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Toluca de Lerdo, Mexico

Almazan-Sanchez P.T.,National Autonomous University of Mexico | Linares-Hernandez I.,National Autonomous University of Mexico | Martinez-Miranda V.,National Autonomous University of Mexico | Lugo-Lugo V.,Valle de Toluca University | Guadalupe Fonseca-Montes De Oca R.M.,National Autonomous University of Mexico
Catalysis Today

Oxidation-adsorption treatments were applied to improve the biodegradability of wastewater from the manufacture of acrylic resins with methyl methacrylate (MMA). MMA wastewater has an extremely complex composition, with a chemical oxygen demand (COD) concentration of 651.25-g O2/L, total organic carbon (TOC) concentration of 227.86 g/L, N-NH3 concentration of 48.80 g/L, and 352,500-PtCo units. In this study, the effects of operating parameters that include the Fenton reagent dosage, the initial pH, and the reaction time of the treatment efficiencies of the Fenton oxidation process were observed. The improvement in the biodegradability was attributed to the removal of ammonium and organic pollutants from the wastewater, which was confirmed using infrared spectroscopy. After this process, adsorption of organic matter from wastewater was also studied; kinetic and equilibrium adsorption studies were performed to evaluate the effect of the contact time and pH. Pseudo-second-order kinetics represented the experimental data well, and Langmuir and Freundlich isotherm models were tested to represent the data. The maximum adsorption capacity obtained was qm = 1.15 g/g for TOC and 11.65 g/g for COD at optimum conditions. The removal efficiencies of the Fenton adsorption treatment were 96% of color, 58% of TOC, and 60% COD. © 2013 Elsevier B.V. All rights reserved. Source

Velazquez-Pena S.,National Autonomous University of Mexico | Linares-Hernandez I.,National Autonomous University of Mexico | Martinez-Miranda V.,National Autonomous University of Mexico | Barrera-Diaz C.,Autonomous University of Mexico State | And 2 more authors.
Separation Science and Technology (Philadelphia)

The goal of this work was to evaluate the effectiveness of iron and boron-doped-diamond (BDD) as cathodic electrodes on the reduction of Cr(VI) in synthetic and wastewater samples. The pH and electrolyte composition were varied, and the effect on the Cr(VI) reduction rate was measured. The optimized conditions from the synthetic water Cr(VI) reduction experimental data, were tasted on electroplating wastewater. The results indicated that both a pH of 2 and the use of NaCl as an electrolyte significantly increase the Cr(VI) reduction rate for all synthetic systems, especially the iron-BDD system. The Cr(VI) reduction rate in Fe-BDD systems was also affected by nitrate and sulfate ions. In the case of electroplating wastewater, Cr(VI) reduction by BDD cathodes was faster than with iron cathodes, achieving a complete reduction of 180 mg Cr(VI)/L in 25 min, with 40% less sludge produced. The elemental composition of sludge was analyzed using SEM/EDS and X-ray spectroscopy to confirm that iron and chromium precipitated out of the solution. The sludge had a chemical composition of (31.9%) Fe2O3, (29.6%) FeOOH, (21%) FeO, and (17.4%) FeSO4. Therefore, BDD as an electrode material effectively reduces Cr(VI) in electroplating wastewater, and can be effectively scaled up to industrial applications. © 2013 Copyright Taylor and Francis Group, LLC. Source

Belyaeva T.L.,National Autonomous University of Mexico | Danilov A.N.,RAS Research Center Kurchatov Institute | Demyanova A.S.,RAS Research Center Kurchatov Institute | Goncharov S.A.,Skobeltsyn Institute of Nuclear Physics | And 2 more authors.
Physical Review C - Nuclear Physics

Evidence of the 3α-particle condensate character of the Hoyle state (the 02+ state at 7.65 MeV in C12) implies not only an enhanced radius of C12 in this state, which was established by many theoretical calculations and confirmed by the recent diffraction model analysis, but also zero relative angular momenta between clusters. We performed coupled-channels model calculations of the angular distributions of α+12C elastic and inelastic (to the 4.44-MeV 2⊃+, 7.65-MeV 02+, and 9.65-MeV 31- states) scattering at 110 MeV and found the ratio of the empirical spectroscopic factors S(L). As the differential cross sections of these reactions are characterized by pronounced enhancement and strong oscillations at large angles, we assumed a potential scattering in the forward hemisphere and the direct transfer of a Be8 cluster at θc.m. 90⊃° and took into account the direct transfer of Be8 in the ground state and in the first excited 2⊃+ and 4⊃+ states. We found that the cluster configuration with L=0 dominates in the 02+ state, being more than three times larger than that in the ground state. This result provides additional evidence of the condensed structure of the Hoyle state in C12 with a dominance of zero relative angular momentum. The negative-parity 31- excited state in C12 observed above the 3α threshold is also considered to have the 3α-cluster structure. The present calculations described well the structure of the large-angle cross section on this state. We found a positive interference for all allowed α+8Be configurations with a dominance of the p-orbital (69%)α+8Be motion and confirmed the exotic, but hardly a condensed, structure of this state. © 2010 The American Physical Society. Source

Belyaeva T.L.,National Autonomous University of Mexico | Perez-Torres R.,Valle de Toluca University | Ogloblin A.A.,RAS Research Center Kurchatov Institute | Demyanova A.S.,RAS Research Center Kurchatov Institute | And 2 more authors.
Physical Review C - Nuclear Physics

An analysis of the differential cross sections of the C12(d,p)C13 (ground state, or g.s., 1/21+) and Be10(d,p)Be11 (g.s., 1/21-) reactions at the incident deuteron energies of 11.8, 25.9, and 30 MeV for the first system, and 12.0 and 25.0 MeV for the second system has been performed by applying the coupled-reaction-channels method. The spectroscopic factors Sexpt, asymptotic normalization coefficients (ANCs), and rms radii of the last neutron in the ground states and the first excited states of the stable C13 and the radioactive Be11 nuclei were extracted. The existence of neutron halos in the first excited state of C13 and the ground state of Be11 is confirmed. The rms radii of halos in these states were found to be 5.72±0.16 and 8.0±0.2 fm, respectively, in agreement with experimental results. We showed that a halo is also formed in the 0.32 MeV 1/21- excited state of Be11. The halo radius in this state was determined for the first time and was found to be Rh=4.65±0.20 fm. © 2014 American Physical Society. Source

Lugo-Lugo V.,Valle de Toluca University | Lugo-Lugo V.,Autonomous University of Mexico State | Barrera-Diaz C.,Autonomous University of Mexico State | Urena-Nunez F.,Instituto Nacional de Investigaciones Nucleares | And 2 more authors.
Journal of Environmental Management

Trivalent chromium and iron are the products of the traditional reduction of hexavalent chromium by ferrous salts in industrial wastewater. Although there have been a few studies of Cr(III) adsorption, none have considered the effect of Fe(III) on Cr(III) adsorption in a binary system representing expected products of hexavalent chromium in industrial wastewater. The biosorption of Cr(III) and Fe(III) ions onto pretreated ground orange peel in single and binary systems was studied in batch experiments using a variety of techniques. The kinetic results showed a rapid rate of biosorption of Cr(III) and Fe(III) in single and binary systems and mutual interference effects in the competitive binary Cr(III)-Fe(III) system. Second order kinetic models showed the best fit for all systems. The behavior of competitive Cr(III)-Fe(III) biosorption were successfully described by the multicomponent Langmuir model, obtaining maximum capacities for Cr(III) and Fe(III) of 9.43 and 18.19 mg/g respectively. SEM/EDS results confirmed that the metals adsorb on the surface and FTIR identified the hydroxyl groups on the carboxylic acids as the active binding sites. © 2012 Elsevier Ltd. Source

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