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Sunscreen agents are chemical compounds widely used nowadays for skin protection from UV sunlight. Recently, their ubiquitous occurrence in aquatic systems has been evidenced, which poses a high risk for the environment and human health as they are associated with endocrine disrupting activity, reproductive toxicity, and genotoxicity. In this work, the feasibility of an economically and environmentally friendly catalytic system based on the thermally modified natural magnetite and hydrogen peroxide (Fe 3 O 4 -R400/H 2 O 2), has been evaluated for the degradation of two representative sunscreen agents: benzophenone-3 (BP-3) and 4-aminobenzoic acid (PABA) in wastewater. The experiments were conducted under circumneutral pH (pH 0 = 5), with temperature control (25 °C). Both compounds (500 μg L−1) were successfully removed from water by using a relatively low catalyst concentration (0.5 g L−1) and the theoretical stoichiometric H 2 O 2 dose for their complete oxidation (∼2.3 mg L−1). Afterwards, a complete operating condition study was performed with BP-3, given its predominant occurrence in fresh waters, analysing the influence of H 2 O 2 dose (1.2–4.6 mg L−1), catalyst concentration (0.1–0.5 g L−1), and temperature (25–45 °C). From the evolution of the identified by-products, a reaction pathway was proposed according to which oxidation of BP-3 gives rise to several aromatic intermediates, which finally evolve to short-chain organic acids. The generation of such aromatic by-products led to a considerably ecotoxicity increase in the initial stages of the reaction, but non-toxic effluents were ultimately achieved. Notably, the mineralization yield reached was above 60%. As a proof of concept, the feasibility of the system was finally demonstrated in real water matrices (WWTP effluent and surface water). [Display omitted] • The Fe 3 O 4 -R400/H 2 O 2 system was effective for the removal of sunscreen agents. • The pollutants were highly mineralized (∼60%), yielding short-chain acids. • A reaction pathway for BP-3 oxidation was proposed. • Non-toxic effluents were obtained despite a slight initial ecotoxicity increase. • The feasibility of the process was demonstrated in different water matrices. [ABSTRACT FROM AUTHOR]

This work aims to develop highly stable iron oxide foams for the continuous Catalytic Wet Peroxide Oxidation (CWPO) of micropollutants in a structured fixed-bed reactor. Homogeneity and adhesion of the active phase were achieved by adjusting the preparation methodology. Three structured catalysts based on Al 2 O 3 , SiC and ZrO 2 foams were obtained with Fe content of 2.5%, 2.1% and 0.90% wt., respectively. The catalytic foams were tested in the CWPO of a mixture of three pharmaceuticals (metronidazole (MNZ), sulfamethoxazole (SMX) and carbamazepine (CBZ)), with a concentration of 100 µg L−1 each. The catalysts resulted active and stable up to 200 h of CWPO carried out at ambient conditions, with the exception of Fe/ZrO 2 , which showed a progressive deactivation due to the iron leaching from the solid. An increase in space time led to an enhanced performance achieving remarkable conversion levels of 73%, 83% and 90% for MNZ, SMX and CBZ, respectively. The effect of H 2 O 2 dose was also evaluated revealing the development of competing side reactions for supra - stoichiometric dosages. Moreover, the scavenging effect of the water matrix was assessed operating in presence of humic acid as representative natural organic matter (NOM). In this case, the conversion levels for SMX and CBZ resulted alike to the ones obtained for ultrapure water and only a slight decrease in MNZ removal rate was detected. After 400 h of usage at different steady-state conditions, the outstanding catalytic performance of Fe/Al 2 O 3 and Fe/SiC was sustained in the long-term operation. [Display omitted] • Innovative iron oxide foams based on Al 2 O 3 , SiC and ZrO 2 were developed. • The structured catalysts were tested in the continuous flow CWPO of persistent micropollutants. • Fe/Al 2 O 3 and Fe/SiC catalytic foams showed an outstanding activity and stability for 400 h. • The H 2 O 2 dose revealed competing reactions for supra-stoichiometric doses. • The versatility of the system was demonstrated in the presence of NOM. [ABSTRACT FROM AUTHOR]