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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.

This work reports for the first time the removal of 17α-ethynylestradiol (EE2), a synthetic estrogen hormone, from secondary treated effluents by electrochemical oxidation. Experiments were conducted in a single compartment reactor comprising a boron-doped diamond (BDD) anode and a zirconium cathode. EE2, in the range 100-800 µg L −1 , was spiked in the postchlorination effluent of a municipal treatment plant and oxidized at 0.9-2.6 mA cm −2 current density. Complete degradation of 100 µg L −1 EE2 was achieved in 7 min at 2.1 mA cm −2 and inherent conditions, while the addition of 0.1 mol L −1 NaCl achieved removal in just a few seconds. The process was then tested in the pre-chlorination effluent at 2.1 mA cm −2 and inherent conditions; complete E. coli killing and EE2 removal occurred in just 1.5 and 3.5 min, respectively, while overall estrogenicity (assessed by the YES assay) and residual organic matter (in terms of chemical oxygen demand (COD)) decreased by 50% and 85% after 30 min, respectively. These results clearly show the potential of BBD electrochemical oxidation to serve as an efficient tertiary wastewater treatment.

a b s t r a c tThe efficiency of heterogeneous photocatalysis to degrade 17␣-ethynylestradiol (EE2), a synthetic estrogen hormone, in environmentally relevant samples was investigated. In most cases, UV-A radiation at a photon flux of 2.81 × 10 −4 einstein/min was provided by a 9 W lamp and experiments were conducted at various concentrations of Aeroxide P25 TiO 2 (50-1000 mg/L), EE2 concentrations (50-900 g/L) and water matrices (from ultrapure water to secondary treated wastewater). Some runs were performed at photon fluxes between 6.4 × 10 −7 and 3.7 × 10 −4 einstein/min to study the effect of intensity on degradation. Changes in estrogen concentration were followed by high performance liquid chromatography. EE2 degradation, which follows first order kinetics, increases with (i) increasing catalyst loading up to a threshold value beyond which it remains unaffected; (ii) increasing photon flux and (iii) decreasing matrix complexity, i.e. the organic and inorganic constituents of wastewater retard degradation. This may be overcome coupling photocatalysis with ultrasound radiation at 80 kHz and 41 W/L power density; the combined sonophotocatalytic process acts synergistically toward EE2 degradation. Several transformation products were identified by means of UPLC-MS/MS and a reaction network for the photocatalytic degradation of EE2 is suggested.An artificial neural network comprising five input variables (reaction time, TiO 2 and EE2 concentration, organic content and conductivity of the water matrix), thirteen neurons and an output variable (EE2 conversion) was optimized, tested and validated for EE2 degradation. The network, based on tangent sigmoid and linear transfer functions for the hidden and input/output layers, respectively, and the Levenberg-Marquardt back propagation training algorithm, can successfully predict EE2 degradation.

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