276 research outputs found

    Study of the zinc recovery from spent pickling baths by means of an electrochemical membrane reactor using a cation-exchange membrane under galvanostatic control

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    The performance of a cation-exchange membrane (CEM) used for recovering zinc from real spent pickling baths is studied in this work. These spent baths contain high amounts of ZnCl2 and FeCl2 in aqueous HCl media. The results obtained with this membrane are compared with those obtained with an anion-exchange membrane (AEM) treating the same effluent. The effect of the presence or absence of initial zinc in the cathodic compartment is also studied. The absence of initial zinc in the cathodic compartment in the CEM experiments permits iron codeposition. Furthermore, the results obtained with the CEM are worse than those obtained with the AEM for all the figures of merit. This fact shows the need of filling the cathodic compartment with a synthetic zinc solution. The presence of zinc in the cathodic compartment from the beginning of the electrolysis not only inhibits iron codeposition but also favors zinc deposition as the hydrogen evolution reaction becomes a secondary reaction, improving by this way the results of all the figures of merit of the reactor with the CEM. A deep study about the effect of the applied current and the concentration of the synthetic zinc solution placed in the cathodic compartment permits to reach the equilibrium between the zinc transferred through the membrane and that deposited on the cathode. Therefore, the synthetic cathodic zinc is not consumed at any time. Moreover, under this circumstances iron codeposition is also avoided.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). Study of the zinc recovery from spent pickling baths by means of an electrochemical membrane reactor using a cation-exchange membrane under galvanostatic control. Separation and Purification Technology. 132:479-486. https://doi.org/10.1016/j.seppur.2014.05.052S47948613

    BDD anodic treatment of 6:2 fluorotelomer sulfonate (6:2 FTSA). Evaluation of operating variables and by-product formation

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    The concerns about the undesired impacts on human health and the environment of long chain perfluorinated alkyl substances (PFASs) have driven industrial initiatives to replace PFASs by shorter chain fluorinated homologues. 6:2 fluorotelomer sulfonic acid (6:2 FTSA) is applied as alternative to PFOS in metal plating and fluoropolymer manufacture. This study reports the electrochemical treatment of aqueous 6:2 FTSA solutions on microcrystalline BDD anodes. Bench scale batch experiments were performed, focused on assessing the effect of the electrolyte and the applied current density (5-600 A m-2) on the removal of 6:2 FTSA, the reduction of total organic carbon (TOC) and the fluoride release. Results showed that at the low range of applied current density (J=50 A m-2), using NaCl, Na2SO4 and NaClO4, the electrolyte exerted a minimal effect on removal rates. The formation of toxic inorganic chlorine species such as ClO4- was not observed. When using Na2SO4 electrolyte, increasing the applied current density to 350-600 A m-2 promoted a notable enhancement of the 6:2 FTSA removal and defluorination rates, pointing to the positive contribution of electrogenerated secondary oxidants to the overall removal rate. 6:2 FTSA was transformed into shorter-chain PFCAs, and eventually into CO2 and fluoride, as TOC reduction was >90%. Finally, it was demonstrated that diffusion in the liquid phase was controlling the overall kinetic rate, although with moderate improvements due to secondary oxidants at very high current densities.Support from MINECO and SPAIN-FEDER 2014–2020 to project CTM2016-75509-R and to the Spanish Excellence Network E3TECH (CTQ2015-71650-RDT) is acknowledged. J. Carrillo-Abad thanks the Generalitat Valenciana for granting a post doctoral fellowship (APOSTD/2015/019). The authors are thankful to Dr. R. Buck (Chemours Co.) for kindly providing samples of Capstone FS10

    Effluents from the copper electrorefining as a secondary source of antimony: Role of mass transfer on the recovery by electrodeposition

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    [EN] The limited availability of antimony has increased the need for exploiting alternative sources to its direct extraction from stibnite deposits. Furthermore, introducing recovery techniques in industries where antimony is released in wastewaters leads to more responsible production routes. In this work, electrodeposition is employed to recover the antimony present in a secondary waste effluent of the copper electrorefining that is highly concentrated in hydrochloric acid. The electrochemical characterization of the system was conducted by voltammetry to identify a range of suitable operating conditions for the potentiostatic and galvanostatic electro-recovery of antimony. In potentiostatic mode, the progress of the secondary electrode reactions of hydrogen and chlorine evolution at potentials more cathodic than ¿0.38 V vs. Ag/AgCl causes the detachment and redissolution of the deposited antimony. Operating under galvanostatic control, similar effects were observed when the limiting current density is exceeded. Current efficiency and specific energy consumption values above 50 % and below 65 kW·h·kg¿1, were achieved below the limiting current density (1.265 mA·cm¿2). The operational range where electrodeposition of antimony is accelerated at increasing current densities can be broadened at intensified hydrodynamic conditions and higher concentrations of antimony. The detrimental effect of the hydrogen evolution reaction on the recovery of antimony decreases at high HCl concentrations.The authors thank the financial support from the Agencia Estatal de Investigacion (AEI/10.13039/501100011033) (Spain) under the project PCI2019-103535 and by FEDER A way of making Europe. Funding for open access charge: CRUE-Universitat Politecnica de Valencia.Hernández-Pérez, L.; Carrillo-Abad, J.; Pérez-Herranz, V.; Montañés, M.; Martí Calatayud, MC. (2023). Effluents from the copper electrorefining as a secondary source of antimony: Role of mass transfer on the recovery by electrodeposition. Desalination. 549. https://doi.org/10.1016/j.desal.2022.11632254

    Enhanced Atenolol oxidation by ferrites photoanodes grown on ceramic SnO2-Sb2O3 anodes

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    The increase in the consumption of pharmaceutical compounds has caused the increment of their presence in different body waters. β-blockers are one of the most dangerous even at low concentrations (ng L−1). Anodic oxidation with a boron-doped diamond (BDD) anode presents good results to remove these compounds. However, since this anode is expensive, some cheaper materials are under study. In this work, Sb-doped SnO2 ceramic anodes (BCE) coated with Zn or Cd ferrites, in order to provide photocatalytic properties, have been applied to the degradation of the Atenolol (ATL) β-blocker. Increasing the applied current increased ATL degradation and mineralization but caused a decrease in mineralization current efficiency (MCE) and an increase in energy consumption (ETOC). Additionally, light irradiation enhanced the ATL mineralization rate between 10% and 20% for both ferrites, although this increase was higher for the cadmium ferrite one. Finally, when the ferrites were compared with BDD and BCE anodes, the oxidizing power of the different anodic materials can be ordered as follows BDD> Cd-Fe> Zn-Fe> BCE. Therefore, both ferrites improved the BCE performance but only the cadmium one appeared as an alternative to the BDD, especially for MCE and ETOC, reaching values of 15% and 0.5 kWh gTOC−1, respectively

    Electrochemical Study of a Simulated Spent Pickling Solution

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    [EN] The electrochemical behaviour of the main components of the rinsing pickling solutions of the hot dip galvanizing industry, Zn(2+) and Fe(2+) in HCl, was studied by cyclic voltammetry. The effect of different variables (such as the scan rate, the inversion potential, the addition of zinc, stirring of the solution and the presence of iron) on the current-potential curves was studied. The electrochemical reduction of zinc proceeded by a typical nucleation process. Decreasing the HCl concentration enhanced the zinc UPD process because of the less influence of the hydrogen evolution reaction (HER), and a prepeak corresponding to the zinc UPD process was observed previously to the zinc OPD step. The effect of the scan rate on the OPD peak was studied and showed that the Zn(2+) reduction was an irreversible process which was not only controlled by diffusion but also charge transfer kinetics. The diffusion coefficient of zinc was calculated (1.66. 10(-9) m(2) s(-1)). In view of iron deposition, it was confirmed that the pH is an essentially important factor and at low pH values was virtually impossible to deposit iron. The electrochemical study of mixtures containing both zinc and iron showed that the presence of zinc produced an inhibition of the iron deposition process which was confirmed by the observation of the deposits. The SEM images revealed only the presence of zinc grains. However, if the ratio Fe(II)/Zn(II) was higher, the voltammograms main features were more similar to those obtained for pure iron solutions.Montserrat Garcia Gabaldón wants 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.García Gabaldón, M.; Carrillo Abad, J.; Ortega Navarro, EM.; Pérez Herranz, V. (2011). Electrochemical Study of a Simulated Spent Pickling Solution. International Journal of Electrochemical Science. 6(2):506-519. http://hdl.handle.net/10251/63617S5065196

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

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    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 low-cost 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

    Recerca i tecnologia en enginyeria gràfica i disseny a la Universitat Politècnica de Catalunya

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    Els temps canvien cada vegada més ràpidament, i a la universitat això encara es nota més. L’històric departament d‘Expressió Gràfica a l’Enginyeria (EGE) de la Universitat Politècnica de Catalunya, garant d’una docència de Grau, Màster i Doctorat de qualitat i adaptada a les necessitats de la societat, emprèn l’any 2020 amb una proposta de canvi de nom per adaptar-se al nous coneixements que estan esdevenint la seva matèria principal, al voltant de l’enginyeria gràfica i el disseny. Les àrees de recerca del centenar de professors que formen el departament són àmplies i variades, i sempre en col·laboració en diversos grups tant de la pròpia UPC com d’altres universitats. Una recerca avançada, de caràcter pluridisciplinari, on s'apliquen creativitat i innovació com a eines de coneixement, implicats en un territori ampli, i situats als diferents campus de la UPC. En els capítols d’aquest llibre podeu veure una petita mostra d’aquesta recerca tecnològica en camps ben variats.Postprint (published version

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Measurement of nuclear modification factors of gamma(1S)), gamma(2S), and gamma(3S) mesons in PbPb collisions at root s(NN)=5.02 TeV

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    The cross sections for ϒ(1S), ϒ(2S), and ϒ(3S) production in lead-lead (PbPb) and proton-proton (pp) collisions at √sNN = 5.02 TeV have been measured using the CMS detector at the LHC. The nuclear modification factors, RAA, derived from the PbPb-to-pp ratio of yields for each state, are studied as functions of meson rapidity and transverse momentum, as well as PbPb collision centrality. The yields of all three states are found to be significantly suppressed, and compatible with a sequential ordering of the suppression, RAA(ϒ(1S)) > RAA(ϒ(2S)) > RAA(ϒ(3S)). The suppression of ϒ(1S) is larger than that seen at √sNN = 2.76 TeV, although the two are compatible within uncertainties. The upper limit on the RAA of ϒ(3S) integrated over pT, rapidity and centrality is 0.096 at 95% confidence level, which is the strongest suppression observed for a quarkonium state in heavy ion collisions to date. © 2019 The Author(s). Published by Elsevier B.V. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). Funded by SCOAP3.Peer reviewe

    Electroweak production of two jets in association with a Z boson in proton-proton collisions root s =13 TeV

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    A measurement of the electroweak (EW) production of two jets in association with a Z boson in proton-proton collisions at root s = 13 TeV is presented, based on data recorded in 2016 by the CMS experiment at the LHC corresponding to an integrated luminosity of 35.9 fb(-1). The measurement is performed in the lljj final state with l including electrons and muons, and the jets j corresponding to the quarks produced in the hard interaction. The measured cross section in a kinematic region defined by invariant masses m(ll) > 50 GeV, m(jj) > 120 GeV, and transverse momenta P-Tj > 25 GeV is sigma(EW) (lljj) = 534 +/- 20 (stat) fb (syst) fb, in agreement with leading-order standard model predictions. The final state is also used to perform a search for anomalous trilinear gauge couplings. No evidence is found and limits on anomalous trilinear gauge couplings associated with dimension-six operators are given in the framework of an effective field theory. The corresponding 95% confidence level intervals are -2.6 <cwww/Lambda(2) <2.6 TeV-2 and -8.4 <cw/Lambda(2) <10.1 TeV-2. The additional jet activity of events in a signal-enriched region is also studied, and the measurements are in agreement with predictions.Peer reviewe
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