Examinando por Materia "QUITOSANO"
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Capítulo de libro Chitosan: from organic pollutants to high-value polymeric materials(2017) Errea, María Inés; Rossi, Ezequiel; Goyanes, Silvia Nair; D'Accorso, Norma Beatriz"...chitosan has proved to be versatile for so many industrial applications and its versatility is the main value of this polymer. However, the lability at acidic pH of chitosan is a limiting factor that affects mainly its industrial implementation for the removal of metallic anions from water. In addition, the physical and mechanical properties may vary between two manufacturing batches due to the characteristic polydispersity of chitosan with respect to molecular weight and degree of acetylation. This variation could affect the industrial process and in some cases, when strict specifications are requested (e.g., drug delivery), increase the final cost of the product because a purification step prior to use is required. Briefly, despite of the disadvantages mentioned before, due to its great versatility, its nontoxicity, its biodegradability, and the fact that it has a renewable resource, the industrial interest in chitosan and its application has been increasing remarkably in the last years."Artículo de Publicación Periódica Preparation of an environmentally friendly lead adsorbent. A contribution to the rational design of heavy metal adsorbents(2020-10) Rossi, Ezequiel; Ávila Ramírez, Jhon Alejandro; Errea, María Inés"This work described the preparation and characterization of water insoluble chitosan derivatives as lead adsorbents. In highly regioselective reactions, N-substituted crosslinked chitosan derivatives were obtained by crosslinking native chitosan with mucic and adipic acid (a polyhydroxylated and a non-functionalized diacid of the same length chains). The crosslinking degree of the chitosan modified with adipic acid was significantly higher than that crosslinked with mucic acid (0.446 and 0.316, respectively), while the degree of substitution was almost the same (approximately 80 %). Lead adsorption isotherms were constructed at different temperatures and adjusted to well-known models, obtaining the best fit to the experimental data with Langmuir model. The lead adsorption capacity of new materials was greater than many of the adsorbents described in literature (76.3 and 69.7 mg g−1 for chitosan modified with mucic and adipic acid, respectively). Moreover, thermodynamic parameters were calculated, and results showed that the lead adsorption on the derivatives was spontaneous, exothermic, and governed by chemical interaction. Besides, kinetic studies were performed and adjusted to well-known models. The pseudo-second order kinetic equation was the one that most appropriately described the lead adsorption on the new materials. Results were consistent with the strong electrostatic attraction established between the lead cations and the free carboxylate groups of the derivatives."