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Type: Artigo de periódico
Title: Calorimetric investigation of metal ion adsorption on 3-glycidoxypropyltrimethylsiloxane plus propane-1,3-diamine immobilized on silica gel
Author: Sales, JAA
Airoldi, C
Abstract: The silylant precursor agent 3-glycidoxypropyltrimethoxysilane was covalently anchored onto a silica gel surface followed by propane-1,3-diamine molecule incorporation using a heterogeneous route (SiHT). On another series, the precursor agent was previously reacted with diamine to give the silylant agent in homogeneous condition, before immobilization (SiHM). The degrees of immobilization were 0.80 and 1.53 mmol g(-1) for SiHT and SiHM, respectively. Both grafting surfaces were employed to extract the divalent cations nickel, copper, cobalt and zinc from aqueous solutions. This cation/nitrogen interactive process was calorimetrically followed to give exothermic enthalpy, negative free Gibbs energy and positive entropy values. These favorable thermodynamic data are more pronounced for copper on both surfaces, with a higher tendency for SiHM, due to the larger amount of available nitrogen atoms in the pendant chain covalently attached to the inorganic silica backbone. (C) 2004 Elsevier B.V. All rights reserved.
Subject: silica
Country: Holanda
Editor: Elsevier Science Bv
Citation: Thermochimica Acta. Elsevier Science Bv, v. 427, n. 41671, n. 77, n. 83, 2005.
Rights: fechado
Identifier DOI: 10.1016/j.tca.2004.08.015
Date Issue: 2005
Appears in Collections:Unicamp - Artigos e Outros Documentos

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