Preparation and characterization of a composite based on polyaniline, polypyrrole and cigarette filters: adsorption studies and kinetics of phenylbutazone in aqueous media

Understanding the adsorption mechanisms of drugs on the surfaces of solid materials is important for determining the fate of these compounds in aqueous samples during water or wastewater treatment. A composite based on polyaniline (PAni), polypyrrole (PPy) and cigarette filters (CFs), PAni-PPy-CFs, was prepared, characterized by FTIR, TGA and SEM and applied in the investigation of the adsorption of a non-steroidal anti-inflammatory, phenylbutazone (PBZ), from aqueous solution. A group of experiments were conducted, and four kinetic models and five isotherm models were used to describe the adsorption process. The experimental kinetic data fitted very well with the second-order kinetic model, indicating that PBZ adsorption involves chemical adsorption at different binding sites, which could control the reaction rate. The equilibrium adsorption data were best fitted with the dual-site Langmuir-Freundlich isotherm, with a maximum adsorption capacity of 100.22 mg g(-1); this indicates the existence of two kinds of adsorption sites on the polymer composite surface. Finally, this composite may act as a excellent adsorbent for environmental and analytical processes, such as a stationary phase in separation processes.