EQUILIBRIUM AND THERMODYNAMICS STUDIES FOR DECOLORIZATION OF REACTIVE BLACK 5 BY ADSORPTION ONTO ACID MODIFIED BANANA LEAF ASH

Abstract

Background and purpose: At present study, acid modified banana leaf ash was used as an adsorbent for the successful removal of Reactive Bl ack 5 (RB5) dye from aqueous environments. Materials and Methods: The effect of various operating parameters such as pH of solution, dye concentration, contact time, adsorbent dosage, and the temperature was investigated . Results: Maximum adsorption capacity of the banana leaf ash was 191.32 mg/g at pH 2, the initial concentration of 200 mg/l and 323° K when 9 5.66% of the dye was removed. The process followed pseudo-second-order kinetics. Furthermore, equilibrium data were better represented by Freundlich isotherm among Langmuir, Freundlich, Temkin, and Dubinin-Radushkevich equilibrium isotherm models. The negative values of free energy change confirmed the feasibility of the process and the spontaneous nature of adsorp tion. Furthermore, from the magnitude of ∆H, the process was found to be endothermic physisorpti on. Conclusion: According to the results of this study, it was fou nd that the acid modified banana leaf ash is not only a low-cost adsorbent, but also has high performance in the removal of RB5 from aqueous environments. [Bazrafshan E, Rahdar S, Mostafapour FK, Balarak D, *Zazouli MA. Equilibrium and Thermodynamics Studies for Decolorization of Reactive Black 5 by Adsorptio n onto Acid Modified Banana Leaf Ash . Iran J Health Sci 2015; 3(3): 15-28] http://jhs.mazums.ac.ir