Improving the Co-removal Efficiency of Dyes from Water by a Novel Four-Component Chitosan Flexible Film Containing Graphene Oxide

In the present study, a quaternary composite consisting of alpha-ketoglutaric acid, chitosan, polyaniline, and graphene oxide (alpha-CTS-PANI-GO) was synthesized and characterized by Scanning Electron Microscope, Fourier Transform Infrared Spectroscopy, and Raman spectroscopy. The adsorption of dye on the film was proved by the X-ray diffraction analysis method. According to the increase in the intensity of the peak before and after adsorption, it showed the presence of Methylene Blue (MB) and Acid Orange 7 (AO7). Also, the appearance of peaks related to sulfur in Energy dispersive X-ray (EDX) and EDX elemental mapping, and X-ray photoelectron spectroscopy data after the adsorption process proved the presence of dyes compounds and their adsorption by the synthetic film. The simultaneous removal properties of alpha-CTS-PANI-GO were evaluated in the removal of cationic and anionic dyes, MB and AO7. Using the Central Composite Decomposition, the effect of different variables such as pH, temperature, adsorbent dose, and time on AO7 and MB removal was studied. The regeneration of alpha-CTS-PANI-GO film was studied and the zero point charge of the synthesized film was also determined. Various isotherm models, such as Langmuir and Freundlich, were investigated, and the processing of experimental equilibrium data confirmed the suitability and application of the Langmuir model. Analysis of experimental adsorption data using various kinetic models, such as pseudo-first and second-order models, shows the applicability of the first-order equation. The results showed that in the optimal conditions, the removal percentage was about 95% for AO7 and 80% for MB, which indicates the successful performance of the synthetic film compared to the method.