[Effects and mechanisms of inorganic anions in water on degradation of LAS by UV/H2 O2 combination process].

Experiments are carried out to study the effects and mechanisms of inorganic anions in water on the degradation of linear alkyl benzene sulfonate (LAS) in UV/H2 O2 process. The results show that UV/H2 O2 process could remove LAS effectively, and the rate of photodegradation follows first-order reaction kinetics model. Under the condition that H2 O2 concentration was 8 mg x L(-1) and a 14 W low pressure mercury vapor discharge lamp irradiated samples, the first-order photodegradation rate constant of LAS in distilled water and tap water were 0.018 0 min(-1) and 0.012 2 min(-1) respectively. NO3-, Cl-, SO4(2-) and HCO3- have inhibitory action on LAS photodegradation. The higher inorganic anions concentration was, the stronger inhibitory action. When their concentrations were 5, 10 and 15 mmol x L(-1) respectively, their inhibitory action order was HCO3- > NO3- > Cl- > SO4(2-) all the time. It was anions synthetical effect that caused photodegradation rate constant of LAS in tap water lower than distilled water.