真空紫外/曝气氧化降解苯甲羟肟酸模拟废水

Effect of oxidative degradation of benzoic acid simulated wastewater by VUV/air

以真空紫外/曝气(vacuum ultraviolet/air,VUV/air)降解模拟废水中的苯甲羟肟酸为研究对象,考察了废水p H、曝气量、污染物初始浓度及共存阴离子等因素对VUV/air降解苯甲羟肟酸效果的影响。实验结果表明:在VUV光源功率10W、苯甲羟肟酸初始浓度30mg/L、废水初始p H=4、曝气量0.6L/min、反应时间120min的条件下,VUV/air对苯甲羟肟酸模拟废水的降解效果最好,降解率为78.89%;其中共存阴离子对VUV/air降解苯甲羟肟酸的影响作用大小顺序依次为:SiO_3^(2–)>HCO_3~–>CO_3^(2–)>SO_4^(2–)>Cl~–。通过对VUV/air降解苯甲羟肟酸的机理分析研究发现,VUV/air降解苯甲羟肟酸的过程中起主要作用的是直接光降解和真空紫外产生的羟基自由基氧化分解。VUV/air降解废水中苯甲羟肟酸的行为符合一级动力学方程ln(C_t/C_0)=-kt。

Effects of pH,aeration rate,initial concentration of pollutant and coexisting anions on thedegradation of benzohydroxamic acid in wastewater by VUV/air(vacuum ultraviolet)were studied.The experimental results showed that the best degradation rate could reach78.89%when the VUV lightpower10W,benzohydroxamic acid concentration30mg/L,wastewater pH4,aeration rate0.6L/minand the reaction time120min.Among these coexisting anions,the influence on degradation from highto low was:SiO32–>HCO3–>CO32–>SO42–>Cl–.Based on the mechanism analysis for thedegradation of benzohydroxamic acid by VUV/air,the direct photolysis and oxygenolysis of hydroxylradical produced by vacuum ultraviolet radiation played the main role in this process.The degradationresult was fitted to the first-order kinetic equation,ln(Ct/C0)=–kt.