reaction rate under different current densities was calibrated,and the influence of reactor size on the distribution of pollutant flow characteristics and concentration characteristics was analyzed.The BDD anode area was magnified by 100 times,225 times and 400 times respectively by using CFD simulation,Explore the scale effect simulation under 3 working conditions.The results showed that the scale effect of the BDD system degradation reactor was significant.After 60 min at a current density of 20 mA·cm^(−2),the degradation rates of SMD in the three BDD anode systems were 72.7%,68.0%and 40.4%,respectively,which decreased by 5.7%,11.8%and 47.6%compared with the degradation capacity of the laboratory reactor.It was suggested that the reactor magnification should be less than 200 times to avoid significant impact on the degradation capacity.