Nanofiltration of glucose: Analysis of parameters and membrane characterization

Membrane characterization and modeling of nanofiltration processes of uncharged solutes are of special interest for the food industry. In this work two commercial membranes, DK and DL, were used to concentrate glucose solutions. Membranes were characterized according hydrophobicity, thickness, porosity, and hydraulic permeability. The influence of pressure and concentration of glucose on the permeate flux and rejection were studied. Both membranes presented a great potential for the food industry due to their high rejection of glucose. The osmotic pressure model was combined with film theory and the real driven force was calculated taking into account the osmotic pressure and the concentration polarization. Both phenomena influenced the process (concentration polarization only in the most dilute solutions at low pressure) and the permeability for glucose solutions was similar to the hydraulic permeability. A mathematical model based on the Donnan-Steric Pore Model was used to determine the pore radius and the effective thickness of both membranes. As the concentration inside the pore (needed for the calculations) is difficult to measure experimentally, various alternatives were proposed. The average of the concentration at the interface and permeate best fitted the experimental data. The model was applied successfully; the maximum error was 8% within the range of concentrations (5–100 g/L) for the DL membrane and 5% for the DK membrane up to 50 g/L.Fil: Almazán, Jorge Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Romero Dondiz, Estela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Castro Vidaurre, Elza Fani. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; Argentin

Comparison of the performance of ultrafiltration and nanofiltration membranes for recovery and recycle of tannins in the leather industry

The tanning industries are characterized by generating large volumes of wastewater. The largest volume of effluents comes from the tanning stage and has a high concentration of tannins and a low ratio tannin/non-tannin (T/NT). Membrane processes are appropriate technologies for treating these effluents. The aim of this study was to evaluate the performance of polymeric membranes in the treatment of exhausted vegetable tannin liquor from a tanning industry for its reuse. Different ultrafiltration (UF) and nanofiltration (NF) membranes were tested. Permeate flux decline, fouling resistances, fouling index, rejection for tannin (T) and non-tannin (NT) and increasing of the T/NT ratio in the retentate stream were evaluated. NF membranes had better characteristics than those of UF. The MPF-34 membrane showed the best separation properties with an increasing of the T/NT ratio from 1.68 to 1.80, for a volume reduction factor of 1.04. DK presented the best permeation properties and the lowest fouling, with an average permeate flux of 17.17 L/(m2 h) and a fouling index (If) of 27.3%. The results were promising, so this clean technology could be implemented to minimize the negative environmental impact caused by tanning industry.Fil: Romero Dondiz, Estela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Almazán, Jorge Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; ArgentinaFil: Castro Vidaurre, Elza Fani. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones para la Industria Química; Argentin

Removal of vegetable tannins to recover water in the leather industry by ultrafiltration polymeric membranes

The leather tanning industry consumes large amounts of water and produces, consequently, significant volumes of wastewater with high concentration of chemicals and organic matter. One of the main chemicals present in effluents is the vegetable tannin, which causes a severe environmental impact. With the aim of predicting the performance in chemicals separation of two ultrafiltration (UF) polymeric membranes (OT050 and GR60PP) for potential use in the purification of the waste stream of vegetable tanning liquors, a synthetic wastewater was prepared. Trials were carried out at laboratory scale using a flat cell with an effective area of 0.004m2. The effect of transmembrane pressure in the permeate flux was studied. Flux decline, fouling resistance and fouling index of the membranes were analyzed. The efficiency of different membranes was assessed using the rejection coefficient for tannins, non-tannins and total solids. Analysis of the wastewater treated by UF showed 83% of tannin retention and a recovery of the water flux after cleaning the membrane GR60PP with water of 41-45%. The rejection coefficient observed for the GR60PP membrane was higher than for the OT050. There are no previous studies related to the removal of vegetable tannins in exhausted vegetable tanning bath by using UF polymeric membranes. This study sets a precedent because the results obtained are very promising regarding permeate flux and rejection observed.Fil: Romero Dondiz, Estela María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Almazán, Jorge Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Rajal, Verónica Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; ArgentinaFil: Castro Vidaurre, Elza Fani. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Salta. Instituto de Investigaciones Para la Industria Química. Universidad Nacional de Salta. Facultad de Ingeniería. Instituto de Investigaciones Para la Industria Química; Argentin