Solar-driven photodegradation of ciprofloxacin and E. coli growth inhibition using a Tm3+ upconverting nanoparticle-based polymer composite

Solar-driven photocatalysis is of great interest in terms of a sustainable use of energy and its application in wastewater treatment. The UV light-driven photogeneration of H2O2 by solar irradiation is an advanced strategy for the treatment of bacteria and recalcitrant pollutants in wastewater, but suffers from low efficiencies. In this work, a solar-driven multifunctional nanocomposite consisting of Tm3+ upconverting nanoparticles, poly(vinyl alcohol), poly(acrylic acid) and hydroxylated sulfonated poly(ether ether ketone) was prepared. The components were crosslinked via a heating treatment at 170 degrees C, resulting in a non-leaching porous material. This nano-composite exhibited excellent adsorption ability (89 % in 150 min) toward a 100 mg/L ciprofloxacin aqueous solution and proved to photodegrade it (50 %) upon 4 h artificial solar irradiation, exploiting photon upcon-version processes. Moreover, an 80 % bactericidal effect against E. coli was registered upon sunlight irradiation. Altogether, these results suggest the feasibility of a solar-driven wastewater treatment based on upconverting nanoparticles.