2,221 research outputs found
Who pays the taxes?
The European Union is legally entitled to the revenue from (1) agricultural and sugar levies, (2) customs duties, (3) a 1 percent rate on each Member States' value added tax base, and (4) a resource on the basis of GNP. Currently, the Union is actively involved in the search for a fifth own revenue source. Therefore, the European Commission (DG XIX) has invited the authors to trace 'who pays the taxes'. As requested, our report gives a general account of methods to investigate impacts of taxation. More specifically, we have estimated the incidence of national tax systems (Germany, the Netherlands, Spain and the United Kingdom), and the incidence of present own resources and prospective new (tax) resources of the European Union. Up till now, such information was not (readily) available.tax incidence in the European Union, prospective new EU tax resources
Who pays the taxes?
The European Union is legally entitled to the revenue from (1) agricultural and sugar levies, (2) customs duties, (3) a 1 percent rate on each Member States' value added tax base, and (4) a resource on the basis of GNP. Currently, the Union is actively involved in the search for a fifth own revenue source. Therefore, the European Commission (DG XIX) has invited the authors to trace 'who pays the taxes'. As requested, our report gives a general account of methods to investigate impacts of taxation. More specifically, we have estimated the incidence of national tax systems (Germany, the Netherlands, Spain and the United Kingdom), and the incidence of present own resources and prospective new (tax) resources of the European Union. Up till now, such information was not (readily) available.tax incidence in the European Union, prospective new EU tax resources
The distribution of effective tax burdens in four EU countries
National policymakers are increasingly aware that their tax policy options are constrained by international tax competition. Important features of national tax systems - notably the tax mix, tax rates and rules which define the tax base - will influence decisions of firms and individuals regarding the location and (re)structuring of economic activities. The aim of the present paper is twofold: Firstly, we detail the tax mix of four member states of the European Union (Germany, The Netherlands, Spain and United Kingdom). Secondly, the paper aims to trace the distribution of the tax burden over rich and poor households in these four countries. Although tax mix and tax rates differ considerably among the four countries included in the study, the distribution of tax burdens proves to be amazingly similar.Distribution of tax burden, European Union; tax mix of Germany, the Netherlands, Spain and United Kingdom
The nature of the electro-catalytic response of mixed metal oxides: Pt- and Ru-doped SnO2 anodes
"This is the peer reviewed version of the following article: The nature of the electro-catalytic response of mixed metal oxides: Pt- and Ru-doped SnO2 anodes, which has been published in final form at https://doi.org/10.1002/celc.201801632. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving."[EN] The catalytic behavior of metal oxides for oxidative reactions is generally classified into active or non-active, depending on whether surface redox species participate or not. In the case of mixed metal oxides, however, this simplified scenario may be more complex. Non-active oxides containing electroactive metal species, like Pt- and/or Ru-doped SnO2 electrodes, are promising anode materials for the electrochemical treatment of waste-waters. This work analyzes the effect of Pt and Ru species on the nature of the electro-oxidative catalytic response of Ti/SnO2 anodes. For this purpose, the electro-oxidation of phenol and the competing oxygen evolution reaction (OER) in NaOH have been chosen as model reactions. The different electrodes and reactions were characterized by cyclic voltammetry, electro- chemical impedance spectroscopy, and Tafel measurements. The obtained results reveal that both Pt and Ru introduce solid-state redox processes and catalyze the OER and the phenol oxidation onto Ti/SnO2-based electrodes. Nevertheless, the dopants induce quite different active behaviors in the mixed oxides. Pt practically does not affect the OER mechanism, but enhances its kinetics, so its electrocatalytic activity is associated with a specific adsorption of hydroxyl anions or phenolate on Pt sites, without participation of the irreversible Pt/PtOx couple (i.e. a "non-redox-active" behavior). On the contrary, Ru species involve various and highly reversible redox processes that accelerate and modify the rate-determining step of the OER, and that actively mediate in the phenol oxidation.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-201420012) is gratefully acknowledged.Berenguer Betrián, R.; Quijada, C.; Morallón, E. (2019). The nature of the electro-catalytic response of mixed metal oxides: Pt- and Ru-doped SnO2 anodes. ChemElectroChem. 6(4):1057-1068. https://doi.org/10.1002/celc.201801632S1057106864K. Rajeshwar J. G. Ibanez (Eds.) in Environmental Electrochemistry: Fundamentals and Applications in Pollution Abatement Academic Press Inc. San Diego 1997.Martínez-Huitle, C. A., & Ferro, S. (2006). Electrochemical oxidation of organic pollutants for the wastewater treatment: direct and indirect processes. Chem. Soc. Rev., 35(12), 1324-1340. doi:10.1039/b517632hBrillas, E., & Martínez-Huitle, C. A. (2015). Decontamination of wastewaters containing synthetic organic dyes by electrochemical methods. An updated review. Applied Catalysis B: Environmental, 166-167, 603-643. doi:10.1016/j.apcatb.2014.11.016Panizza, M., & Cerisola, G. (2009). Direct And Mediated Anodic Oxidation of Organic Pollutants. Chemical Reviews, 109(12), 6541-6569. doi:10.1021/cr9001319Comninellis, C. (1994). Electrocatalysis in the electrochemical conversion/combustion of organic pollutants for waste water treatment. Electrochimica Acta, 39(11-12), 1857-1862. doi:10.1016/0013-4686(94)85175-1Martínez-Huitle, C. A., Ferro, S., & De Battisti, A. (2005). Electrochemical Incineration in the Presence of Halides. Electrochemical and Solid-State Letters, 8(11), D35. doi:10.1149/1.2042628Scialdone, O., Galia, A., Guarisco, C., Randazzo, S., & Filardo, G. (2008). Electrochemical incineration of oxalic acid at boron doped diamond anodes: Role of operative parameters. Electrochimica Acta, 53(5), 2095-2108. doi:10.1016/j.electacta.2007.09.007Scialdone, O., Randazzo, S., Galia, A., & Filardo, G. (2009). Electrochemical oxidation of organics at metal oxide electrodes: The incineration of oxalic acid at IrO2–Ta2O5 (DSA-O2) anode. Electrochimica Acta, 54(4), 1210-1217. doi:10.1016/j.electacta.2008.08.064Scialdone, O. (2009). Electrochemical oxidation of organic pollutants in water at metal oxide electrodes: A simple theoretical model including direct and indirect oxidation processes at the anodic surface. Electrochimica Acta, 54(26), 6140-6147. doi:10.1016/j.electacta.2009.05.066Kapałka, A., Lanova, B., Baltruschat, H., Fóti, G., & Comninellis, C. (2008). Electrochemically induced mineralization of organics by molecular oxygen on boron-doped diamond electrode. Electrochemistry Communications, 10(9), 1215-1218. doi:10.1016/j.elecom.2008.06.005Kapałka, A., Fóti, G., & Comninellis, C. (2007). Kinetic modelling of the electrochemical mineralization of organic pollutants for wastewater treatment. Journal of Applied Electrochemistry, 38(1), 7-16. doi:10.1007/s10800-007-9365-6Kapałka, A., Fóti, G., & Comninellis, C. (2009). The importance of electrode material in environmental electrochemistry. Electrochimica Acta, 54(7), 2018-2023. doi:10.1016/j.electacta.2008.06.045Kapałka, A., Baltruschat, H., & Comninellis, C. (2011). Electrochemical Oxidation of Organic Compounds Induced by Electro-Generated Free Hydroxyl Radicals on BDD Electrodes. Synthetic Diamond Films, 237-260. doi:10.1002/9781118062364.ch10Martínez-Huitle, C. A., Quiroz, M. A., Comninellis, C., Ferro, S., & Battisti, A. D. (2004). Electrochemical incineration of chloranilic acid using Ti/IrO2, Pb/PbO2 and Si/BDD electrodes. Electrochimica Acta, 50(4), 949-956. doi:10.1016/j.electacta.2004.07.035Scialdone, O., Randazzo, S., Galia, A., & Silvestri, G. (2009). Electrochemical oxidation of organics in water: Role of operative parameters in the absence and in the presence of NaCl. Water Research, 43(8), 2260-2272. doi:10.1016/j.watres.2009.02.014S. Trasatti (Ed.) inStudies in Physical and Theoretical Chemistry. Vol. 11. Electrodes of Conductive Metallic oxides. Part. A-B Elsevier Science Publishers Amsterdam 1980/1981.Trasatti, S. (2000). Electrocatalysis: understanding the success of DSA®. Electrochimica Acta, 45(15-16), 2377-2385. doi:10.1016/s0013-4686(00)00338-8Ch. Comninellis G. ChenPanizza, M., Michaud, P. A., Cerisola, G., & Comninellis, C. (2001). Anodic oxidation of 2-naphthol at boron-doped diamond electrodes. Journal of Electroanalytical Chemistry, 507(1-2), 206-214. doi:10.1016/s0022-0728(01)00398-9Iniesta, J. (2001). Electrochemical oxidation of phenol at boron-doped diamond electrode. Electrochimica Acta, 46(23), 3573-3578. doi:10.1016/s0013-4686(01)00630-2Scialdone, O., Guarisco, C., & Galia, A. (2011). Oxidation of organics in water in microfluidic electrochemical reactors: Theoretical model and experiments. Electrochimica Acta, 58, 463-473. doi:10.1016/j.electacta.2011.09.073Polcaro, A. M., Mascia, M., Palmas, S., & Vacca, A. (2002). Kinetic Study on the Removal of Organic Pollutants by an Electrochemical Oxidation Process. Industrial & Engineering Chemistry Research, 41(12), 2874-2881. doi:10.1021/ie010669uSubba Rao, A. N., & Venkatarangaiah, V. T. (2013). Metal oxide-coated anodes in wastewater treatment. Environmental Science and Pollution Research, 21(5), 3197-3217. doi:10.1007/s11356-013-2313-6Wu, W., Huang, Z.-H., & Lim, T.-T. (2014). Recent development of mixed metal oxide anodes for electrochemical oxidation of organic pollutants in water. Applied Catalysis A: General, 480, 58-78. doi:10.1016/j.apcata.2014.04.035Martínez-Huitle, C. A., Rodrigo, M. A., Sirés, I., & Scialdone, O. (2015). Single and Coupled Electrochemical Processes and Reactors for the Abatement of Organic Water Pollutants: A Critical Review. Chemical Reviews, 115(24), 13362-13407. doi:10.1021/acs.chemrev.5b00361Moreira, F. C., Boaventura, R. A. R., Brillas, E., & Vilar, V. J. P. (2017). Electrochemical advanced oxidation processes: A review on their application to synthetic and real wastewaters. Applied Catalysis B: Environmental, 202, 217-261. doi:10.1016/j.apcatb.2016.08.037Berenguer, R., Valdés-Solís, T., Fuertes, A. B., Quijada, C., & Morallón, E. (2008). Cyanide and Phenol Oxidation on Nanostructured Co[sub 3]O[sub 4] Electrodes Prepared by Different Methods. Journal of The Electrochemical Society, 155(7), K110. doi:10.1149/1.2917210Ch. Comninellis Electrochemical treatment of waste water containing phenol Trans. IChemE1992 70 219–224.Stucki, S., K�tz, R., Carcer, B., & Suter, W. (1991). Electrochemical waste water treatment using high overvoltage anodes Part II: Anode performance and applications. Journal of Applied Electrochemistry, 21(2), 99-104. doi:10.1007/bf01464288Comninellis, C., & Pulgarin, C. (1993). Electrochemical oxidation of phenol for wastewater treatment using SnO2, anodes. Journal of Applied Electrochemistry, 23(2). doi:10.1007/bf00246946Rodgers, J. D., Jedral, W., & Bunce, N. J. (1999). Electrochemical Oxidation of Chlorinated Phenols. Environmental Science & Technology, 33(9), 1453-1457. doi:10.1021/es9808189Montilla, F., Morallón, E., & Vázquez, J. L. (2005). Evaluation of the Electrocatalytic Activity of Antimony-Doped Tin Dioxide Anodes toward the Oxidation of Phenol in Aqueous Solutions. Journal of The Electrochemical Society, 152(10), B421. doi:10.1149/1.2013047CORREA-LOZANO, B., COMNINELLIS, C., & BATTISTI, A. D. (1997). Journal of Applied Electrochemistry, 27(8), 970-974. doi:10.1023/a:1018414005000VICENT, F., MORALLO´N, E., QUIJADA, C., L.VA´ZQUEZ, J., ALDAZ, A., & CASES, F. (1998). Journal of Applied Electrochemistry, 28(6), 607-612. doi:10.1023/a:1003250118996Forti, J. C., Olivi, P., & de Andrade, A. R. (2001). Characterisation of DSA®-type coatings with nominal composition Ti/Ru0.3Ti(0.7−x)SnxO2 prepared via a polymeric precursor. Electrochimica Acta, 47(6), 913-920. doi:10.1016/s0013-4686(01)00791-5Montilla, F., Morallón, E., De Battisti, A., & Vázquez, J. L. (2004). Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 1. Electrochemical Characterization. The Journal of Physical Chemistry B, 108(16), 5036-5043. doi:10.1021/jp037480bBerenguer, R., La Rosa-Toro, A., Quijada, C., & Morallón, E. (2008). Origin of the Deactivation of Spinel CuxCo3−xO4/Ti Anodes Prepared by Thermal Decomposition. The Journal of Physical Chemistry C, 112(43), 16945-16952. doi:10.1021/jp804403xAdams, B., Tian, M., & Chen, A. (2009). Design and electrochemical study of SnO2-based mixed oxide electrodes. Electrochimica Acta, 54(5), 1491-1498. doi:10.1016/j.electacta.2008.09.034Berenguer, R., Sieben, J. M., Quijada, C., & Morallón, E. (2014). Pt- and Ru-Doped SnO2–Sb Anodes with High Stability in Alkaline Medium. ACS Applied Materials & Interfaces, 6(24), 22778-22789. doi:10.1021/am506958kBerenguer, R., Sieben, J. M., Quijada, C., & Morallón, E. (2016). Electrocatalytic degradation of phenol on Pt- and Ru-doped Ti/SnO 2 -Sb anodes in an alkaline medium. Applied Catalysis B: Environmental, 199, 394-404. doi:10.1016/j.apcatb.2016.06.038Berenguer, R., Quijada, C., & Morallón, E. (2009). Electrochemical characterization of SnO2 electrodes doped with Ru and Pt. Electrochimica Acta, 54(22), 5230-5238. doi:10.1016/j.electacta.2009.04.016A. J. Bard L. R. Faulkner (Eds.) inElectrochemical Methods John Wiley& Sons New York 1980.Montilla, F., Morallón, E., De Battisti, A., Benedetti, A., Yamashita, H., & Vázquez, J. L. (2004). Preparation and Characterization of Antimony-Doped Tin Dioxide Electrodes. Part 2. XRD and EXAFS Characterization. The Journal of Physical Chemistry B, 108(16), 5044-5050. doi:10.1021/jp0374814He, Y., Li, H., Zou, X., Bai, N., Cao, Y., Cao, Y., … Li, G.-D. (2017). Platinum dioxide activated porous SnO2 microspheres for the detection of trace formaldehyde at low operating temperature. Sensors and Actuators B: Chemical, 244, 475-481. doi:10.1016/j.snb.2017.01.014Santos, A. L., Profeti, D., & Olivi, P. (2005). Electrooxidation of methanol on Pt microparticles dispersed on SnO2 thin films. Electrochimica Acta, 50(13), 2615-2621. doi:10.1016/j.electacta.2004.11.006Doyle, R. L., & Lyons, M. E. G. (2016). The Oxygen Evolution Reaction: Mechanistic Concepts and Catalyst Design. Photoelectrochemical Solar Fuel Production, 41-104. doi:10.1007/978-3-319-29641-8_2Lyons, M. E. G., & Floquet, S. (2011). Mechanism of oxygen reactions at porous oxide electrodes. Part 2—Oxygen evolution at RuO2, IrO2 and IrxRu1−xO2 electrodes in aqueous acid and alkaline solution. Physical Chemistry Chemical Physics, 13(12), 5314. doi:10.1039/c0cp02875dRochefort, D., Dabo, P., Guay, D., & Sherwood, P. M. A. (2003). XPS investigations of thermally prepared RuO2 electrodes in reductive conditions. Electrochimica Acta, 48(28), 4245-4252. doi:10.1016/s0013-4686(03)00611-xGaudet, J., Tavares, A. C., Trasatti, S., & Guay, D. (2005). Physicochemical Characterization of Mixed RuO2−SnO2Solid Solutions. Chemistry of Materials, 17(6), 1570-1579. doi:10.1021/cm048129lConway, B. E. (1999). Electrochemical Supercapacitors. doi:10.1007/978-1-4757-3058-6Ribeiro, J., & de Andrade, A. R. (2006). Investigation of the electrical properties, charging process, and passivation of RuO2–Ta2O5 oxide films. Journal of Electroanalytical Chemistry, 592(2), 153-162. doi:10.1016/j.jelechem.2006.05.004Lodi, G., Zucchini, G., De Battisti, A., Sivieri, E., & Trasatti, S. (1978). On some debated aspects of the behaviour of RuO2 film electrodes. Materials Chemistry, 3(3), 179-188. doi:10.1016/0390-6035(78)90023-8McEvoy, A. J., & Gissler, W. (1982). A ruthenium dioxide‐semiconductor Schottky barrier photovoltaic device. Journal of Applied Physics, 53(2), 1251-1252. doi:10.1063/1.330541Wu, N. L., Hwang, J. Y., Liu, P. Y., Han, C. Y., Kuo, S. L., Liao, K. H., … Wang, S. Y. (2001). Synthesis and Characterization of Sb-Doped SnO[sub 2] Xerogel Electrochemical Capacitor. Journal of The Electrochemical Society, 148(6), A550. doi:10.1149/1.1368099Sugimoto, W., Kizaki, T., Yokoshima, K., Murakami, Y., & Takasu, Y. (2004). Evaluation of the pseudocapacitance in RuO2 with a RuO2/GC thin film electrode. Electrochimica Acta, 49(2), 313-320. doi:10.1016/j.electacta.2003.08.013Ardizzone, S., Fregonara, G., & Trasatti, S. (1990). «Inner» and «outer» active surface of RuO2 electrodes. Electrochimica Acta, 35(1), 263-267. doi:10.1016/0013-4686(90)85068-xIwakura, C., & Sakamoto, K. (1985). Effect of Active Layer Composition on the Service Life of ( SnO2 and RuO2 ) ‐ Coated Ti Electrodes in Sulfuric Acid Solution. Journal of The Electrochemical Society, 132(10), 2420-2423. doi:10.1149/1.2113590J. O. M. Bockris A. K. N. Reddy M. E. Gamboa-AldecoDoyle, R. L., & Lyons, M. E. G. (2013). An electrochemical impedance study of the oxygen evolution reaction at hydrous iron oxide in base. Physical Chemistry Chemical Physics, 15(14), 5224. doi:10.1039/c3cp43464hMatsumoto, Y., & Sato, E. (1986). Electrocatalytic properties of transition metal oxides for oxygen evolution reaction. Materials Chemistry and Physics, 14(5), 397-426. doi:10.1016/0254-0584(86)90045-3Gattrell, M., & Kirk, D. W. (1993). A Study of the Oxidation of Phenol at Platinum and Preoxidized Platinum Surfaces. Journal of The Electrochemical Society, 140(6), 1534-1540. doi:10.1149/1.2221598Lapuente, R., Cases, F., Garcés, P., Morallón, E., & Vázquez, J. . (1998). A voltammetric and FTIR–ATR study of the electropolymerization of phenol on platinum electrodes in carbonate medium. Journal of Electroanalytical Chemistry, 451(1-2), 163-171. doi:10.1016/s0022-0728(98)00098-9Lapuente, R., Quijada, C., Huerta, F., Cases, F., & Vázquez, J. L. (2003). X-Ray Photoelectron Spectroscopy Study of the Composition of Polyphenol Films Formed on Pt by Electropolymerisation of Phenol in the Presence of Sulphide in Carbonate Medium. Polymer Journal, 35(12), 911-919. doi:10.1295/polymj.35.911Panić, V. V., Dekanski, A. B., Vidaković, T. R., Mišković-Stanković, V. B., Javanović, B. Ž., & Nikolić, B. Ž. (2004). Oxidation of phenol on RuO2–TiO2/Ti anodes. Journal of Solid State Electrochemistry, 9(1), 43-54. doi:10.1007/s10008-004-0559-0Feng, Y. ., & Li, X. . (2003). Electro-catalytic oxidation of phenol on several metal-oxide electrodes in aqueous solution. Water Research, 37(10), 2399-2407. doi:10.1016/s0043-1354(03)00026-5Li, X., Cui, Y., Feng, Y., Xie, Z., & Gu, J.-D. (2005). Reaction pathways and mechanisms of the electrochemical degradation of phenol on different electrodes. Water Research, 39(10), 1972-1981. doi:10.1016/j.watres.2005.02.021Zanta, C. L. P. S., de Andrade, A. R., & Boodts, J. F. C. (2000). Journal of Applied Electrochemistry, 30(4), 467-474. doi:10.1023/a:1003942411733Cestarolli, D. T., & de Andrade, A. R. (2007). Electrochemical Oxidation of Phenol at Ti∕Ru[sub 0.3]Pb[sub (0.7−x)]Ti[sub x]O[sub y] Electrodes in Aqueous Media. Journal of The Electrochemical Society, 154(2), E25. doi:10.1149/1.2405722Wels, B., & Johnson, D. C. (1990). Electrocatalysis of Anodic Oxygen Transfer Reactions: Oxidation of Cyanide at Electrodeposited Copper Oxide Electrodes in Alkaline Media. Journal of The Electrochemical Society, 137(9), 2785-2791. doi:10.1149/1.2087072Berenguer, R., La Rosa-Toro, A., Quijada, C., & Morallón, E. (2017). Electrocatalytic oxidation of cyanide on copper-doped cobalt oxide electrodes. Applied Catalysis B: Environmental, 207, 286-296. doi:10.1016/j.apcatb.2017.01.078Berenguer, R., Quijada, C., La Rosa-Toro, A., & Morallón, E. (2019). Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels. Separation and Purification Technology, 208, 42-50. doi:10.1016/j.seppur.2018.05.02
The distribution of effective tax burdens in four EU countries
National policymakers are increasingly aware that their tax policy options are constrained by international tax competition. Important features of national tax systems - notably the tax mix, tax rates and rules which define the tax base - will influence decisions of firms and individuals regarding the location and (re)structuring of economic activities. The aim of the present paper is twofold: Firstly, we detail the tax mix of four member states of the European Union (Germany, The Netherlands, Spain and United Kingdom). Secondly, the paper aims to trace the distribution of the tax burden over rich and poor households in these four countries. Although tax mix and tax rates differ considerably among the four countries included in the study, the distribution of tax burdens proves to be amazingly similar.Distribution of tax burden, European Union; tax mix of Germany, the Netherlands, Spain and United Kingdom
Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels
[EN] The feasibility of the electrochemical technologies for wastewater treatment greatly relies on the design of
efficient but inexpensive electrocatalysts. It is generally accepted that the so-called ¿non-active¿ anodes (like the
boron-doped diamond (BDD) or SnO2-based anodes), producing highly oxidizing hydroxyl radicals, are the most
promising candidates for pollutants abatement. In this work, the electrocatalytic performance of various cobalt
oxides, pure and doped with Cu or Au, for CN¿ oxidation has been studied and compared with that of conventional
graphite, BDD, SnO2-Sb and SnO2-Sb-Pt. The metal oxide electrodes were prepared by thermal decomposition
of the salt precursors onto Ti. For the M-doped Co3O4 electrodes, the nominal M/Co ratios were Cu/
Co=0.07¿1.00; and Au/Co=0.05¿0.20. The electrodes were characterized by different techniques (XRD, SEM,
EDX, XPS) and their electrocatalytic response was studied by cyclic voltammetry and galvanostatic electrolysis in
a H-type cell in aqueous 0.1M NaOH. The obtained results show that the nature of the dopant plays a key role on
the electrocatalytic behavior of cobalt spinels. Thus, while Cu catalyzes the CN¿ electro-oxidation, Au declines
it. This is explained by the fact that, unlike Au (which segregates as Au-rich particles), Cu is effectively incorporated
into the spinel structure by forming a solid solution (CuxCo3-xO4). In this solid solution, atomic scale
Cu(spinel)-CN¿ specific interactions occur to catalyze the reaction, whereas in segregated Au particles the oxidation
is hindered probably by a too-strong adsorption of cyanide and/or its inaccessibility to oxide active sites.
Electrolysis runs have revealed that ¿active¿ over-saturated Cu-doped spinels (Cu/Co=1.00) exhibit higher
current efficiencies than conventional graphite and ¿non-active¿ BDD and SnO2-based anodes. Hence, we hereby
demonstrate that an inexpensive ¿active¿ electrocatalyst can show even higher efficiency than the most powerful
BDD anode. These results highlight the significance of anode design in the application of the electrochemical
technique for wastewater treatment.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) is gratefully acknowledgedBerenguer, R.; Quijada, C.; La Rosa-Toro, A.; Morallón, E. (2019). Electro-oxidation of cyanide on active and non-active anodes: Designing the electrocatalytic response of cobalt spinels. Separation and Purification Technology. 208:42-50. https://doi.org/10.1016/j.seppur.2018.05.024S425020
Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes
[EN] Copper and copper oxides are well-known excellent catalysts in several chemical processes, but their low mechanical and electrochemical stability restrict their direct utilization as electrodes in electrolytic processes. In this work, the incorporation of copper into cobalt oxide (CuxCo3-xO4) is presented as an excellent approach to obtain highly active and robust copper-based electrocatalysts. Particularly, the electrocatalytic performance of Ti-supported CuxCo3-xO4 electrodes (with 0 <= x <= 1.5) has been studied for the oxidation' of cyanide in alkaline media. Cyclic voltammetry and electrolysis runs show an outstanding effect of Cu on the activity, efficiency and kinetics of spinel CuxCo3-xO4 electrodes for CN(-)electro-oxidation. Despite being active oxides with high activity towards water oxidation, copper saturated (x=1.0) and oversaturated (x=1.5) spinels exhibit unprecedented 100% current efficiencies for the electro-oxidation of CN- in aqueous electrolyte. In situ surface enhanced Raman spectroscopy (SERS) reveals the specific adsorption of CN- ions on surface Cu species to be involved in the electrocatalytic oxidation mechanism. This electrocatalytic activity has been attributed to surface Cu(II) in the spinel lattice. Furthermore, the CuxCo3-xO4 electrodes also display high electrochemical stability. Therefore, they are considered excellent candidates for the sustainable electrochemical elimination of highly toxic cyanides.Financial support from the Spanish Ministerio de Economia y Competitividad and FEDER funds (MAT2016-76595-R, IJCI-2014-20012) and from the Generalitat Valenciana (PROMETEO2013/038) is gratefully acknowledged.Berenguer, R.; La Rosa-Toro, A.; Quijada, C.; Morallon, E. (2017). Electrocatalytic Oxidation of Cyanide on Copper-doped Cobalt Oxide Electrodes. Applied Catalysis B Environmental. 207:286-296. https://doi.org/10.1016/j.apcatb.2017.01.078S28629620
Hydrogen Peroxide in Biocatalysis. A Dangerous Liaison
Hydrogen peroxide is a substrate or side-product in many enzyme-catalyzed reactions. For example, it is a side-product of oxidases, resulting from the re-oxidation of FAD with molecular oxygen, and it is a substrate for peroxidases and other enzymes. However, hydrogen peroxide is able to chemically modify the peptide core of the enzymes it interacts with, and also to produce the oxidation of some cofactors and prostetic groups (e.g., the hemo group). Thus, the development of strategies that may permit to increase the stability of enzymes in the presence of this deleterious reagent is an interesting target. This enhancement in enzyme stability has been attempted following almost all available strategies: site-directed mutagenesis (eliminating the most reactive moieties), medium engineering (using stabilizers), immobilization and chemical modification (trying to generate hydrophobic environments surrounding the enzyme, to confer higher rigidity to the protein or to generate oxidation-resistant groups), or the use of systems capable of decomposing hydrogen peroxide under very mild conditions. If hydrogen peroxide is just a side-product, its immediate removal has been reported to be the best solution. In some cases, when hydrogen peroxide is the substrate and its decomposition is not a sensible solution, researchers coupled one enzyme generating hydrogen peroxide “in situ” to the target enzyme resulting in a continuous supply of this reagent at low concentrations thus preventing enzyme inactivation. This review will focus on the general role of hydrogen peroxide in biocatalysis, the main mechanisms of enzyme inactivation produced by this reactive and the different strategies used to prevent enzyme inactivation caused by this “dangerous liaison”.This work has been supported by grant CTQ2009-07568 from Spanish Ministerio de Ciencia e Innovación. A. Berenguer-Murcia thanks the Spanish Ministerio de Ciencia e Innovación for a Ramon y Cajal fellowship (RyC-2009-03813). Mr. Hernandez is a holder of a MAEC-AECID fellowship
Recurrent gastric lactobezoar in an infant
Lactobezoars are a type of bezoar composed of undigested milk and mucus. The aetiology is likely multifactorial, being classically described in association with pre-term, low-birth weight infants fed with hyperconcentrated formula. The authors present a case of lactobezoar recurrence in a pre-term infant with oesophageal atresia. To our knowledge, this is the first report of recurrence of lactobezoar.info:eu-repo/semantics/publishedVersio
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