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Biomass as key to water reclamation: sugar-derived carbons allow high adsorption capacities for the removal of pharmaceuticals from water.

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The selective oxidation of styrene under heterogeneous catalyzed conditions delivers environmentally friendly paths for the production of benzaldehyde, an important intermediate for the synthesis of several products. The present review explores heterogeneous catalysts for styrene oxidation using a variety of metal catalysts over the last decade. The use of several classes of supports is discussed, including metal–organic frameworks, zeolites, carbon materials and silicas, among others. The studied catalytic systems propose as most used oxidants tert-butyl hydroperoxide, and hydrogen peroxide and mild reaction conditions. The reaction mechanism proceeds through the generation of an intermediate reactive metal–oxygen species by catalyst-oxidant interactions. Overall, most of the studies highlight the synergetic effects among the metal and support for the activity and selectivity enhancement.

The photocatalytic performance of titania/Cu-carbon composites was investigated towards phenol degradation under visible light. The approach consisted on the incorporation of the transition metal on the carbon component of the hybrid composite via impregnation of the carbon precursor with a metal salt followed by activation. Data showed a homogeneous dispersion of copper particles within the carbonaceous matrix, predominantly as copper (II) species. The synthesized carbons displayed a well developed nanoporous texture, although comparatively the impregnation of copper caused a marked inhibition of the textural development of the carbon precursor. The phenol photooxidation tests carried out on 1:1 titania/carbon composites showed the outstanding role of copper under visible light, with an increased efficiency in terms of phenol conversion, mineralization degree and degradation rate. This is important, since similar overall conversions were obtained with half of the amount of the photoactive semiconductor (1:1 composites). The beneficial effect of copper loading was also observed in the marked regioselectivity towards the preferential formation of catechol. Furthermore, the copper-loaded photocatalyst was found to be stable with no lixiviation or photorreduction of the copper species after illumination.