Enhanced removal of bisphenols using immobilized TiO₂ in photocatalytically assisted hydrodynamic cavitation

Bisphenols are widespread in the environment and can cause harm to aquatic and terrestrial life by acting as an endocrine disruptor, affecting reproduction, growth, and development. Hydrodynamic cavitation and photocatalysis can both be used to remove bisphenols from aquatic bodies, yet the reports on the combination of the two in a single system are scarce. Herein, we studied the removal of five bisphenols from tap water (TW) and real wastewater (WW) effluent at two environmentally relevant concentration levels, 200 ng/L and 1000 ng/L, by means of hydrodynamic cavitation, both independently and in combination with photocatalysis, using a TiO₂-SiO₂ composite catalyst immobilized on Al₂O₃ monoliths. For tap water, inside the short treatment times (15 min or 30 min) the efficiency of removal reached up to 100% for tetramethyl bisphenol F (TMBPF) while only 15% for bisphenol S (BPS). Interestingly, the average total amount of BPAs removed across all treatment combinations was almost the same in case of TW (58.5 ng) and WW (60.4 ng). The current study shows an important advancement in the practical applicability of the two methods for treating polluted water bodies which is applicable to the upcoming implementation of the quaternary treatment in WW treatment plants.