[Effect of water quality on degradation of 17alpha-ethynyestradiol (EE2) by UV/H2O2 combination process]

Effect of pH, HA and anions HCO3-, NO3-, CO3(2-), Cl- and SO4(2-) in aqueous solution on the photodegradation of 17alpha-ethynyestradiol (EE2) was studied by using a batch photo-reactor. The results show that 17alpha-ethynyestradiol (EE2) could be removed effectively by the UV/H2O2 process. The rate of photodegradation in aqueous solution follows first-order kinetics. When H2O2 was dosed as 5 mg/L, irradiated by a 14W low pressure mercury vapor discharge lamp, the first-order photodegradation rate constant of EE2 in distilled water and tap water were 0.0630 min(-1) and 0.1324 min(-1) respectively. HA, HCO3-, NO3-, Cl- and SO4(2-) have inhibitory action on EE2 photodegradation. When their concentrations at 5 mmol/L, their inhibitory action: HCO3- > SO4(2-) > Cl- > NO3-. HCO3- induced photodegradation rate constant of EE2 reduced by half, It was anions synthesize effect that caused photodegradation rate constant of EE2 in tap water lower than distilled water.