Surface modifications in polyampholytes: studies and applications

JUAN MANUEL LÁZARO MARTÍNEZ; LEAL DENIS MARÍA FLORENCIA; DENADAY, LR; GRACIELA YOLANDA BULDAIN; VIVIANA CAMPO DALL ORTO

Mainz, Alemania.

Simposio; Frontiers in Polymer Science ? International Symposium Celebrating the 50th Anniversary of the Journal Polymer; 2009

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There is a growing research interest on polymer-surfactant and polymer-metal ion mixtures due to their application in product formulations and selective oxidation of organic substrates with hydrogen peroxide, respectively [1,2]. We have recently syntethized a new polymeric material with amphoteric character denominated Poly(EGDE-MAA-2MI) and their copper(II) complexes, respectively [3-6]. The Cu(II)-polyampholyte acts as an heterogeneous catalyst for H2O2 activation and it has been employed for oxidative degradation of Methyl Orange, an azo-based dye [5]. The activation of the oxidant and the adsorption of the substrate were parallel processes that took place on the surface. The formation of hydroxyl radicals was evidenced by ESR. Combining an adequate ratio of mass of complex to solution volume with 25 mM [H2O2]0, an almost complete removal of the color was achieved between 10 and 20 min, in a neutral medium at room temperature with a minimal extension of adsorption to the catalytic surface. In absence of hydrogen peroxide the dye adsorbed on the polymer forming isolated aggregates evidenced by SEM. Fe(III)-complexes were tested for removal of organic pollutants such as bisphenol-A (BPA, an endocrine disrupting chemical) and textile dyes from water. They exhibited a fast step of adsorption to the surface of the particle, followed by a slower step of photo-catalytic oxidation or catalytic degradation by radical oxygen species. Polyampholyte complexes with anionic surfactants (SDS: sodium dodecyl sulfate and SDBS: sodium dodecylbenzenesulfonate) were used as solid-phase for extraction followed by analysis of BPA from food-simulating liquid in contact with baby-bottles. The new material was characterized by SEM, FTIR and solid-state 13C NMR. The adsorption of BPA followed first-order kinetics, and the isotherm obtained was H4-type [7] with a high affinity at levels below 0.1 mM.