臭氧氧化降解水中苯酚的效能及动力学

Degradation Efficiency and Kinetics of Ozonation of Phenol in Water

在常温常压下对臭氧氧化降解废水中苯酚的效能、反应动力学及其影响因素进行了详细研究。结果表明,在臭氧投加量为8.50mg/min、苯酚初始质量浓度为100mg/L、初始pH值为11和反应时间为40min时,臭氧对苯酚的降解效果最好,苯酚从100mg/L降至0.35mg/L,降解率达到99.65%;且自来水本底比去离子水本底更有利于水中苯酚的臭氧氧化降解。在上述实验条件下,臭氧对苯酚的降解遵循表观拟一级反应动力学,其相关系数R2=0.9929,表观反应速率常数kA=1.06×10-3 s-1。实验还发现,苯酚降解的表观反应速率常数随着臭氧投加量(4.25～8.50mg/min)的增加而增大,在臭氧投加量为8.50mg/min时达到最大值1.06×10-3 s-1;随着苯酚初始质量浓度(100～250mg/L)的增大,表观反应速率常数从1.06×10-3 s-1下降到0.39×10-3 s-1;随着溶液初始pH值(5～11)的升高,表观反应速率常数从0.22×10-3 s-1增加到1.06×10-3 s-1。在某种程度上证明了表观反应速率常数分别与臭氧投加量和溶液初始pH值成正相关性,与苯酚初始质量浓度成负相关性。

The degradation efficiency,kinetics and the effect factors of the phenol in wastewater by ozonation process were investigated.The results indicated that the ozonation process was most effective in the degradation of the phenol at the ozone dosage of 8.50 mg/min,initial phenol concentration of 100 mg/L,initial pH value of 11,and reaction time of 40 min,under which the degradation rate of phenol was 99.65%,and the phenol mass concentration declined to 0.35 mg/L.And the degradation efficiency for phenol in tap water was higher than that in distilled water.Under the above conditions of this experiment,the degradation of the phenol followed the apparent pesudo-first-order kinetic model with its correlation coefficient R2 of 0.9991,and the rate constants k was 1.01×10^-3 s^-1.However,with the increase of ozone dosage（4.25-8.50 mg/min）,the apparent rate constant of phenol degradation reached the climax of 1.06×10^-3 s^-1 at the ozone dosage of 8.50 mg/min,and dropped from 1.06×10^-3 s^-1 to 0.39×10^-3 s^-1 with the increase of the initial concentration of phenol（100-250 mg/L）,and expended from 0.22×10^-3 s^-1 to 1.06×10^-3 s^-1 with the enlarging of pH value（5-11）.The experiments also proved that the apparent rate constants of the phenol degradation in wastewater by ozonation had positive relativity with the ozone dosage and initial pH value of aqueous solution,but had negative relativity to initial phenol mass concentration.