Pilot-scale study on photodegradation of benzophenone-3 and benzophenone-8 ultraviolet filters enriched synthetic effluent

Abstract

Ultraviolet (UV) filters are the significant ingredients of sunscreens, cosmetics, and other personal care products. They are used to guard human body against harmful UV radiations present in sunlight. In recent years, due to their excessive use, high UV filters concentrations have been detected in swimming pools. The present study was aimed to photodegrade the two most commonly used UV filters, namely benzophenone-3 (BP-3) and benzophenone-8 (BP-8) using pilot-scale advanced oxidation process (AOP) treatment. The photodegradation of selected UV filters was optimised under various oxidant systems viz. hydrogen peroxide (H2O2), potassium peroxomonosulphate (PMS), and potassium peroxodisulphate (PDS). In the absence of oxidant, the photodegradation rate of BP-3(58.25%) was higher than BP-8 (48.31%). The generation of SO4.- and.OH radicals enhanced the degradation of UV filters. Similar degradation trend (UVC < UVC/PMS < UVC/H2O2 < UVC/PDS) was observed for both BP-3 and BP-8 in presence of oxidants. However, on comparing the efficiency, the photodegradation of BP-3 was better in most of the UVC/oxidant systems. Generation of degradation by-products viz. bezonic acid, 2,4-dimethyl benzaldehyde, 2-methylphenyl benzoate, and benzyl alcohol was confirmed through mass spectroscopic (MS) analysis. Degradation mechanism of UV filters was proposed and overall process cost was estimated. The findings of the current study could be a baseline for treating swimming pools water.