Adsorption properties of a nanostructured hybrid material containing aluminium towards some metal ions

Abstract

In the present work the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium was investigated. The novel organic-inorganic material was synthesized via a sol-gel method through hydrolysis and co-condensation reactions. Its structure was characterized by means of SEM, XRD and FTIR. Based on the data obtained the most probable cross-linking mechanism for the derived xerogel was proposed. The characterization of its texture parameters was carried out by low-temperature adsorption of nitrogen. The adsorption properties of this material with respect to Cu(II), Cr(III) and Pb(II) ions from single-component aqueous solutions and multi-component aqueous solutions containing also Cd(II) and Fe(III) were evaluated. The effect of contact time, acidity of initial solutions and metal ion concentrations was investigated using the batch method. Pseudo-first order, pseudo-second order and intraparticle diffusion models were used to analyze kinetic data. In all cases the adsorption was significantly affected by the pH value. Equilibrium modelling data were fitted to linear Langmuir, Freundlich and Dubinin-Radushkevich models. Best fit was observed for Langmuir model, which showed determination coefficients greater than 0.992 for all ions studied. The maximum adsorption capacities for single- and multi-component adsorption were calculated.

Biossorção passiva de cromo (VI) através da microalga Spirulina platensis

“…9 Diante da grande variedade de fontes geradoras de efluentes contendo cromo (VI), o desenvolvimento de novas tecnologias para remoção desse elemento vem sendo intensamente estudado. 10 Vários métodos vêm sendo utilizados para remoção de íons metálicos de soluções, tais como precipitação química, 11,12 troca iônica, 13 adsorção 14,15 e tratamento eletroquímico, 16 mas nem sempre são eficientes e apresentam-se com elevado custo, 17 principalmente quando aplicados a soluções diluídas de metais. 18 Portanto, a busca de novas tecnologias de tratamento desses efluentes que apresente vantagens em relação ao custo-benefício do processo vem direcionando ao aumento no interesse sobre o processo de biossorção, 17 que consiste na absorção de metais através de microrganismos ativos (biossorção ativa) ou inativos (biossorção passiva).…”

Physico‐Chemical Processes

“…Mahmudov and Huang (2011) Inorganic adsorbent. Detcheva et al (2011) investigated the adsorption of some transition metal ions from aqueous solutions on a silica-based nanostructured hybrid material modified by aluminium. The structure of the novel organic-inorganic material was characterized and the most probable cross-linking mechanism for the derived xerogel was proposed.…”