Adsorption of As (III) by using polythiophene/Fe_2 o_3 nanocomposites synthesized in aqueous/non-aqueous media

Polythiophene (PTh) and its nanocomposites were successfully synthesized by the in situ chemical oxidative polymerization method in the presence of ferric chloride as an oxidant and poly (vinyl pyrrolidone) as surfactant in aqueous/non-aqueous media. The adsorbents were characterized in terms of, morphology and chemical structure by different techniques such as FT-IR, SEM and XRD. The scanning electron micrographs of polythiophene and its nanocomposites prepared in aqueous/non-aqueous media showed differences in the surface morphologies in the presence poly (vinyl pyrrolidone) and &gamma-Fe_2 O_3 nanoparticles. The FTIR spectra showed that the intensity of peaks was related to the type of surfactant. The crystalline natures of nanocomposites were determined by XRD analysis. The extra peaks in the XRD pattern of nanocomposites indicate the presence of &gamma-Fe_2 O_3 nanoparticles in the polythiophene matrix. The aim of this research was to investigate the sorption characteristic of polythiophene and its nanocomposites for the removal of As (III) from aqueous solution. The presence of surfactants leads to improve the adsorption of As (III) by changing the surface morphology of polythiophene/Fe2O3 nanocomposites. The removal percentage of As (III) was carried out by using batch process mode. The adsorption of As (III) onto polythiophene/Fe2O3 nanocomposites was found to be strongly dependent on the solution pH. The optimum conditions of sorption were found to be: contact time of 40 min, 0.1 g of adsorbent dosage and pH 6 . Among of the several conventional isotherm and kinetic models, langmuir and second-order models showed reasonable fit to the adsorption equilibrium data, respectively.