Synthetic Boron-Doped Diamond Electrodes for Electrochemical Water Treatment

Boron-doped diamond electrodes have emerged as anodic material due to their high physical, chemical and electrochemical stability. These characteristics make it particularly interesting for electrochemical wastewater treatments and especially due to its high overpotential for the Oxygen Evolution Reaction. Diamond electrodes present the maximum efficiency in pollutant removal in water, just limited by diffusion-controlled electrochemical kinetics. Results are presented for the elimination of benzoic acid and for the electrochemical treatment of synthetic tannery wastewater. The results indicate that diamond electrodes exhibit the best performance for the removal of total phenols, COD, TOC, and colour.

Electrocatalytic Performance of SiO2-SWCNT Nanocomposites Prepared by Electroassisted Deposition

Composite materials made of porous SiO2 matrices filled with single-walled carbon nanotubes (SWCNTs) were deposited on electrodes by an electroassisted deposition method. The synthesized materials were characterized by several techniques, showing that porous silica prevents the aggregation of SWCNT on the electrodes, as could be observed by transmission electron microscopy and Raman spectroscopy. Different redox probes were employed to test their electrochemical sensing properties. The silica layer allows the permeation of the redox probes to the electrode surface and improves the electrochemical reversibility indicating an electrocatalytic effect by the incorporation of dispersed SWCNT into the silica films.

Tirant lo Blanch plurilingüe. De la traducció com a eina per estudiar millor els originals i escampar-ne el coneixement

La novel·la del cavaller valencià Joanot Martorell, Tirant lo Blanch (València, 1490; amb una segona edició a Barcelona, també incunable, 1497), és un magnífic representant de la cultura dels valencians i, en general, de la Corona d'Aragó. Aquesta novel·la és una obra mestra de la literatura medieval i del Renaixement i una aportació fonamental de la Corona d'Aragó, i, més en concret, de les Lletres Valencianes, al desenvolupament de la novel·la moderna i al cànon cultural occidentals. L'obra de Martorell ha gaudit sempre un reconegut prestigi, ja d'ençà que Miguel de Cervantes, al capítol sisé del Quixot, en digués "el mejor libro del mundo"; i és establert que el Tirant va influir en diversos dels aspectes que han contribuït a individuar el Quixot com una obra que no encaixava en el panorama dels "libros de caballería" castellans de l'època i que, tanmateix -i per això mateix- contribueixen a l'enorme valor afegit de l'obra de Cervantes. Tirant lo Blanch, a través de Tirante el Blanco, aporta un cabal fonamental per a fer possible el to i inclús l'estil polifònic i el tractament en cert punt irònic de la mimesi literària tan característic en l'obra de Cervantes gràcies al contrast entre la bogeria llibresca d'Alonso Quijano i el sentit comú de Sancho (NAVARRO 2011). Tirant-Tirante no perd mai de vista la realitat, fins i tot mor al llit, d'un mal real i humà, una angina de pit, després de dictar personalment el seu testament i després de deixar els seus assumptes arreglats. El Quixot també morirà, en un context i ambient de realitat, i no com solia produir-se la mort en els llibres de cavalleries. En definitiva, de la mateixa manera que la seua versió original, aquesta versió en espanyol constitueix una obra excepcional en el context de la literatura de tema cavalleresc en l'Edat Mitjana i poc o no res té a envejar a les obres de Chrétien de Troyes o amb la Quête du Saint Graal o la Vulgata en conjunt (MARTINES, 1995; HAUF, 1995).

Modulation of the Silica Sol–Gel Composition for the Promotion of Direct Electron Transfer to Encapsulated Cytochrome c

The direct electron transfer between indium–tin oxide electrodes (ITO) and cytochrome c encapsulated in different sol–gel silica networks was studied. Cyt c@silica modified electrodes were synthesized by a two-step encapsulation method mixing a phosphate buffer solution with dissolved cytochrome c and a silica sol prepared by the alcohol-free sol–gel route. These modified electrodes were characterized by cyclic voltammetry, UV–vis spectroscopy, and in situ UV–vis spectroelectrochemistry. The electrochemical response of encapsulated protein is influenced by the terminal groups of the silica pores. Cyt c does not present electrochemical response in conventional silica (hydroxyl terminated) or phenyl terminated silica. Direct electron transfer to encapsulated cytochrome c and ITO electrodes only takes place when the protein is encapsulated in methyl modified silica networks.

Enhancement of the Electrochemical Performance of SWCNT dispersed in a Silica Sol-gel Matrix by Reactive Insertion of a Conducting Polymer

The electroassisted encapsulation of Single-Walled Carbon Nanotubes was performed into silica matrices (SWCNT@SiO2). This material was used as the host for the potentiostatic growth of polyaniline (PANI) to yield a hybrid nanocomposite electrode, which was then characterized by both electrochemical and imaging techniques. The electrochemical properties of the SWCNT@SiO2-PANI composite material were tested against inorganic (Fe3+/Fe2+) and organic (dopamine) redox probes. It was observed that the electron transfer constants for the electrochemical reactions increased significantly when a dispersion of either SWCNT or PANI was carried out inside of the SiO2 matrix. However, the best results were obtained when polyaniline was grown through the pores of the SWCNT@SiO2 material. The enhanced reversibility of the redox reactions was ascribed to the synergy between the two electrocatalytic components (SWCNTs and PANI) of the composite material.

Electrochemical Behaviour of PSS-Functionalized Silica Films Prepared by Electroassisted Deposition of Sol–Gel Precursors

Porous, electrically insulating SiO2 layers containing polystyrene sulfonate (PSS) were deposited on glassy carbon electrodes by an electrochemically assisted deposition method. The obtained material was characterized by microscopic, spectroscopic and thermal techniques. Silica-PSS films modify the electrochemical response of the glassy carbon electrodes against selected redox probes. Positively charged species show reduced diffusivities across the SiO2-PSS pores, which resulted in a concentration ratio higher than 1 for these species. The opposite behaviour was found for negatively charged redox probes. These observations can be interpreted in terms of the different affinity of the GC/SiO2-PSS-modified electrode for the electroactive species, as a consequence of the negatively charged porous silica.

Cabecera cuadrada renacentista con bóveda pseudo-esférica cruzada en la iglesia Santiago de Orihuela (Alicante)

Jerónimo Quijano fue uno de los ilustres arquitectos destacados del Renacimiento pleno en España. Su obra, la iglesia de Santiago en Orihuela -Alicante- posee una Capilla Mayor renacentista, de carácter funerario, de planta central y adosada a una nave gótica. Destaca su bóveda superior de 4 pares de arcos entrecruzados y revirados. Al ser dobles se reduce la superficie central de plementería y se gana en resistencia. Es de complicada geometría esférica y cuadrada a la vez: bóveda pseudo-vaída (esférica solo hasta los arcos exteriores) y plementería lateral adaptándose a la planta cuadrada. Supone la fusión de la antigüedad clásica con la tradición hispanomusulmana. Como referencia, se estudia sucintamente la Capilla Benavides en Baeza - Jaén-, obra de Andrés de Vandelvira e incluida en el tratado de arquitectura de su hijo Alonso, la cual plantea un gran espacio cuadrado cubierto por una bóveda vaída y reforzada por 4 arcos entrecruzados.