Fe2O3/polypyrrole/peanut husk composite for the adsorptive removal of Basic Blue 41 from the aqueous medium: Kinetics, equilibrium modeling and thermodynamic studies

Abstract

In this study, Basic Blue 41 (BB41) was adsorbed from an aqueous medium using a peanut husk (PH) functional composite with polypyrrole/Fe3O4. For the adsorption of BB41 dye, the effects of process variables including pH, sorbent dose, dye concentration, agitation time, and temperature were investigated. The magnetic composite showed the highest efficiency for the adsorbents at pH 7-10, 0.05 g adsorbent dose, 90 min contact time and 200 mg/L initial dye concentration at 27 °C. The qe was found up to 48 mg/g with percentage removal of up to 96% for BB41 dye for the composite. On the experimental data of BB41 dye, the Langmuir, Freundlich, Temkin, Harkin-Jura, and Dubinin-Radushkevich isotherms were applied. The BB41 adsorption data were also subjected to pseudo-first order, pseudo-second order, and intraparticle diffusion kinetic models. Thermodynamic factors, such as the change in enthalpy (ΔH°), entropy (ΔS°), and Gibbs free energy (ΔG°), were also calculated. The results show that the BB41 adsorption process is exothermic and spontaneous. Techniques such as FT-IR and scanning electron microscopy (SEM) were used to characterize the composite materials. This study demonstrated the promising adsorption potential of magnetic/polypyrrole/peanut husk composites. This class of adsorbent could be used to remediate wastewater that contains dyes.