Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation

An electrochemical reactor was developed to recover zinc from the spent pickling solutions coming from the hot dip galvanizing industry. These solutions mainly contain ZnCl2 and FeCl2 in aqueous HCl media. The effect of the applied potential on the figures of merit (fractional conversion, current efficiency, space-time yield and specific energy consumption) of the electrochemical reactor was analysed. Voltammetric experiments were performed previously in order to select the optimum conditions to be applied in the electrolysis experiments. From the I-V curves it was inferred that bulk zinc deposition started from potential values more cathodic than -0.99 V. The hydrogen evolution reaction (HER) appeared from -0.45 V and masked the zinc cathodic peak C1, related to bulk zinc deposition, at high HCl concentrations. The presence of HCl inhibited iron deposition in synthetic samples. The additives present in the real baths, which diminish the massive hydrogen generation, allowed the observation of peak C1. The potential values to be applied in the electrolysis experiments were chosen from the voltammetric experiments and ranged between -1 V and -1.75 V. In the absence of iron in solution, as the electrode potential was shifted towards more negative values, the space-time yield of zinc and its fractional conversion increased because of the increase in the electrode roughness and the hydrogen turbulence-promoting action. Simultaneously, the specific energy consumption decreased initially due to the increase in the zinc conversion rate but decreased for the most cathodic potential value due to HER. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+/Fe3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution for the most cathodic potential values. On the contrary, the additives present in the real spent pickling baths avoided the adverse effects of iron, and zinc electrodeposition was possible even at high cathodic potential values. In fact, a potential value of -1.75 V was selected as the optimum since the conversion, the current efficiency and the space time yield obtained in the real baths were relatively high.Authors want to express their gratitude to the Universidad Politecnica de Valencia for the economical support in the project reference PAID-06-08, and to the Generalitat Valenciana for the financing of the project reference GV/2010/029.Carrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2011). Electrochemical recovery of zinc from the spent pickling baths coming from the hot dip galvanizing industry. Potentiostatic operation. Separation and Purification Technology. 81(2):200-207. https://doi.org/10.1016/j.seppur.2011.07.029S20020781

Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation

The performance of a one- and two-compartment electrochemical reactor under galvanostatic control for zinc recovery present in the spent pickling solutions is studied in this paper. These solutions, which mainly contain ZnCl 2 and FeCl 2 in aqueous HCl media, come from the hot dip galvanizing industry. The effect of the anion-exchange membrane (AEM) on the figures of merit of the electrochemical reactor is analyzed. In the absence of iron in solution, as the current value was shifted towards more negative values, the zinc fractional conversion increased because of the increase in the zinc reduction rate. However, the increase in current values made current efficiency decrease due to the hydrogen-reduction side reaction, which caused an increment in the specific energy consumption. The presence of iron in synthetic solutions led to a decrease in current efficiency associated with the reverse redox Fe 2+/Fe 3+ system and to the enhancement of the HER, which also induced increments in the local pH and the subsequent zinc redissolution. These adverse effects related to the presence of iron could be minimized by the interposition of an AEM. In this case, the zinc redissolution was eliminated which enabled zinc conversion values close to 100% together with higher current efficiencies as the consumption of current by the system Fe 2+/Fe 3+ was diminished. © 2012 Elsevier B.V. All rights reserved.Authors want to express their gratitude to the Universidad Politecnica de Valencia for the economic support in the Project Reference PAID-06-08, and to the Generalitat Valenciana for the financing of the Project Reference GV/2010/029.Carrillo Abad, J.; García Gabaldón, M.; Ortega Navarro, EM.; Pérez-Herranz, V. (2012). Recovery of zinc from spent pickling solutions using an electrochemical reactor in presence and absence of an anion-exchange membrane: Galvanostatic operation. Separation and Purification Technology. 98:366-374. https://doi.org/10.1016/j.seppur.2012.08.006S3663749

Treatment of spent pickling baths coming from hot dip galvanizing by means of an electrochemical membrane reactor

The performance of a one (OCR) and a two-compartment electrochemical reactor in the presence of a cation-exchange membrane (CEM) for the zinc recovery present in the spent pickling baths is analyzed in this paper under galvanostatic control. These solutions, which mainly contain ZnCl2 and FeCl2 in aqueous HCl media, come from the hot dip galvanizing industry. The effect of the applied current, the dilution factor of the baths and the presence or absence of initial cathodic zinc is also studied. For the 1:50 diluted spent bath, OCR experiments initially present higher values of the figures of merit than those obtained in the presence of the CEM since zinc is close to the cathode from the first electrolysis instants. However, at long electrolysis times, OCR presents zinc redissolution for all the current values tested due to the chlorine and iron presence close to the zinc deposits. In addition, the iron codeposition phenomenon is also observed in the OCR experiments when pH values are close to 2. On the other hand, CEM experiments become very similar to the OCR experiments at long time values since the CEM under these experimental conditions prevents zinc redissolution phenomenon and also iron codeposition. When the 1:50 diluted bath is concentred to 1:10, OCR experiments present the same tendency as that observed for the 1:50 dilution factor but the effect of zinc redissolution is increased due to the greater amount of chlorine generated in the anode. Under these experimental conditions, iron deposition has also been observed in the presence of the cation-exchange membrane as the rate of zinc deposition is greater than that of zinc transport through the membrane, and the zinc/iron ratio in the cathodic compartment is not high enough to prevent iron codeposition. In both cases, the pH values when iron codeposits with zinc are close to 2 and the zinc/iron ratio is below 0.6. The presence of initial zinc in the cathodic compartment of the electrochemical reactor enhances the reactor performance since it allows the zinc–iron separation in one single step and avoids the zinc redissolution phenomenon.The authors want to express their gratitude to the Generalitat Valenciana for a postgraduate grant (GV/2010/029) and to the Ministerio de Economia y Competitividad for financing the project number CTQ2012-37450-C02-01/PPQ.Carrillo Abad, J.; García Gabaldón, M.; Pérez Herranz, V. (2014). Treatment of spent pickling baths coming from hot dip galvanizing by means of an electrochemical membrane reactor. Desalination. 343:38-47. https://doi.org/10.1016/j.desal.2013.11.040S384734

Tracking homogeneous reactions during electrodialysis of organic acids via EIS

[EN] Organic acids are highly valuable platform chemicals that can be obtained from bioresources and subsequently transformed into a wide spectrum of profitable consumer goods. After their synthesis, organic acids need to be separated from other by-products and conveniently upconcentrated. Based on the ionic nature of organic acids, electromembrane processes are viable technologies for their recovery. Transport of weak acids through ion- exchange membranes is a complex process influenced by multiple phenomena, i.e. concentration polarization, water dissociation and counterion-membrane interactions. In the present study, the transport of two different organic acids (citric and oxalic acid) through anion-exchange membranes is investigated by means of using linear sweep voltammetry, chronopotentiometry and electrochemical impedance spectroscopy (EIS). Results have shown that, at pH values where multivalent acid anions predominate in solution, a first limiting current density is registered in the current-voltage curves, followed by an increase in membrane resistance. A further increase in current leads to a second limiting current density and a steeper increase in membrane resistance associated with an intensified ion depletion. A strong correlation between polarization curves and electrochemical impedance measurements reveals that such increase in resistance is prompted by generation of Hþ and OH? ions and the concomitant onset of homogeneous reactions in very thin solution layers. The generation of Hþ and OH? ions is tracked by a Gerischer arc in the impedance spectra. As the polarization level increases, the subsequent reaction of multivalent anions into lower-charge acid anions involves the evolution of additional Gerischer arcs. Furthermore, the lower conductivity of the reaction products correlates with the increased system resistance. The characteristic times of these reactions are in the order of milliseconds, thus being only directly accessible with the use of frequency response analysis techniques, such as EIS.M.C. Marti-Calatayud acknowledges the support of Generalitat Valenciana through the funding APOSTD/2017/059.Martí Calatayud, MC.; Evdochenko, E.; Bär, J.; García Gabaldón, M.; Wessling, M.; Pérez-Herranz, V. (2020). Tracking homogeneous reactions during electrodialysis of organic acids via EIS. Journal of Membrane Science. 595:1-10. https://doi.org/10.1016/j.memsci.2019.117592S110595Kiss, A. A., Lange, J.-P., Schuur, B., Brilman, D. W. F., van der Ham, A. G. J., & Kersten, S. R. A. (2016). Separation technology–Making a difference in biorefineries. Biomass and Bioenergy, 95, 296-309. doi:10.1016/j.biombioe.2016.05.021Abels, C., Carstensen, F., & Wessling, M. (2013). Membrane processes in biorefinery applications. Journal of Membrane Science, 444, 285-317. doi:10.1016/j.memsci.2013.05.030Sun, Z., Fridrich, B., de Santi, A., Elangovan, S., & Barta, K. (2018). Bright Side of Lignin Depolymerization: Toward New Platform Chemicals. Chemical Reviews, 118(2), 614-678. doi:10.1021/acs.chemrev.7b00588Wang, M., Ma, J., Liu, H., Luo, N., Zhao, Z., & Wang, F. (2018). Sustainable Productions of Organic Acids and Their Derivatives from Biomass via Selective Oxidative Cleavage of C–C Bond. ACS Catalysis, 8(3), 2129-2165. doi:10.1021/acscatal.7b03790Koutinas, A. A., Vlysidis, A., Pleissner, D., Kopsahelis, N., Lopez Garcia, I., Kookos, I. K., … Lin, C. S. K. (2014). Valorization of industrial waste and by-product streams via fermentation for the production of chemicals and biopolymers. Chemical Society Reviews, 43(8), 2587. doi:10.1039/c3cs60293aBetiku, E., Emeko, H. A., & Solomon, B. O. (2016). Fermentation parameter optimization of microbial oxalic acid production from cashew apple juice. Heliyon, 2(2), e00082. doi:10.1016/j.heliyon.2016.e00082Regestein, L., Klement, T., Grande, P., Kreyenschulte, D., Heyman, B., Maßmann, T., … Büchs, J. (2018). From beech wood to itaconic acid: case study on biorefinery process integration. Biotechnology for Biofuels, 11(1). doi:10.1186/s13068-018-1273-yDi Marino, D., Jestel, T., Marks, C., Viell, J., Blindert, M., Kriescher, S. M. A., … Wessling, M. (2019). Carboxylic Acids Production via Electrochemical Depolymerization of Lignin. ChemElectroChem, 6(5), 1434-1442. doi:10.1002/celc.201801676López-Garzón, C. S., & Straathof, A. J. J. (2014). Recovery of carboxylic acids produced by fermentation. Biotechnology Advances, 32(5), 873-904. doi:10.1016/j.biotechadv.2014.04.002Handojo, L., Wardani, A. K., Regina, D., Bella, C., Kresnowati, M. T. A. P., & Wenten, I. G. (2019). Electro-membrane processes for organic acid recovery. RSC Advances, 9(14), 7854-7869. doi:10.1039/c8ra09227cStodollick, J., Femmer, R., Gloede, M., Melin, T., & Wessling, M. (2014). Electrodialysis of itaconic acid: A short-cut model quantifying the electrical resistance in the overlimiting current density region. Journal of Membrane Science, 453, 275-281. doi:10.1016/j.memsci.2013.11.008Brauns, E. (2008). Towards a worldwide sustainable and simultaneous large-scale production of renewable energy and potable water through salinity gradient power by combining reversed electrodialysis and solar power? Desalination, 219(1-3), 312-323. doi:10.1016/j.desal.2007.04.056Abu Khalla, S., & Suss, M. E. (2019). Desalination via chemical energy: An electrodialysis cell driven by spontaneous electrode reactions. Desalination, 467, 257-262. doi:10.1016/j.desal.2019.04.031Chandra, A., Tadimeti, J. G. D., & Chattopadhyay, S. (2018). Transport hindrances with electrodialytic recovery of citric acid from solution of strong electrolytes. Chinese Journal of Chemical Engineering, 26(2), 278-292. doi:10.1016/j.cjche.2017.05.010Andersen, S. J., Hennebel, T., Gildemyn, S., Coma, M., Desloover, J., Berton, J., … Rabaey, K. (2014). Electrolytic Membrane Extraction Enables Production of Fine Chemicals from Biorefinery Sidestreams. Environmental Science & Technology, 48(12), 7135-7142. doi:10.1021/es500483wChai, P., Wang, J., & Lu, H. (2015). The cleaner production of monosodium l -glutamate by resin-filled electro-membrane reactor. Journal of Membrane Science, 493, 549-556. doi:10.1016/j.memsci.2015.07.023Fu, L., Gao, X., Yang, Y., Aiyong, F., Hao, H., & Gao, C. (2014). Preparation of succinic acid using bipolar membrane electrodialysis. Separation and Purification Technology, 127, 212-218. doi:10.1016/j.seppur.2014.02.028Kumar, M., Tripathi, B. P., & Shahi, V. K. (2009). Electro-membrane reactor for separation and in situ ion substitution of glutamic acid from its sodium salt. Electrochimica Acta, 54(21), 4880-4887. doi:10.1016/j.electacta.2009.04.036Pismenskaya, N., Nikonenko, V., Auclair, B., & Pourcelly, G. (2001). Transport of weak-electrolyte anions through anion exchange membranes. Journal of Membrane Science, 189(1), 129-140. doi:10.1016/s0376-7388(01)00405-7Martí-Calatayud, M. C., Buzzi, D. C., García-Gabaldón, M., Ortega, E., Bernardes, A. M., Tenório, J. A. S., & Pérez-Herranz, V. (2014). Sulfuric acid recovery from acid mine drainage by means of electrodialysis. Desalination, 343, 120-127. doi:10.1016/j.desal.2013.11.031Martí-Calatayud, M. C., Buzzi, D. C., García-Gabaldón, M., Bernardes, A. M., Tenório, J. A. S., & Pérez-Herranz, V. (2014). Ion transport through homogeneous and heterogeneous ion-exchange membranes in single salt and multicomponent electrolyte solutions. Journal of Membrane Science, 466, 45-57. doi:10.1016/j.memsci.2014.04.033Belashova, E. D., Pismenskaya, N. D., Nikonenko, V. V., Sistat, P., & Pourcelly, G. (2017). Current-voltage characteristic of anion-exchange membrane in monosodium phosphate solution. Modelling and experiment. Journal of Membrane Science, 542, 177-185. doi:10.1016/j.memsci.2017.08.002Martí-Calatayud, M., García-Gabaldón, M., & Pérez-Herranz, V. (2018). Mass Transfer Phenomena during Electrodialysis of Multivalent Ions: Chemical Equilibria and Overlimiting Currents. Applied Sciences, 8(9), 1566. doi:10.3390/app8091566Melnikova, E. D., Pismenskaya, N. D., Bazinet, L., Mikhaylin, S., & Nikonenko, V. V. (2018). Effect of ampholyte nature on current-voltage characteristic of anion-exchange membrane. Electrochimica Acta, 285, 185-191. doi:10.1016/j.electacta.2018.07.186Femmer, R., Mani, A., & Wessling, M. (2015). Ion transport through electrolyte/polyelectrolyte multi-layers. Scientific Reports, 5(1). doi:10.1038/srep11583Belloň, T., Polezhaev, P., Vobecká, L., Svoboda, M., & Slouka, Z. (2019). Experimental observation of phenomena developing on ion-exchange systems during current-voltage curve measurement. Journal of Membrane Science, 572, 607-618. doi:10.1016/j.memsci.2018.11.037Rybalkina, O. A., Tsygurina, K. A., Melnikova, E. D., Pourcelly, G., Nikonenko, V. V., & Pismenskaya, N. D. (2019). Catalytic effect of ammonia-containing species on water splitting during electrodialysis with ion-exchange membranes. Electrochimica Acta, 299, 946-962. doi:10.1016/j.electacta.2019.01.068Tanaka, Y. (2010). Water dissociation reaction generated in an ion exchange membrane. Journal of Membrane Science, 350(1-2), 347-360. doi:10.1016/j.memsci.2010.01.010Belova, E. I., Lopatkova, G. Y., Pismenskaya, N. D., Nikonenko, V. V., Larchet, C., & Pourcelly, G. (2006). Effect of Anion-exchange Membrane Surface Properties on Mechanisms of Overlimiting Mass Transfer. The Journal of Physical Chemistry B, 110(27), 13458-13469. doi:10.1021/jp062433fBelova, E., Lopatkova, G., Pismenskaya, N., Nikonenko, V., & Larchet, C. (2006). Role of water splitting in development of electroconvection in ion-exchange membrane systems. Desalination, 199(1-3), 59-61. doi:10.1016/j.desal.2006.03.142Zabolotskiy, V. I., But, A. Y., Vasil’eva, V. I., Akberova, E. M., & Melnikov, S. S. (2017). Ion transport and electrochemical stability of strongly basic anion-exchange membranes under high current electrodialysis conditions. Journal of Membrane Science, 526, 60-72. doi:10.1016/j.memsci.2016.12.028Papagianni, M. (2007). Advances in citric acid fermentation by Aspergillus niger: Biochemical aspects, membrane transport and modeling. Biotechnology Advances, 25(3), 244-263. doi:10.1016/j.biotechadv.2007.01.002Komáromy, P., Bakonyi, P., Kucska, A., Tóth, G., Gubicza, L., Bélafi-Bakó, K., & Nemestóthy, N. (2019). Optimized pH and Its Control Strategy Lead to Enhanced Itaconic Acid Fermentation by Aspergillus terreus on Glucose Substrate. Fermentation, 5(2), 31. doi:10.3390/fermentation5020031Martí-Calatayud, M. C., García-Gabaldón, M., & Pérez-Herranz, V. (2012). Study of the effects of the applied current regime and the concentration of chromic acid on the transport of Ni2+ ions through Nafion 117 membranes. Journal of Membrane Science, 392-393, 137-149. doi:10.1016/j.memsci.2011.12.012Martí-Calatayud, M. C., García-Gabaldón, M., & Pérez-Herranz, V. (2013). Effect of the equilibria of multivalent metal sulfates on the transport through cation-exchange membranes at different current regimes. Journal of Membrane Science, 443, 181-192. doi:10.1016/j.memsci.2013.04.058Butylskii, D. Y., Mareev, S. A., Pismenskaya, N. D., Apel, P. Y., Polezhaeva, O. A., & Nikonenko, V. V. (2018). Phenomenon of two transition times in chronopotentiometry of electrically inhomogeneous ion exchange membranes. Electrochimica Acta, 273, 289-299. doi:10.1016/j.electacta.2018.04.026Moya, A. A. (2016). Electrochemical Impedance of Ion-Exchange Membranes with Interfacial Charge Transfer Resistances. The Journal of Physical Chemistry C, 120(12), 6543-6552. doi:10.1021/acs.jpcc.5b12087Femmer, R., Martí-Calatayud, M. C., & Wessling, M. (2016). Mechanistic modeling of the dielectric impedance of layered membrane architectures. Journal of Membrane Science, 520, 29-36. doi:10.1016/j.memsci.2016.07.055Roghmans, F., Martí-Calatayud, M. C., Abdu, S., Femmer, R., Tiwari, R., Walther, A., & Wessling, M. (2016). Electrochemical impedance spectroscopy fingerprints the ion selectivity of microgel functionalized ion-exchange membranes. Electrochemistry Communications, 72, 113-117. doi:10.1016/j.elecom.2016.09.009Kniaginicheva, E., Pismenskaya, N., Melnikov, S., Belashova, E., Sistat, P., Cretin, M., & Nikonenko, V. (2015). Water splitting at an anion-exchange membrane as studied by impedance spectroscopy. Journal of Membrane Science, 496, 78-83. doi:10.1016/j.memsci.2015.07.050Pismenskaya, N. D., Pokhidnia, E. V., Pourcelly, G., & Nikonenko, V. V. (2018). Can the electrochemical performance of heterogeneous ion-exchange membranes be better than that of homogeneous membranes? Journal of Membrane Science, 566, 54-68. doi:10.1016/j.memsci.2018.08.055Harding, M. S., Tribollet, B., Vivier, V., & Orazem, M. E. (2017). The Influence of Homogeneous Reactions on the Impedance Response of a Rotating Disk Electrode. Journal of The Electrochemical Society, 164(11), E3418-E3428. doi:10.1149/2.0411711jesNikonenko, V., Lebedev, K., Manzanares, J. A., & Pourcelly, G. (2003). Modelling the transport of carbonic acid anions through anion-exchange membranes. Electrochimica Acta, 48(24), 3639-3650. doi:10.1016/s0013-4686(03)00485-

Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate

Cation-exchange membranes made exclusively from ceramic materials have been synthesized by means of the impregnation of microporous ceramic supports with zirconium phosphate. Changes in the pore size distribution and total pore volume of the supports were provoked by the addition of starch as pore former in the fabrication procedure. This allowed the production of supports with increased effective electrical conductivities and with larger pores available for the zirconium phosphate deposition. An improved functionality for the exchange of cations was given to the ceramic membranes by means of their impregnation with the active particles of zirconium phosphate. The ion-exchange properties of the membranes were increased with further impregnation cycles and the resulting current voltage curves showed a similar shape to that typical of commercial polymeric ion-exchange membranes. The production of ionexchange membranes with increased chemical and radiation stability will broaden their applicability for the treatment of specific industrial waste waters, which are very aggressive for the current commercial ion-exchange membranes.Manuel-Cesar Marti-Calatayud wants to express his gratitude to Universitat Politecnica de Valencia for a postgraduate grant (Ref. 2010-12). S. Sales would like to express her gratitude to Ministerio de Ciencia e Investigacion (Spain) for a postgraduate grant (AP2009-4409). This work was supported by Ministerio de Ciencia e Innovacion (Spain) with the project numbers CTQ2008-06750-C02-01/PPQ and CTQ2008-06750-C02-02/PPQ.Martí Calatayud, MC.; García Gabaldón, M.; Pérez-Herranz, V.; Sales, S.; Mestre, S. (2013). Synthesis and electrochemical behavior of ceramic cation-exchange membranes based on zirconium phosphate. Ceramics International. 39(4):4045-4054. https://doi.org/10.1016/j.ceramint.2012.10.255S4045405439

Study of the chlorfenvinphos pesticide removal under different anodic materials and different reactor configuration

The present manuscript focuses on the study of the electrochemical oxidation of the insecticide Chlorfenvinphos (CVP). The assays were carried out under galvanostatic conditions using boron-doped diamond (BDD) and lowcost tin dioxide doped with antimony (Sb-doped SnO2) as anodes. The influence of the operating variables, such as applied current density, presence or absence of a cation-exchange membrane and concentration of supporting electrolyte, was discussed. The results revealed that the higher applied current density the higher degradation and mineralization of the insecticide for both anodes. The presence of the membrane and the highest concentration of Na2SO4 studied (0.1 M) as a supporting electrolyte benefited the oxidation process of CVP using the BDD electrode, while with the ceramic anode the elimination of CVP was lower under these experimental conditions. Although the BDD electrode showed the best performance, ceramic anodes appear as an interesting alternative as they were able to degrade CVP completely for the highest applied current density values. Toxicity tests revealed that the initial solution of CVP was more toxic than the samples treated with the ceramic electrode, while using the BDD electrode the toxicity of the sample increased

Ion transport through homogeneous and heterogeneous ion-exchange membranes in single salt and multicomponent electrolyte solutions

The increasing demand for clean industrial processes has intensified the use of electrodialysis in the treatment of metal containing effluents and encourages the investigation of the different phenomena involved in the transport of metal ions through cation-exchange membranes. Ion sorption, chronopotentiometric and current–voltage characteristics have been obtained to characterize the transport of sodium and iron through homogeneous and heterogeneous cation-exchange membranes. The heterogeneous membranes having a broader pore size distribution showed increased electrical resistances with solutions of trivalent iron, which may be caused by the blockage of the smallest pores by multivalent ions. However, for both types of membranes an unexpected decrease of the electrical resistance with increasing current densities was verified with concentrated solutions of Fe2(SO4)3. This behavior was explained to be a consequence of the dissociation of FeSO4+ ions into more conductive Fe3+ and SO42− ions as the depleting solution layer becomes diluted. When tested with multicomponent mixtures, the homogeneous perfluorosulfonic membranes show an increased preference for Na+ ions at low current densities and, once Na+ ions are depleted from the membrane surface Fe3+ ions are transported preferentially at higher current densities. On the contrary, both Na+ ions and Fe(III) species are responsible for the ion transport through the heterogeneous membranes within the ohmic regime of currents.This work was supported by the Ministerio de Economia y Competitividad (Spain) with the Project number CTQ2012-37450-C02-01/PPQ. M.C. Marti-Calatayud is grateful to the Universitat Politecnica de Valencia for a postgraduate grant (Ref. 2010-12). D.C. Buzzi wants to express her gratitude to CAPES (Brazil) for a postgraduate grant (Proc. BEX 8747/11-3).Martí Calatayud, MC.; Buzzi, DC.; García Gabaldón, M.; Bernardes, AM.; Tenório, JAS.; Pérez Herranz, V. (2014). Ion transport through homogeneous and heterogeneous ion-exchange membranes in single salt and multicomponent electrolyte solutions. Journal of Membrane Science. 466:45-57. https://doi.org/10.1016/j.memsci.2014.04.033S455746

Low-cost inorganic cation exchange membrane for electrodialysis: optimum processing temperature for the cation exchanger

The optimum temperature for fixing zirconium phosphate, obtained by precipitation, on a low-cost ceramic support was determined in order to obtain an inorganic cation exchange membrane for electrodialysis. Zirconium phosphate ion exchange capacity maximised between 450 and 550°C, thus it was considered the optimum processing temperature. The origin of this maximum was investigated by means of X-ray diffraction and termogravimetry and evolved gas analysis. Zirconium phosphate formation by precipitation in the porous network of the support was verified by scanning electron microscopy and energy dispersive X-ray analysis and mercury intrusion porosimetry. The membrane obtained after thermal treatment at 450°C displayed selectivity to the cations present in the spent rinse water of the chromium plating process. This property allows the recovery of chromium by removing the cations through the cation exchange ceramic membrane.The authors wish to express their gratitude to the Spanish Ministry of Science and Innovation for the support given to the research study (National Basic Research Programme, Ref. CTQ2008-06750-C02-02), as well as for the FPU student grant awarded to one of the authors (Ref.: AP2009-4409).Mestre, S.; Sales, S.; Palacios, M.; Lorente, M.; Mallol, G.; Pérez-Herranz, V. (2013). Low-cost inorganic cation exchange membrane for electrodialysis: optimum processing temperature for the cation exchanger. Desalination and Water Treatment. 51(16-18):3317-3324. https://doi.org/10.1080/19443994.2012.749177S331733245116-18Strathmann, H. (2010). Electromembrane Processes: Basic Aspects and Applications. Comprehensive Membrane Science and Engineering, 391-429. doi:10.1016/b978-0-08-093250-7.00048-7Drioli, E., & Fontananova, E. (s. f.). Integrated Membrane Processes. 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(1966). Inorganic ion-exchange membranes and their application to electrodialysis. Desalination, 1(3), 231-246. doi:10.1016/s0011-9164(00)80255-6INAMUDDIN, KHAN, S., SIDDIQUI, W., & KHAN, A. (2007). Synthesis, characterization and ion-exchange properties of a new and novel ‘organic–inorganic’ hybrid cation-exchanger: Nylon-6,6, Zr(IV) phosphate. Talanta, 71(2), 841-847. doi:10.1016/j.talanta.2006.05.042HELEN, M., VISWANATHAN, B., & MURTHY, S. (2007). Synthesis and characterization of composite membranes based on α-zirconium phosphate and silicotungstic acid. Journal of Membrane Science, 292(1-2), 98-105. doi:10.1016/j.memsci.2007.01.018Yu.S. Dzyaz’ko, V.N. Belyakov, N.V. Stefanyak, S.L. Vasilyuk, Anion-exchange properties of composite ceramic membranes containing hydrated zirconium dioxide, Russ. J. Appl. Chem. 79 (2006) 769–773.Linkov, V. ., & Belyakov, V. . (2001). Novel ceramic membranes for electrodialysis. 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Rehabilitación cognitiva en trastornos psiquiátricos graves: aplicación de los subprogramas cognitivos de la terapia psicológica integrada (IPT).

El objetivo del estudio fue conocer los efectos de los subprogramas cognitivos de la Terapia Psicológica Integrada (IPT) en pacientes con trastornos psicóticos. La investigación, de tipo experimental, midió los cambios en los procesos cognitivos básicos y, a su vez, en la sintomatología, las habilidades sociales y de resolución de problemas. Los participantes fueron 32 pacientes en tratamiento ambulatorio diagnosticados de esquizofrenia y trastorno esquizoafectivo (F20 y F21), divididos en dos condiciones: experimental y control. Los participantes del grupo experimental asistieron a un programa de IPT durante seis meses, a razón de dos sesiones semanales. El grupo control no recibió ningún programa terapéutico de rehabilitación. En el análisis de las medidas pre-post tratamiento para el grupo experimental, encontrándose una mejoría estadísticamente significativa tanto para la sintomatología cognitiva (Mpre=4,05 vs Mpost=3,60), como para la afectiva (Mpre= 4,35 vs. Mpost= 4,00) y la negativa (Mpre=4,65 vs Mpost=.4, 25). También, en las medidas del rendimiento se ha podido observar un incremento en el rendimiento (Mpre=12 vs. Mposts=13.95), en la medida de atención selectiva y memoria auditiva. Por último, se encontró una mejora en la satisfacción con la vida (Mpre=55,60 vs. Mpost= 53,67). Los participantes del grupo control, por el contrario, no experimentaron cambios significativos en ninguna de las variables medidas. Se evidencia la eficacia de la implementación de un programa de tratamiento psicológico integrado en la rehabilitación cognitiva de los pacientes psicóticos. Así mismo, se discuten las limitaciones y las implicaciones para futuras aplicaciones de la IPT en esta població