488 research outputs found
Development of an integrated biological base processes for the recovery of strategic metals from electronic waste
Pòster amb el resum gràfic de la tesi doctoral en curs, que forma part de l'exposició "Doctorat en Recursos Naturals i Medi Ambient de la UPC Manresa. 30 anys formant en recerca a la Catalunya Central 1992-2022".Project BIOMETAL PID2020- 117520RA-I00 and ACCIÓ BIOCOLI ACE 34/21/000044,Postprint (published version
Separation of tripeptides in binary mixtures using ion-exchange membrane adsorber
The adsorption of three tripeptides in an ion-exchange membrane adsorber was analyzed in single and binary solutions, with the aim of evaluating the capability of the membrane adsorber to separate triglycine (GGG) from two other tripeptides: glycine-histidine-glycine (GHG) and glycine-tyrosine-glycine (GTG). The equilibrium adsorption of single peptide solutions followed the Langmuir isotherm and GTG showed the highest adsorption affinity. The dynamic adsorption was fitted with a generalized model, which was defined using dimensionless parameters and based on the continuity equation. In general, the calculated and experimental breakthrough curves were correlated with high agreement. It was found that the axial dispersion coefficient was independent of the peptide molecule and that it increased with flow rate. The competitive adsorption between peptides in binary solutions was analyzed using the extended and modified Langmuir equations. The adsorption equilibrium data were satisfactorily fitted with the modified Langmuir isotherm for GGG/GHG solutions, while the extended Langmuir isotherm was a better fit to the data for GGG/GTG solutions. The experimental breakthrough curves of the two peptide binary mixtures were simulated using the parameters calculated from the competitive isotherms and the parameters obtained from the breakthrough curves of the single peptide solutions. The separation of GGG from the GGG/GHG mixtures was possible. The GGG recovery was higher than 35% and the GGG molar fraction in the outlet stream was higher than 0.994
Influence of chemical speciation on the separation of metal ions from chelating agents by nanofiltration membranes
The simultaneous separation of various metal ions (nickel, copper, calcium, and iron) from chelating agents (EDTA and citric acid in water streams using Nanofiltration membranes is analyzed. Assuming that multiply-charged species are highly rejected, chemical speciation com-10 putations reproduce the observed patterns of metal and ligand rejection at different pH values and concentrations.Postprint (updated version
Síndrome de estar quemado por el trabajo
El objetivo del presente trabajo es sintetizar los últimos pronunciamientos de los Tribunales de Justicia sobre el síndrome de desgaste profesional (desde la entrada en vigor de la actual Ley 31/1995
hasta nuestros días) para fomentar su prevención en la realidad actual de nuestro tejido empresarial. Se analizarán aspectos como la base jurisprudencial y la catalogación del síndrome y se intentará dar respuesta a la siguiente pregunta: ¿existe base jurisprudencial para catalogar el burnout como accidente de trabajo ante la “imposibilidad actual”
de ser considerado enfermedad profesional
Influence of pH and NaCl on the rejection of glycine and triglycine in binary solutions for desalination with diananofiltration
Nanofiltration can be used as the last step in the purification of the biomolecules that are present in many industrial by-products, such as biological protein hydrolysates. The present study explored the variation in glycine and triglycine rejections in binary solutions with NaCl at different feed pHs with two nanofiltration membranes: MPF-36 and Desal 5DK with molecular weight cut-offs of 1000 and 200 g·mol-1, respectively. First, water permeability coefficient showed a n-shaped curve with feed pH, which was more evident for the MPF-36 membrane. Second, membrane performance with single solutions was studied and the experimental data were fitted with the Donnan steric pore model with dielectric exclusion (DSPM-DE) to explain the variations of solute rejection with feed pHs. Glucose rejection was assessed to estimate the membrane pore radius of the MPF-36 membrane, and a pH dependence was observed. For a tight membrane (Desal 5DK), glucose rejection was close to unity and the membrane pore radius was estimated from the glycine rejection in the feed pH range from 3.7 to 8.4. Glycine and triglycine rejections showed a pH-dependence with a u-shaped curve, even for the zwitterion species. In binary solutions, glycine and triglycine rejections decreased with NaCl concentration, especially in the MPF-36 membrane. Triglycine rejection was always higher than NaCl rejection and it was estimated that triglycine can be desalted using a continuous diananofiltration the Desal 5DK membrane
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