Abstract

Sumathi Ganesan and Gurumallesh Prabu Halliah*

DOI : http://dx.doi.org/10.13005/ojc/350623

Graphene oxide/Chitosan (GOCH) composite was synthesized by hydrothermal method and structurally characterized by FT-IR, RAMAN, XRD and BET analyses which provide support for graphene oxide and chitosan incorporation. The synthesized composite was employed for the removal of direct red 7 (DR7) by batch adsorption process. Langmuir, Freundlich, Temkin, Dubinin-Radushkevic, Harkin-Jura, Scatchard plot analysis and Hasley isotherms were used to elucidate adsorption mechanism. The value of R2 revealed that isotherm was well explained by Langmuir model. The extent of monolayer adsorption capacity of GOCH was calculated as 34.2 mg/g. The pseudo first order kinetic studies were in agreement with experimental data. Thermodynamic parameters such as activation energy (Ea = 8.405 KJ/mol), enthalpy (ΔH = 89.417 KJ/mol), free energy change (ΔG) and entropy (ΔS = 0.2971 KJ/mol) were calculated. It propounded that the adsorption of DR7 on GOCH was favorable, spontaneous and an endothermic process.

Adsorption; Chitosan; Direct Red 7; Graphene Oxide

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