电催化法对分散染料废水的降解效能与倒极除垢效果

Degradation of disperse dye wastewater by electrocatalysis and descaling effect by reversing electrodes

根据分散染料废水酸性强、氯离子浓度高、电导率高的特点,在不同运行工况下,通过建立效能比指标对电催化氧化效果进行综合评价,从3种修饰钛基电极中优选催化活性高的阳极,并确定其反应参数;考察倒极运行的除垢效果及对水质的影响,确定运行方式。研究表明:Ru+Ir阳极的效能比随pH的升高而增加,并在pH>5.0时高于Pt+Ir阳极的效能比;Ta+Ir阳极的效能比在不同pH下均低于Pt+Ir、Ru+Ir阳极。优选出Pt+Ir阳极,确定其反应参数pH为7,极板间距为1 cm,电流密度为20 m A/cm^2,反应时间为30 min,此时,COD_(Cr)去除率可达31.9%,效能比为3.68%/(kW·h/t),能耗为8.66 kW·h/t,运行模式按"反应30~60 min,倒极5~10 min"的周期运行。

According to the characteristics of strong acidity,high chloride ion concentration and high conductivity of disperse dyes wastewater,the ratio of COD removal rate to energy consumption（ CRR/EC） was established to evaluate the effect of electrocatalysis oxidation in different operating conditions. The anode with high catalytic activity was selected from three kind of mixed metal oxide（ MMO） coated Ti-based electrodes,and the reaction parameters were determined. The experiments of brief reversing electrode operation were carried out to investigate the descaling effect and the influence on the water quality,and the operation mode was determined. Research shows that CRR/EC of Ti-based electrodes modified by Ru ＋ Ir mixed metal oxide increases with the rise of pH value,higher than that modified by Pt ＋ Ir mixed metal oxide when pH 5. The CRR/EC of Ti-based electrodes modified by Ta ＋ Ir mixed metal oxide is lower than that modified by Pt ＋ Ir or Ru ＋ Ir mixed metal oxide under different pH conditions. Ti-based electrodes modified by Pt ＋ Ir mixed metal oxide was screened out and pH of 7,plate distance of 1 cm,current intensity of 8. 64 m A/cm^2,electrolysis time of 30 min were taken as the optimum conditions. Under the optimum conditions,the CRR can reach 31. 9%,CRR/EC is 3. 68%/（ kW·h/t）,and energy consumption is 8. 66 kW·h/t. The operation mode is set at the cycle reaction of that reverses 5-10 min after every 30-60 min.