Preparation and characterization of polymeric microspheres for Cr(VI) extraction

Microspheres (MS) from different polymers were prepared using two routes. Route A: process of phase inversion with solutions of polysulfone (PSf) in dichloromethane (DCM) and polyvinylpyrrolidone (PVP) as additive. Different weight ratios of PSf-PVP were used in the MS preparation. Route B: MS were obtained by cross-linking in emulsion using a commercial silicone as raw material. The obtained MS were analysed according to their morphological-structural characteristics and in relation to their Cr(VI) extraction capacity using impregnated MS with Aliquat 336. The results obtained showed that MS prepared with PSf-PVP have both less specific surfaces and relative porosities when the proportion of PVP in the mixture is increased. Extraction tests of ion Cr(VI) indicated that synthesized MS have adequate structural characteristics and interesting adsorptive properties which give rise to impregnating selective extractants. Impregnated microspheres with Aliquat 336 prepared from 2:1 PSf-PVP ratio achieved the highest Cr(VI) extractive performance (92% of Cr extraction for contact time of 60 min) and the best breakthrough point in column tests (up to 10 h in the first cycle).Fil: Ochoa, Nelio Ariel. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Illanes, Cristian Omar. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Marchese, Jose. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis; ArgentinaFil: Basualto, C.. Universidad de Chile; ChileFil: Valenzuela, Fernando R.. Universidad de Chile; Chil

One-Step Synthesis of CaO-ZnO Efficient Catalyst for Biodiesel Production

Biodiesel is the best candidate for fuel oil replacement, and to obtain it, heterogeneous catalysts offer large advantages: they can be separated from the product and reused. This work reviews a novel one-step synthesis of CaO-ZnO catalytic particles suitable for biodiesel production. The catalyst is synthesized using an original simple method that involves mixing of ZnO with CaCO3 and subsequent calcination. The CaO-ZnO microparticles obtained present an average size of 2 μm. This material shows the characteristic crystallographic cubic structure of CaO and the hexagonal phase of ZnO. The temperature-programmed reduction experiment evidences an interaction between CaO and ZnO. Moreover, the infrared spectroscopy shows typical bands of these compounds. The catalyst shows high biodiesel yield, up to 73% in the first cycle and 64% in the second one. In this work, the synthesis of an efficient CaO-ZnO catalyst with a huge potential is revealed, which could be an economic alternative to produce biodiesel.Fil: Toledo Arana, Javier Marcelo. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Torres, Juan Jose. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Acevedo, Diego Fernando. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; ArgentinaFil: Illanes, Cristian Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Ochoa, Nelio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Pagliero, Cecilia Liliana. Universidad Nacional de Río Cuarto. Facultad de Ciencias Exactas Fisicoquímicas y Naturales. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Investigaciones en Tecnologías Energéticas y Materiales Avanzados; Argentin

Review of the characterization of sodium alginate by intrinsic viscosity measurements: Comparative analysis between conventional and single point methods

In the pharmaceutical and food industry, alginate is used in aqueous solutions and excipients as thickener, gelling agent, coagulant and encapsulant. This biopolymer is very important, with many key industrial applications, especially if the intrinsic viscosity [η] and the viscometric molecular weight (Mv) are known. Alginate is obtained from the cell walls of algae such as Macrocystis pyrifera, Laminaria hyperborea, Laminaria digitata, Laminaria japonica, Sargassum vulgare, etc.; bacteria such as Pseudomonas aeruginosa and Azotobacter vinelandii can also synthesize it. This work studied alginate in aqueous solution from 0.25 to 1% wt., measuring its intrinsic viscosity in order to obtain its Mv. The intrinsic viscosity is calculated by the classical methods of Huggins, Kremer, Schulz-Blashke and Martin. We compared several single point methods to determine which of them would be more appropriate for an alginate-water system. We also obtained Mark-Houwink parameters and the corresponding viscometric molecular weight.Fil: Masuelli, Martin Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Illanes, Cristian Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin

Removal and recovery of Cr (III) with emulsion liquid membranes

This work is an experimental study of the removal and recovery of Cr(III) ion from aqueous solutions using the emulsion liquid membrane (ELM) technique. The ELM is a solution of di(2-ethylhexyl) phosphoric acid (D2EHPA) in kerosene as carrier and sorbitan monooleate SPAN 80 as surfactant. The transport capacity of the metallic ion in the ELM and the best conditions of the feed and stripping solutions in batch tests were determined. The results obtained show a good yield in Cr(III) recovery reaching 100% in a relatively short period of time (30 min) with the following operational conditions: feed solution of Cr(III) pH = 4, stripping solution of 5 mol L-1 sulfuric acid or 1 mol L-1 ammonium persulphate, and an ELM made up of 1 mol L-1 D2EHPA in kerosene; 4% (w/w) paraffin and 2% (w/w) SPAN 80.Fil: Acosta, Alfredo Orlando. Universidad Nacional de San Luis. Facultad de Ciencias Fisico Matematicas y Naturales. Departamento de Fisica. Laboratorio de Ciencias de Superficies y Medios Porosos; ArgentinaFil: Illanes, Cristian Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Marchese, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin

Kinetic sorption of Cr(VI) into solvent impregnated porous microspheres

The sorption rates of Cr(VI) ion from acid chromate solutions with Aliquat 336 impregnated microspheres (MS) were examined. MS of polysulfone (PSf) and poly(styrene-acrylenitrile) (SAN) were prepared by phase inversion process. The MS obtained have different size and morphology. The sorption behavior and the rate-controlling sorption step have been discussed from the Elovich equation, pseudo-second order and Crank kinetic models. Even all models gave satisfactory correlations with the experimental data, the Crank model showed to be more realistic and appropriate to interpret the Cr(VI) kinetic sorption results. These analysis indicate that the intraparticle solute diffusion is the rate-controlling sorption step, and suggest that there is a surface diffusion contribution to the overall Cr(VI) mass transport inside the MS which is more important as the MS pore size decreases.Fil: Illanes, Cristian Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Ochoa, Nelio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Marchese, Jose. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin

Evidence of structural changes of an enzymatic extract entrapped into alginate beads

In this work, we analyzed the structural changes of araujiain entrapped into alginate beads. Araujiain is an enzymatic preparation containing three known enzymatic fractions with each fraction individually presenting a similar catalytic performance. Fluorescence and infrared spectroscopy, thermal analysis and residual catalytic activity studies were carried out. A small red shift in the spectrum of araujiain was observed after the entrapment process. Changes in the polarity around the tryptophan (Trp) residues were associated with an enzyme conformational change. From the Fourier transform infrared spectroscopy (FTIR) analysis, it was demonstrated that interactions between the enzyme extract and Ca alginate caused different structural behavior in araujiain. According to the diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) study, it was possible to conclude that a secondary structure with a high α-helical character was responsible for the highest activity of entrapped araujiain. Finally, from thermal analysis measurements, it was proved that entrapment of araujiain augments the thermal stability of both the enzyme extract and Ca alginate, indicating a possible interaction between enzyme extract and its support.Fil: Illanes, Cristian Omar. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Quiroga, Evelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; ArgentinaFil: Camí, Gerardo Enrique. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Investigaciones en Tecnología Química. Universidad Nacional de San Luis. Facultad de Química, Bioquímica y Farmacia. Instituto de Investigaciones en Tecnología Química; ArgentinaFil: Ochoa, Nelio Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Luis. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich". Universidad Nacional de San Luis. Facultad de Ciencias Físico Matemáticas y Naturales. Instituto de Física Aplicada "Dr. Jorge Andrés Zgrablich"; Argentin