Preparation, characterization and ion-exchange properties of a new 'organic-inorganic' composite cation exchanger polyaniline silicotitanate: Its applications for treatment of hazardous metal ions from waste solutions

摘要

Polyaniline silicotitanate an 'organic-inorganic' composite material, was prepared via sol-gel mixing of organic polymer polyaniline into the matrices of the inorganic precipitate of silicotitanate. The physico-chemical properties of this hybrid material were determined using atomic absorption spectrophotometry (AAS), CHN elemental analysis, ICP_S, X-ray (XRD and XRF), IR, TGA-DTA and scanning electron microscopy (SEM). The data obtained proposed that the chemical formula of polyaniline silicotitanate may be written as: [Ti4O9H7Si + (- C6H5NH-)] 4H2O. Ion-exchange capacity (EEC), thermal stability and distribution behavior, etc. were also carried out to understand the cation-exchange behavior of the material. On the basis of distribution studies, the material was found to be highly selective for Cs~+ and the selectivity sequence for sorption of Co~(2+), Cu~(+2), Cd~(2+), Cs~+ and Pb~(2+) ions on polyaniline silicotitanate was found to be; Cs~+> Pb~(2+)> Co~(2+)> Cu~(2+) > Cd~(+2). Thermodynamic parameters (i.e. △G°, △S° and △H°) have also been calculated for the adsorption of Co~(2+), Cu+2, Cd~(2+), Cs~+ and Pb~(2+) ions on polyaniline silicotitanate showing that the overall adsorption process is spontaneous and endothermic.