Kinetic and Thermodynamic Study on the Removal of Congo Red from the Aqueous Solution Using Graphene Oxide/Magnesium Oxide Nanocomposite

Amir Fahdil , Dawood AL-Niaimi , Firas Hassan Muhi

Abstract

In this investigation, graphene oxide/magnesium oxide (GO/ MgO NCs) Nanocomposite with GO/MgO weight ratio of 1:1 was used to removal Congo red dye from aqueous solution in batch method. The prepared NCs were characterized using scanning electron microscopy, X-ray diffraction, FTIR, Atomic force microscope, and Brunauer, Emmett and Teller (BET). The results showed that MgO particles were successfully graced on GO. The effects of different empiric variables on the Congo red dye removal including GO/MgO NCs weight, initial concentration, contact time, and pH were investigated. The experimental analysis of adsorption isotherms (Langmuir, Freundlich, Dubinin, Temkin) indicated that adsorption data were best fit with the Freundlich isotherm model. The kinetic adsorption data were best expressed by the pseudo-second-order kinetic model. Thermodynamic function data such as (ΔHº, ΔGº, ΔSº) of adsorption were calculated, which showed the adsorption exothermic process and the value of ΔGº was negative and indicated that the process happened spontaneously while the value of ΔSº was positive, meaning that the movements of dye molecules is unlimited



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