Mathematical modeling for facilitated transport of Ge(IV) through supported liquid membrane containing Alamine 336

A mathematical model was developed for the germanium facilitated transport from a medium containing tartaric acid using Alamine 336 as a carrier. Modeling was carried out based on the extraction constant (Kext) obtained from the liquid-liquid extraction (LLX) modeling. The LLX data was achieved from experiments with conditions being Alamine 336 concentrations of 0.1-10 %v/v from a solution containing about 1.378 mmol/L Ge (100 mg/L) and tartaric acid as an anionic complexant. The LLX model was attained using the equilibrium-based procedure and fitted to extraction experimental data for various carrier concentrations. This model presented an accurate extraction constant (Kext=0.02) used in the facilitated transport modeling. The flat sheet supported liquid membrane (FSSLM) experiments were conducted in the condition of 1.378 mmol/L Ge (100 mg/L), tartaric acid concertation of 2.760 mmol/L, 1 M HCl as a stripping phase and various Alamine 336 concentrations in the range of 0 to 35 %v/v. The FSSLM model was developed according to the Fick’s law, the diffusional transport, and equilibrium equations. According to the model, mass transfer and diffusion coefficients for various concentrations of the carrier were found. In addition, the calculated and experimental values had a good correlation with together showing the validity of the model. This model can be used in the further process simulation such as hollow fiber SLMs.Peer ReviewedPostprint (author's final draft

Sistemas de formación ocupacional a distancia

En el artículo se aportan algunas ideas sobre la aplicación de las nuevas tecnologías de la información en la formación ocupacional a distancia a partir de los tres niveles generales de actuación de un sistema de formación ocupacional a distancia: nivel de producción, nivel de distribución y nivel de ejecución

Función de la vía de señalización WNT en la proliferación, diferenciación y transformación celular tiroidea

Tesis doctoral inédita, leída en la Universidad Autónoma de Madrid, Facultad de Medicina, Departamento de Bioquímica. Fecha de lectura: 15 de Marzo de 201

Promoción del autocuidado en el paciente alcohólico

Introducción: El alcohol es la droga más extendida en nuestro país, con elevada prevalencia y graves consecuencias para el paciente y su entorno. Los programas de educación con breves intervenciones, en el consumo excesivo de alcohol, sin llegar a la dependencia, han demostrado que reduce los riesgos de múltiples enfermedades y mejora el estado de salud, físico, mental y social del paciente. Objetivo: Determinar un plan de cuidados orientado a la educación sanitaria en un paciente alcohólico, dispuesto a recibir ayuda profesional. Material y Métodos: Elaboración de un plan de cuidados enfocado en un programa de educación distribuidos en doce sesiones, que nos ayude a la resolución de problemas de pacientes alcohólicos con disposición al cambio. Para ello, se ha realizado una valoración por los Dominios, usando la taxonomía NANDA, NOC y NIC, y los test específicos AUDIT y CAGE. Resultados: Evaluación del paciente tres meses después de desarrollo el programa de actividades de educación, se observa que, el paciente fue capaz de mejorar la comunicación familiar, expresar sentimientos, realizar técnicas de afrontamiento e identificar los beneficios y las consecuencias negativas del consumo de alcohol, pero el paciente encontró dificultad para llegar al nivel establecido en la eliminación del alcohol y desarrollar estrategias efectivas para el control del consumo. Discusión: Los profesionales de enfermería cuentan con la capacidad para intervenir en el tratamiento del alcoholismo, realizando educación y promoción de la salud, ayudando a mejorar el autocuidado del paciente. La entrevista motivacional es un aspecto fundamental para determinar qué tipo de intervención necesita el paciente, debemos evaluar durante todo el programa y analizar qué cambios se producen, y según estos actuar.Grado en Enfermerí

Germanium transport across supported liquid membrane with Cyanex 923: Mathematical modeling

A mathematical model was developed to monitor the facilitated transport of germanium(IV) from oxalic acid solutions through a flat sheet supported liquid membrane (FSSLM) containing four trialkylphosphine oxides (Cyanex 923). The FSSLM modeling was based on the extraction constant (Kext) calculated from the liquid-liquid extraction (LLX) modeling. The LLX model presented a reliable calculation of the extraction constant (Kex= 2.057×103 L/mol4). The FSSLM model was solved using Matlab® software according to extraction constant, Fick's law, and diffusional principles. The model predicts the overall mass transfer coefficient (Korg) to be 3.84 cm/s. Using this value, diffusion coefficients (Dm) for various Cyanex 923 concentrations of 0.126, 0.252, 0.378, 0.505, 0.631 and 0.757 mol/L are found to be 8.50×10-4, 4.30×10-4, 1.87×10-4, 5.87×10-5, 2.57×10-5, 2.09×10-5 cm2/s, respectively. The results show that the diffusion rate of the current study is approximately more than that of similar FSSLM systems containing Cyanex 923 used to transport various metals. The modeling values are in good agreement with the experimental data, showing the good reliability of the mathematical model.Peer ReviewedPostprint (author's final draft

Recent advances in smart integrated membrane assisted liquid extraction technology

Novel processes based on SIMALE have been proposed as effective methods for the selective separation of different chemical species such as metal ions, organic/biologically important compounds and gas mixtures from different waste streams including nuclear waste. The industrial use of supported liquid membranes based on conventional liquids is limited by their relative instability and short lifetime. Under SIMALE techniques, the stability of the SLM is ensured by a modified SLM with pseudo emulsion based hollow fiber strip dispersion or non-dispersive solvent extraction techniques. In order to promote operational stability, SIMALE, using ionic liquids, as a liquid membrane phase could overcome these inconveniences due to their negligible vapour pressure and the possibility of minimizing their solubility in the surrounding phases. SIMALE studies on membrane-based dense gas extraction reported higher extraction efficiencies when the near critical or supercritical solvent is used. This review also discuss important applications including scale up, process intensification aspects, current status of the technology and future directions.Peer ReviewedPostprint (author's final draft

Response surface methodology based on central composite design for simultaneous adsorption of rare earth elements using nanoporous calcium alginate/carboxymethyl chitosan microbiocomposite powder containing Ni0.2Zn0.2Fe2.6O4 magnetic nanoparticles: Batch and column studies

In this research paper, the utilization of the magnetic calcium alginate/carboxymethyl chitosan/Ni0.2Zn0.2Fe2.6O4 (CA/CMC/Ni0.2Zn0.2Fe2.6O4) was investigated for the simultaneous aqueous adsorption of Nd (III), Tb (III), and Dy (III). The magnetic products were characterized by FE-SEM, EDX, XRD, FT-IR, TGA, and VSM techniques. The saturation magnetization value for Ni0.2Zn0.2Fe2.6O4 and CA/CMC/Ni0.2Zn0.2Fe2.6O4 was found to be 45.87 and 14.14 emu/g, respectively. Using RSM, a quadratic polynomial equation was obtained to predict the adsorption efficiency of each ion. Under the conditions of pH = 5.5, adsorbent dosage of 0.1 g, initial concentration of 30 mg/L, and contact time of 53 min predicted by RSM, the adsorption efficiencies of Nd (III), Tb (III), and Dy (III) were respectively 95.72, 96.17, and 99.44%. The isotherm and kinetic data were respectively fitted well with Freundlich and pseudo-second-order (PSO) models. The desorption of the loaded ions was effectively carried out by 0.2 M HNO3, and the adsorbent was consecutively utilized with 2.54, 1.63, and 1.16% decrease in adsorption efficiency for Nd (III), Tb (III), and Dy (III), respectively, after the forth cycle. Additionally, the adsorption behavior of the CA/CMC/Ni0.2Zn0.2Fe2.6O4 towards Nd (III), Tb (III), and Dy (III) was studied by using a fixed-bed column technique.This work has been supported by the Spanish Ministry of Economy and Competitiveness (Ref. CTM2017-83581-R). Hamedreza Javadian acknowledges the financial support received (Ref. BES-2015-072506).Peer ReviewedPreprin

Neodymium recovery by chitosan/iron(III) hydroxide [ChiFer(III)] sorbent material: Batch and column systems

A low cost composite material was synthesized for neodymium recovery from dilute aqueous solutions. The in-situ production of the composite containing chitosan and iron(III) hydroxide (ChiFer(III)) was improved and the results were compared with raw chitosan particles. The sorbent was characterized using Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy-energy dispersive X-ray analyses (SEM-EDX). The equilibrium studies were performed using firstly a batch system, and secondly a continuous system. The sorption isotherms were fitted with the Langmuir, Freundlich, and Sips models; experimental data was better described with the Langmuir equation and the maximum sorption capacity was 13.8 mg g-1 at pH 4. The introduction of iron into the biopolymer matrix increases by four times the sorption uptake of the chitosan; the individual sorption capacity of iron (into the composite) was calculated as 30.9 mg Nd/g Fe. The experimental results of the columns were fitted adequately using the Thomas model. As an approach to Nd-Fe-B permanent magnets effluents, a synthetic dilute effluent was simulated at pH 4, in order to evaluate the selectivity of the sorbent material; the overshooting of boron in the column system confirmed the higher selectivity toward neodymium ions. The elution step was carried out using MilliQ-water with the pH set to 3.5 (dilute HCl solution).Peer ReviewedPostprint (published version

Transport of Zn(II), Fe(II), Fe(III) across polymer inclusion membranes (PIM) and flat sheet supported liquid membranes (SLM) containing phosphonium ionic liquids as metal ion carriers

This is an Accepted Manuscript of an article published by Taylor & Francis Group in Separation Science and Technology on 18/04/2016, available online: http://www.tandfonline.com/doi/full/10.1080/01496395.2016.1174265In this work transport of Zn(II), Fe(II) and Fe(III) ions from chloride aqueous solutions across polymer inclusion membranes (PIMs) and supported liquid membranes (SLMs) containing one of three phosphonium ionic liquids: trihexyl(tetradecyl)phosphonium chloride (Cyphos IL 101), trihexyl(tetradecyl)phosphonium bis(2,4,4-trimethylpentyl)phosphinate (Cyphos IL 104) and tributyl(tetradecyl)phosphonium chloride (Cyphos IL 167) as an ion carrier was reported. The results show that Zn(II) and Fe(III) are effectively transported through PIMs and SLMs, while Fe(II) transport is not effective. The highest values of initial flux and permeability coefficient of Zn(II) were noticed for SLM containing Cyphos IL 167. Cyphos IL 101-containing SLM is more stable than PIM.Peer ReviewedPostprint (author's final draft