Efficient removal of cytotoxic drugs from wastewater by single-stage combined photocatalysis-algae treatment process

In this study, the efficiency of a single-stage combined photocatalysis-algae treatment process in the removal of the anticancer drug, flutamide (FLU), from aqueous solution has been evaluated. The removal abilities of the individual blue-green alga (Anabaena sp.), nano-sized MoS₂ photocatalyst under visible light irradiation, and combined photocatalysis-algal treatment process were investigated. Using response surface optimization technique, 85.1% of the FLU removal was achieved at the optimum conditions of pH 7.0, nanophotocatalyst dose of 15.23 mg and 12.12 mL of the alga in 30 min. Compared to the individual biological and chemical treatment methods, a higher FLU removal efficiency was obtained at a shorter reaction time by using the combined treatment system. Kinetics study showed that FLU removal by the algal treatment, photocatalysis, and the combined processes followed the modified Freundlich, pseudo-first-order, and nonlinear sigmoidal kinetic models, respectively. The results indicate that a synergistic effect appears when algal treatment process and photocatalysis are performed simultaneously. The novel combined system is a low-cost and efficient microalgae-based technology for the removal of cytotoxic compounds from wastewaters.