Activated Bamboo Charcoal by ZnCl2 as Remazol Yellow FG Adsorbent: Isotherm, Kinetic, and Thermodynamic Studies

This study aimed to determine the isotherm, kinetics, and thermodynamics of Remazol Yellow FG adsorption by ZnCl2-activated bamboo charcoal. The research began with preparing activated charcoal from bamboo stems using ZnCl2, and then the quality was characterized according to the SNI. The adsorption isotherms were tested against Langmuir and Freundlich models, and the kinetics were examined for pseudo-first and pseudo-second orders. The thermodynamic parameters, which were enthalpy (∆Ho), entropy(∆So), and free energy (∆Go), were also determined. The results showed that the adsorption followed the Langmuir isotherm with the adsorption capacity of 45.4545 mg/g, and the kinetic model corresponded to the pseudo-second order. The values of ∆Ho, ∆So, and ∆Go using different concentrations of Remazol Yellow RG of 100 and 300 mg/L at the optimum conditions of contact time of 240 minutes, the temperature of 303K, and pH 2 were -99.768 and - 83.971 KJ/mol; - 0.302 and - 0.239 KJ/mol; -8.383 and -11.433 KJ/mol, respectively. The adsorption was exothermic (∆Ho < 0), followed by a decrease in entropy (∆So < 0), and the process was spontaneous (∆Go < 0) and controlled by chemical adsorption.