Effect and Mechanism of Anions and Humic Acid in Aqueous Solution on Degradation of 2,4-DCP by UV/H_2O_2 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.