Hydroxide-rich polypropylene hybrid microparticles for the removal of reactive yellow 145 from aqueous solutions: equilibrium, kinetic and thermodynamic studies

Cleaning wastewater from harmful dyes is mandatory to keep the safety of humans and other lives forms. In this study, hybrid polypropylene/metal hydroxide microparticles were presented for the removal of reactive yellow 145 (RY145) from aqueous solutions. The chemical structure and morphological features of the adsorbent were studied by Fourier transform infrared (FT-IR), energy dispersive X-ray spectroscopy (EDS) and scanning electron microscopy (SEM). To achieve high adsorption efficiency, the adsorption process was optimized using different adsorbent doses, pH of the medium, time intervals and temperature. Kinetic and isotherm models were utilized to analyze the adsorption data. The pseudo-second order and Langmuir models showed the best fit for the adsorption process. A maximum adsorption capacity of 39.62 mg g^-1 was attained at 25 °C and neutral pH. The thermodynamic parameters of the adsorption process were estimated. The adsorption process increased by increasing temperature revealing that the adsorption is endothermic (∆ H = 25.52 kJ mol^-1 K^-1) but random (∆S = 90.61 J mol^-1 K^-1) and feasible (∆G = - 1.48 kJ mol^-1). Hence, it can be concluded that the adsorption process was endothermic but random and feasible.