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a b s t r a c tNovel magnetic carbon xerogels consisting of interconnected carbon microspheres with iron and/or cobalt microparticles embedded in their structure were developed by a simple route. As inferred from the characterization data, materials with distinctive properties may be directly obtained upon inclusion of iron and/or cobalt precursors during the sol-gel polymerization of resorcinol and formaldehyde, followed by thermal annealing. The unique properties of these magnetic carbon xerogels were explored in the catalytic wet peroxide oxidation (CWPO) of an antimicrobial agent typically found throughout the urban water cycle -sulfamethoxazole (SMX).A clear synergistic effect arises from the inclusion of cobalt and iron in carbon xerogels (CX/CoFe), the resulting magnetic material revealing a better performance in the CWPO of SMX at the ppb level (500 g L −1 ) when compared to that of monometallic carbon xerogels containing only iron or cobalt. This effect was ascribed to the increased accessibility of highly active iron species promoted by the simultaneous incorporation of cobalt.The performance of the CWPO process in the presence of CX/CoFe was also evaluated in environmentally relevant water matrices, namely in drinking water and secondary treated wastewater, considered in addition to ultrapure water. It was found that the performance decreases when applied to more complex water and wastewater samples. Nevertheless, the ability of the CWPO technology for the elimination of SMX in secondary treated wastewater was unequivocally shown, with 96.8% of its initial content being removed after 6 h of reaction in the presence of CX/CoFe, at atmospheric pressure, room temperature (T = 25 • C), pH = 3, [H 2 O 2 ] 0 = 500 mg L −1 and catalyst load = 80 mg L −1 . A similar performance (97.8% SMX removal) is obtained in 30 min when the reaction temperature is slightly increased up to 60 • C in an ultrapure water matrix. Synthetic water containing humic acid, bicarbonate, sulphate or chloride, was also tested. The results suggest the scavenging effect of the different anions considered, as well as the negative impact of dissolved organic matter typically found in secondary treated wastewater, as simulated by the presence of humic acid.An in-situ magnetic separation procedure was applied for catalyst recovery and re-use during reusability cycles performed to mimic real-scale applications. CWPO runs performed with increased SMX 171 concentration (10 mg L −1 ), under a water treatment process intensification approach, allowed to evaluate the mineralization levels obtained, the antimicrobial activity of the treated water, and to propose a degradation mechanism for the CWPO of SMX.

The present study deals with the inactivation of Escherichia coli and Klebsiella pneumoniae in water by means of heterogeneous photocatalysis under simulated solar irradiation. For this purpose, novel Mn-, Co-and Mn/Co-doped TiO 2 catalysts were prepared. A straightforward, simple and inexpensive process has been developed based on a co-precipitation method for the synthesis of metal-doped catalysts, which were subsequently assessed in terms of their disinfection efficiency. The effect of various operating conditions, such as metal dopant (Mn-, Co-and Mn/Co), dopant concentration (0.02-1 wt%), catalyst concentration (25-250 mg/L), bacterial concentration (10 2-10 8 CFU/mL), treatment time (up to 60 min), toxic effects on bacteria and photon flux (4.93-5.8×10-7 einstein/(L.s)), was examined under simulated solar irradiation. Metal-doped TiO 2 samples were prepared reproducibly and doping shifted the optical absorption edge to the visible region. Their activity was superior to the respective of commercially available P25 titania. The reference strains of E. coli and K. pneumoniae proved to be readily inactivated during photocatalytic treatment of aqueous samples, since disinfection occurred rapidly (i.e. after only 10 min of irradiation) with the dopant concentration affecting the overall process to a certain extent. Disinfection follows a pseudofirst order kinetic rate in terms of both bacteria removal. Inactivation of the bacteria is attributed to the oxidative degradation of their cells and increase of their cell permeability and not to the potential toxicity of the metal-doped semiconductors, which did not exhibit any bactericidal properties. It has been shown that the improved activity of the Mn-, Co-, and binary Mn/Co doped TiO 2 is accredited to the fact that they can be activated in the visible part of the spectrum, in the absence of UV light (i.e. >420 nm).