Removal of Bromocresol Green from Aqueous Solution via Adsorption on <i>Ziziphus nummularia</i> as a New, Natural, and Low-Cost Adsorbent: Kinetic and Thermodynamic Study of Removal Process

Abstract

In this study Ziziphus nummularia (ZPN) as a good, available and inexpensive adsorbent has been introduced and used for the removal of Bromocresol Green (BCG) from several water solutions successfully. The effect of various parameters such as pH, dye concentration, amount of adsorbent, size of adsorbent particles, and contact time on removal processing was investigated. To investigate the mechanism of adsorption, several kinetic models were tested including Lagergren, pseudosecond-order, particle diffusion, film diffusion, and Elovich models. Adsorption isothermal data could be interpreted by the Langmuir, Freundlich, Tempkin, and Dubinin–Rudushkevich (DR) isotherm models. Thermodynamic parameters like free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of the system were calculated.