Abstract

Polypyrrole (PPy)-based adsorbents have successfully been prepared via oxidative polymerization in aqueous media as a new adsorbent for the removal of arsenic ions in a batch equilibrium system. The prepared adsorbent was characterized by the Brunauer–Emmet–Teller (BET) surface analyzer, field emission scanning electron microscopy (FESEM), and attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR). The BET surface area and average particle size of the prepared PPy powder was 10.27 m2/g and ∼180–295 nm, respectively. Different adsorption parameters, such as adsorbent dosage, contact time, pH of the initial solution, temperature, initial ions and co-ions concentrations were investigated. The results showed that PPy powder acted as an effective sorbent for the removal of arsenic ions at the optimum conditions of pH 6.5 and a contact time of 6 h. The experimental data of PPy isotherms for arsenic ions followed the Freundlich isotherm model and kinetics data were well fitted to the pseudo-first-order model. Thermodynamically, the adsorption process was endothermic and spontaneous in nature. The FTIR and FESEM-EDX results also confirmed the presence of arsenic in adsorbents after adsorption. The presence of amine groups in PPy is believed to play the key role of adsorption of arsenic ions.

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