Estudio de adsorción de plomo utilizando quitosano modificado con hierro.
The lead is a great polluting agent for environment, for this, the necessity to look for treatments that help to resist the lead concentrations was taken, avoiding to cause diseases to the alive beings that inhabit it. The process that we used is the adsorption through a bio polymer called chitosan,...
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| Định dạng: | bachelorThesis |
| Được phát hành: |
2017
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| Những chủ đề: | |
| Truy cập trực tuyến: | http://repositorio.utmachala.edu.ec/handle/48000/11414 |
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Thêm thẻ | Tóm tắt: | The lead is a great polluting agent for environment, for this, the necessity to look for treatments that help to resist the lead concentrations was taken, avoiding to cause diseases to the alive beings that inhabit it. The process that we used is the adsorption through a bio polymer called chitosan, obtained from shrimp exoskeleton whose properties help us to turn and modify them in pearls of nanoparticles and come to the aid of increasing the percentage of adsorption of metallic ions of the lead. In addition, this technique has low cost, very efficient and friendly-environment advantages, the bio polymer is used in many industries like agriculture, pharmaceutics, nourishing and in the cosmetic elaboration like lipsticks. The objective of this project of investigation was to adsorb lead through chitosan pearls-modified with iron (ChiFer (III)), determining its capacity and speed of adsorption. It was used bio polymer donated by the Grupo de Técnicas de Separación y Tratamientos de Residuos Industriales (SETRI) of the Universidad Politécnica de Cataluña. In order to make the adsorption study and determine the field in where a greater percentage of lead adsorption takes place, firstly, it was come to make an analysis of pH, with lead solutions at a concentration of 50 ppm at different pH (2-3-4-5-6) for a period of 48 hours at 200 rpm by adding 20 mg chifer chitosan (III). It should be noted that in solutions containing acidic pH level, will occur the protonation of the chelating groups of the adsorbent, and in the alkaline medium occurs the precipitation of metals, when the pH level was determined, the construction of the curves of isotherms and kinetics would have been proceeded. For the adjustments of the experimental data of the equilibrium isotherms, it was bibliographically reviewed that there are mathematical models such as Langmuir and Freundlich, and for the kinetic data, It was adjusted to the pseudo first and second order models, determining which is the dominant system. Adsorption capacities of lead by chitosan ChiFer (III) at pH 5 gave 90% adsorption of lead. Study experiments were performed with pH solutions from pH 1 to pH 6; after 24 hours it was observed that in the samples of pH 1, 2, 3 and 6 the chitosan pearls were solubilized, becoming yellowish by the presence of iron. Adsorption occurred at pH 4, 5 and 6. The result of the pH study was adjusted to pH 5 resulting 90% adsorption of lead. The study of isotherms results indicated that the adsorption capacity of lead applying chitosan pearls- modified with iron is 85.6 mg g-1 giving experimental data, and the experimental data were adjusted to the Langmuir and Freundlich adsorption models. These adjustments were evaluated using the correlation coefficient, linear adjustments indicate that the experimental data correlate better with the Langmuir model, with R2 = 0.985. The kinetic experimental data were fitted to the mathematical model of pseudo second order, as can be observed in figure 8, with a high correlation coefficient (R2 of 0.998). |
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