Efficacy assessment of natural zeolite containing wastewater on the adsorption behaviour of Direct Yellow 50 from; equilibrium, kinetics and thermodynamic studies

This study aimed to evaluate an efficient method in order to remove Direct Yellow 50 (DY50) dye from aqueous solutions using natural zeolite in a batch system. The results indicated that the removal of DY50 was highly subjective to the pH of the aqueous solution, initial concentration of DY50, adsorbent dosage, temperature, and contact time. The research data was then tailored isothermally to the Freundlich and Langmuir isotherms, and the kinematic results were interrelated to the pseudo-first and second-order models. The removal rate of DY50 was calculated to be 58.63% for a zeolite sample of 0.05 g and 40 mg L-1 as a preliminary dye concentration with 4 hrs of contact time. The description of the adsorptive behaviour of the natural zeolite was presented through a kinetic model of the pseudo-second-order. The change in enthalpy (Delta H), free energy (Delta G), and entropy (Delta S) were also investigated as thermodynamic parameters. The results of this study supported the theory that the initial concentration of DY50, pH of solution, adsorbent mass, contact time, and temperature, greatly affected the adsorption of DY50 on zeolite. (C) 2021 The Author(s). Published by Elsevier B.V. on behalf of King Saud University.