Degradation of Hydroxychloroquine from Aqueous Solutions Under Fenton-Assisted Electron Beam Treatment

Challenges in the treatment and removal of recalcitrant emerging organic pollutants in wastewater prompt the development of advanced oxidative processes (AOPs). Hydroxyl radicals are non-specific and capable of reacting with a diverse range of pollutants of emerging concern. In this study, hydroxychloroquine (HCQ) was removed from aqueous solutions with removal efficiencies between 80 and 90%. The presence of H2O2, humic acid, and other inorganic ions negatively influenced the degradation efficiency. However, the presence of S2O82− was found to increase the removal efficiency, which was attributed to the formation of SO4•− in addition to •OH radicals. Additionally, Fenton-assisted electron beam treatment showed an improved removal of 2.88 × 10−4 M of HCQ with an average improvement of ≈10% at doses between 0.5 to 2.0 kGy in addition to the total organic carbon and chemical oxygen demand reduction. The H2O2 concentration and molar ratio of H2O2: Fe2+ influenced the removal capacity of the Fenton-assisted electron beam process. A degradation mechanism for HCQ has been proposed based on the reactions of •OH radicals and eaq−.