Thermodynamics and Kinetic Study for Removal of Orange-G Dye from Aqueous Solution by Nano Composite

Abstract

In this study, where graphene oxide was prepared by Hummer method, while copper oxide was prepared in the green way using (capparies spinosa) plant extract as a reducing agent, these oxides were diagnosed as well as the binary nanocomposite by several techniques including Fourier Transform Infrared Spectroscopy (FTIR), X-rays diffraction , and field Emission scanning electron microscopy (FESEM), after that the superimposed (GO/CuO) was used to adsorbent the orange G dye ( Orange - G) from its aqueous solutions,  A number of factors affecting adsorption were studied (equilibrium time, surface weight, pH, concentration effect, temperature). The results showed that the ideal time for adsorption of the orange dye (orange-G) on the surface of the nanocomposite (GO/CuO) was (30min), the best ideal weight for dye removal was (0.05gm), the best concentration was (20ppm), and the best acid function was (pH=2). After that, the adsorption kinetics were also studied by applying the pseudo first and second order of adsorption. The results showed that the adsorption process follows the false second-order kinetics.  The thermodynamic functions of the removal process were also studied, and it was found that the value of (DH) is negative for the surface of the composite (GO/CuO) with dye. Meaning the adsorption process is exothermic, and that the DG⁰ has negative value, meaning that the adsorption processes occur spontaneously. positive DS⁰ values indicate that the molecules are becoming less bound