UV及UV/US降解对二氯苯水溶液的研究

Photodegradation and photosonodegradation of p-dichlorobenzen in aqueous solution

使用紫外光(UV)和超声波(US)降解水溶液中的对二氯苯(p-DCB)。考察了p-DCB初始浓度,初始pH、腐殖酸和H2O2的存在对p-DCB光解的影响。结果表明,较低的初始浓度或弱酸性pH有利于p-DCB降解。溶液中存在20 mg/L的腐殖酸可使p-DCB的反应速率常数提高32.6%。加入氧化剂H2O2可以显著提高p-DCB的降解率,在[p-DCB]0=0.1 mmol/L,[H2O2]0=0.1 mmol/L,pH0=5.8,反应180 min条件下,p-DCB的降解率为95.5%。超声波对p-DCB的降解速率(14.6×10-3/min)大约是紫外光(4.3×10-3/min)的3.4倍,紫外光-超声波耦合时的降解速率(20.6×10-3/min)大于两者单独降解速率的加合。在各种实验条件下,p-DCB的降解均遵循表观一级动力学。

The degradation of p-DCB in aqueous solution was studied by ultraviolet and ultrasonic irradiation.The effect of initial p-DCB concentration,initial pH,the presence of humic acid and H2O2 on the p-DCB photolysis was investigated.The results indicated that,lower initial concentration or weak acid condition were favorable for p-DCB degradation.The degradation rate increased by 32.6% with 20 mg/L humic aid.The degradation of p-DCB was significantly improved by adding oxidant H2O2,and the degradation efficiency was 95.5% at 0=0.1 mmol/L,0=0.1 mmol/L,pH0=5.8 after 180 min radiation.The rate constant of sonodegradation（14.6×10-3/min） was 4.3 times that of the photodegradation（4.3×10-3/min）,and the rate constant of photosonodegradation（20.6×10-3/min） was greater than the sum of those for the two individual processes.Under various experimental conditions,the degradation of p-DCB followed the apparent first order kinetics.