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In this study, adsorption of a non-steroidal anti-inflammatory drug such as Diclofenac (DCF) on a commercial carbonaceous aerogel honeycomb monolith (NANOLIT®-NQ40) was ascertained. Based on, the overall design of an adsorption treatment should include a feasible regeneration process for the spent adsorbent. In this work, the adsorption/desorption process was ameliorated by coupling of electrochemical technology (anodic/cathodic polarisation). It was determined that the anodic polarisation enhanced the DCF removal and it was related with the applied voltage and the disposition of the electrodes into the bulk solution. Anodic polarisation at optimal conditions (voltage 0.9 V, electrodes gap 2.5 cm and electrolyte concentration higher than 1 mM) provoked an enhancement (around 30%) in the DCF adsorption rate. The spent aerogel regeneration method for the adsorbed or electro-adsorbed DCF was investigated and cathodic polarisation proved to be a viable regeneration alternative attaining the total regeneration of aerogel. The electro-desorption mechanism seemed to be linked to the generation of repulsive intermolecular forces in the aerogel surface. Finally, the sequential electro-adsorption/electro-desorption process was performed in successive cycles. The results confirmed the feasibility of this strategy, maintaining the efficiency with no structural changes in the monolith after several cycles being the electro-reversible adsorption of pollutants on aerogel a promising technology for the removal of pharmaceuticals from wastewater. Financiado para publicación en acceso aberto: Universidade de Vigo/CISUG Agencia Estatal de Investigación | Ref. CTM 2017-87326-R

Over the last decades, advanced oxidation processes have often been used alone, or combined with other techniques, for remediation of ground and surface water pollutants. The application of heterogeneous catalysis to electrochemical advanced oxidation processes is especially useful due to its efficiency and environmental safety. Among those processes, electro-Fenton stands out as the one in which heterogeneous catalysis has been broadly applied. Thus, this review has introduced an up-to-date collation of the current knowledge of the heterogeneous electro-Fenton process, highlighting recent advances in the use of different catalysts such as iron minerals (pyrite, magnetite or goethite), prepared catalysts by the load of metals in inorganic and organic materials, nanoparticles, and the inclusion of catalysts on the cathode. The effects of physical-chemical parameters as well as the mechanisms involved are critically assessed. Finally, although the utilization of this process to remediation of wastewater overwhelmingly outnumber other utilities, several applications have been described in the context of regeneration of adsorbent or the remediation of soils as clear examples of the feasibility of the electro-Fenton process to solve different environmental problems. Xunta de Galicia | Ref. ED431C 2017/47 Ministerio de Economía y Competitividad (España) | Ref. CTM2014-52471-R

Conventional water treatments are generally inadequate for degradation of emerging pollutants such as ionic liquids (ILs). The use of heterogeneous electro-Fenton (HEF) has attracted great interest, due to its ability to efficiently oxidize a wide range of organic pollutants operating in cycles or in continuous mode. In this study, the removal of a complex IL from the imidazolinium family (1,3-Bis(2,4,6-trimethylphenyl)imidazolinium chloride), by means of HEF using iron alginate spheres as catalyst has been investigated, resulting in significant TOC decay after 6 h. The optimization of the key process parameters (current, IL concentration and catalyst dosage) has been performed using a Box-Behnken experimental design and achieving 76.98% of TOC abatement in 2 h of treatment. Current proved to be a crucial parameter and high catalyst dosage is required to achieve the maximum removal. In addition, an insight about the availability of iron into the reactor and the evolution of several intermediates has been carried out by employing differential pulse voltammetry on screen-printed carbon electrodes. The evolution of the different voltammetric peaks confirmed the influence of iron release, and the generation of several iron complexes has permitted the comprehension of the degradation pathway, which has been validated by chromatographic techniques. Ministerio de Economía y Competitividad (España) | Ref. CTM2014-52471-R