The performance of novel chitosan-poly(vinyl alcohol) gel beads was evaluated removing lead, cadmium and chromium from mining-influenced groundwater (MIGW) under hydrodynamic conditions employing column sorption experiments. To elicit the efficiency of the synthesized materials, the sorbent bed height within the packed column and volumetric flow were varied; the column configuration was changed using packed and fluidized arrangements. The fluidized bed configuration presented higher sorption efficiency for Pb, Cd and Cr ions than the fixed bed configuration: 78%, 52% and 62% against 60%, 35% and 37%. The packed bed data were processed using the Clark, Dose-Response, Yoon-Nelson and Woldborska models. The best fitting was obtained with the Dose-Response model. The experimental output confirmed the effective reduction of the harmful metals in MIGW at a very short breakthrough time from 3 to 15 min, which is strategic due to the global effects on both human health and environment.

There is a great problem for the supply of drinking water in Mexico, the state of Zacatecas is no exception, in addition to this the water in the region has the presence of heavy metals, fluorine compounds, arsenic and high hardness. The objective of this work is to remove the arsenic present in the drinking water of the municipality of Ojocaliente, Zac. using chitosan gel beads. The initial sample was characterized giving an As concentration of 70 ppb, a high value in reference to the Official Mexican Standard NOM-127-SSA1-1994 for water for human consumption. A series of experiments were carried out at different concentrations, using drinking water sampled in Ojocaliente, Zac., The operation was in batches at an average temperature of 19 ° C and 250 rpm, in aliquots of 50 ml and 0.3 g of gel chitosan beads. The isotherm and kinetics model that fit the data was determined, being Langmuir and Pseudo first order, respectively, and 20% of the arsenic present in the water was removed in a separation step.

El objetivo de la presente investigación es evaluar la absorción de CO 2 en una solución acuosa de quitosano y líquidos iónicos. Para alcanzar el objetivo propuesto, se preparan soluciones acuosas de MEA a 30%, con quitosano a 0.5% y 3.0%, además se elaboran soluciones de quitosano con líquidos iónicos, como son; el bromuro de 1-hexil-3-metilimidazolio; líquido iónico eutéctico con y sin Li 2 O; y Bromuro de 1-etil-3-metilimidazolio. La experimentación se realiza en una celda de acero inoxidable donde se coloca el absorbente y una corriente directa de gas, ambas se mezclan a 300 rpm y temperatura de 30 °C hasta alcanzar el equilibrio. Además, para que la evaluación sea eficiente se modifica la presión (1 a 6 atm) y la concentración del quitosano en la solución, para determinar la capacidad de absorción del CO 2. Al analizar los resultados se encuentra que de las soluciones preparadas la absorbe una mayor cantidad de CO 2 es la de 0.5% de quitosano, sin embargo la velocidad de absorción es lenta. También se observa que la capacidad de absorción de las soluciones se incrementa con la presión. Por último, la propiedad con mayor efecto en la transferencia de masa es la viscosidad. Se puede concluir que la eficiencia en la capacidad de absorción aumenta conforme disminuye la cantidad de quitosano en las soluciones. Además que, las soluciones de quitosano a 3% y 0.5% muestran una mejor capacidad de absorción que los líquidos iónicos. La máxima capacidad de absorción que se obtuvo en líquidos iónicos fue para el caso del eutéctico a 30% y 3 atm. El valor de pKa del ácido del anión del líquido iónico, juega un papel importante en la capacidad de absorción de CO 2 , a mayor valor de pKa, mayor capacidad de captura. Descriptores: Dióxido de carbono, quitosano, líquidos iónicos.

The objective of this work is to study the process of phosphatizing with manganese by immersion. In the literature there is not enough information on the phosphate process with manganese phosphate, hence the main contribution of the present. The methodology involves an electrochemical study, using open circuit potential techniques in order to follow the kinetics of the process. In the same way, the characterization of the coating formed on the surface of each steel used was carried out using scanning electron microscopy and X-ray energy dispersion spectroscopy. Through this technique, the time was found in which the internal layer of the coating developed on the phosphatized substrates, both on the rough and the rough sides of the steel samples. The results obtained show that the formation of the manganese phosphate coating on the steels depends both on the grain size of the steels at the beginning of the process, as well as on the surface finish to which the steel surface is subjected, resulting in an increase in the size of the crystals, and affecting the rate of disintegration and growth of the same.