Surface modified polypyrrole for the efficient removal of phenolic compounds from aqueous medium

Abstract

In this study, we have reported the effect of acid doping on the adsorption of phenolic compounds on polypyrrole (PPy) particles. Both the in-situ doping and post-doping methods were adopted for the preparation of acid doped PPy particles. It is observed that acid doped PPy showed a higher adsorption capacity than the pristine PPy. It has also been observed that both in-situ doped and post-doped PPy have similar effect on adsorption. Electrostatic interaction, hydrogen bonding and ππ interactions are assumed to be responsible for the adsorption. The adsorbents were characterized by FTIR, XRD, SEM and TGA. Batch adsorption experiments were performed under different experimental conditions. Thermodynamic and kinetic parameters were determined from the adsorption experiments. The Langmuir, Freundlich and Temkin isotherm models have been utilized to fit the experimental data. The experimental data fits best in Langmuir model. The Langmuir adsorption capacity of pristine PPy and post-doped PPy were found to be 21.3 and 31.6 mg/g for phenol and 29.3 and 43.6 mg/g for resorcinol respectively. The thermodynamic studies show negative ΔG and positive ΔH values for both phenol and resorcinol. The adsorption data fit best with pseudo first order kinetic model.