Estudo da imobilização do ácido tânico (AT) em espumas de poliuretano de origem vegetal (PU) para adsorção de íons Cu2+ e Zn2+ em meio aquoso

• Autor(a) principal: Rodrigues, Aline Vieira
• Data de Publicação: 2015
• Tipo de documento: Dissertação
• Idioma: por
• Título da fonte: Repositório Institucional da UFMT
• Texto Completo: http://ri.ufmt.br/handle/1/1578
• topic: Ácido tânico; Adsorção; Poliuretano; Cu 2+, Zn 2+; CNPQ::CIENCIAS EXATAS E DA TERRA::QUIMICA; Tannic acid; Adsorption; Polyurethane; Cu 2 2+, Zn 2+

The combination of different types of materials has been studied for improvement and acquisition of new properties, among the possible applications should be noted the use of adsorption systems for the removal of toxic metal ions and other pollutants in wastewater, thus enabling the it’s reuse. Some polymers, especially foams of polyurethanes (PUs) have been studied as adsorption systems, but not with satisfactory results for this purpose. In order to optimize the use of PUs, tannic acid (TA) immobilized on the PU was used, considering that the AT is a natural polyphenols present in the vegetable kingdom and has properties in its structure capable of complexion metals and macromolecules due to the presence groups for catechol’s. The objective of this study was to evaluate the ability of AT assets in PUs foams of plant origin (P-AT) adsorb on the metal ions Cu 2+ and Zn 2+ in aqueous system. For the preparation of the UP-AT system, PUs were immersed in aqueous solutions of AT 0.01 mol L-1 at different pH values (5, 7, 8 and 10) and contact times. PH changes, contact time and concentration of AT in the aqueous solution used, suggest hydrogen bonds and ion-dipole interactions with AT PU, encouraging restraint and efficiency of this system. The adsorption study ion Cu 2+ indicated partial desorption of AT immobilized on PU, due to the strong chemical interaction between Cu 2+ ions and AT. The removal of metal ions from the aqueous solution, fixed adsorbent mass quantity was equal to 0% (Co = 20 mg L-1) and 38% (Co = 1000 mg L-1 ) for Cu 2+ ions and 50% (Co = 20 mg L-1 ) and 25% (Co = 1000 mg L-1 ) for Zn 2+ ion, indicating that the adsorbent of the adsorption capacity increases linearly with the concentration of metal ions. The metal ions of adsorption isotherms suggested that the adsorption of metal ions in PU-AT's occur in multi-sites and the PU-AT systems have heterogeneous surfaces. The thermal characterizations confirmed the detention of the AT in PUs, as well as evaluate its thermal behavior. The PU-AT system can be used as a method for the pretreatment WTPs and STPs in cases where there are high concentrations of metal ion in view of its low efficiency in concentrations below 50 mg L-1, where the Cu 2+ ions and 20 mg L-1 , where the Zn 2+ ions.