Synthesis of polythiophene/zeolite/iron nanocomposite for adsorptive remediation of azo dye: optimized by Taguchi method

Herein, we report adsorptive removal of methylene blue as model pollutant dye by polythiophene/zeolite/iron magnetic nanocomposite, which was synthesized by chemical polymerization method. The operating process parameters, including adsorbent dose, pH, temperature, contact time, and initial concentration of dye, were optimized by Taguchi experimental design (L16 orthogonal array). The results showed that the nanocomposites containing 50 wt% of zeolite and 25 wt% of iron magnetic nanoparticles (i.e., relative to the molecular mass of thiophene monomer) had a robust structure with high removal efficiency. The analysis of experimental isotherm data revealed that Toth model better described the adsorption process, and the maximum adsorption capacity of 319.4 mg/g was obtained at 80 °C. Additionally, it was found that the adsorption process was endothermic. The kinetic study also showed that the adsorption kinetic follows a pseudo-second order. The as-synthesized nanocomposite showed an excellent reusability up to 6 cycles of adsorption, owing to its multifunctional structure and magnetic properties. This study indicates the importance of designing nanoporous nanocomposites based on various nanomaterials to obtain recyclable adsorbents with high adsorption capacity for the removal of pollutant dyes from wastewater streams.