Photodegradation of powerful five estrogens collected from waste water treatment plant over visible-light-driven Au/TiO₂ photocatalyst

In wastewater effluents, the removal of endocrine-disrupting chemicals (EDCs) through the traditional remediation approaches is insufficient, and the existence of EDCs may cause human health risks and potential ecological even at low concentrations. In this contribution, the kinetics and efficiencies of photodegradation for individual estrogens and multicomponent estrogens solution of diethylbestrol (DES), estrone (E1), 17 β- estradiol (E2), 17-α Ethinyestradiol, (EE2) and Estoril (E3) were performed over Au/TiO ₂ photocatalyst through UV and visible light exposure. The photodegradation efficiency for single component estrogen of DES, E1, E2, E3 and EE2 over 0.1%Au/TiO ₂ photocatalyst under UV illumination was determined to 99.5%, 100%, 100%, 97.2% and 100% within 30 min. The estrogens in the multicomponent mixture of E1, E2 and EE2 were removed, reaching about 97.78, 88.60 and 92.10%, respectively, within 40 min of UV illumination, and they were almost completed within 75 min under visible light illumination. The degradation rate constants (k) values for single component experiments of estrogens, follows the trend of EE2 (0.352 min ⁻¹) > E1 (0.235 min ⁻¹) > DES (0.115 min ⁻¹) > E2 (0.111 min ⁻¹) > E3 (0.069 min ⁻¹). In addition, k values under UV illumination for target estrogens in multicomponent follows the sequence DES (0.179 min ⁻¹) > E1(0.12 min ⁻¹) > E3 (0.061 min ⁻¹) > E2(00.054 min ⁻¹). However, under visible light illumination the k values are followed the orders E3 (0.097 min ⁻¹) > DES (0.08 min ⁻¹) > E1(0.07 min ⁻¹) > E2(0.066 min ⁻¹). The obtained k values of estrogens treated with 0.1%Au/TiO ₂ photocatalyst in the present work through UV and visible light exposure was greater than that reported in the previously published work. Overall, 0.1%Au/TiO ₂ photocatalyst demonstrated superior performance for photodegradation of DES, E1, E2, E2 and EE2 in synthetic solution and wastewater effluent collected from Kuwait's Kubd Waste Water Treatment Plant The photodegradation mechanism of estrogens over Au/TiO ₂ photocatalyst discussed depends on the basis of the attack of ^⋅OH.