水质对UV/H_2O_2降解2,4-二氯酚的影响

研究了UV/H2O2工艺对2,4-二氯酚(2,4-DCP)的去除效果和水中阴离子、腐殖酸对该工艺降解2,4-DCP的影响。结果表明:UV/H2O2工艺可以有效的去除水中2,4-DCP,光降解过程符合一级反应动力学模型;在H2O2投加量为8mg/L,1个30W低压汞灯照射下,2,4-DCP在蒸馏水和自来水中光降解速率常数分别为0.0232/min和0.0162/min;NO3-、Cl-、HCO3-对2,4-DCP光降解有抑制作用;当3种离子浓度为0.5mmol/L、10mmol/L、20mmol/L时,对2,4-DCP光降解的抑制程度为HCO3->NO3->Cl-;随着离子浓度增大,抑制作用增强;自来水中的光降解速率常数低于蒸馏水中的光降解速率常数是由于水中多种离子影响的结果;腐殖酸在低浓度时,促进光降解反应的进行,在高浓度时,2,4-DCP的光降解氧化受到抑制。

Effect and Mechanism of Anions and Humic Acid in Aqueous Solution on Degradation of 2,4 -DCP by UV/H2O2 Combination Process

The effect of UV/H2O2 process as well as anions and humic acid in aqueous solution on degradation of 2,4-DCP was studied.Results showed that UV/H2O2 process could remove 2,4-DCP effectively,with the process of photodegradation following the first order reaction kinetics model.Under the condition of H2O2 concentration of 8mg/L and irradiation of 30W low pressure mercury vapor discharge lamp,the photodegradation rate constant of 2,4-DCP in distilled water and tap water was 0.0232min-1 and 0.0162min-1 respectively.NO3-,Cl-and HCO3-has inhibitory action on photodegradation of 2,4-DCP.When anion concentration was 0.5mmol/L,10 mmol/L and 20 mmol/L,the inhibitory action order was HCO3-,NO3-and Cl-.The higher anions concentration was,the stronger inhibitory action.It was anions synthetic effect that caused photodegradation rate constant of 2,4-DCP in tap water lower than distilled water.Low humic acid concentration accelerated 2,4-DCP photodegradation rate while high humic acid concentration restrained photodegradation.