Facile synthesis of chitosan/magnesium oxide/polyethylenimine novel composite for the efficient removal of Congo red dye from aqueous media

In this work, chitosan/ magnesium oxide/polyethylenimine was synthesised as a novel composite. The synthesised composite formed via crosslinking polymerisation of chitosan with polyethylenimine in the presence of epichlorohydrin and magnesium oxide nanoparticles. The synthesised composite was identified using several instruments such as FT-IR, XRD, SEM, and BET. The XRD of the chitosan/magnesium oxide/polyethylenimine composite confirmed the appearance of two broad XRD peaks at 2 circle minus = 8.90 degrees and 20.30 degrees. Also, the XRD confirmed the obvious destruction of the crystalline structure of magnesium oxide. The SEM image confirmed that the composite is composed of a flaky surface with some irregular and rod shapes. The BET surface area, average pore radius, and total pore volume of the chitosan/magnesium oxide/polyethylenimine composite are 112.63 m(2)/g, 16.28 nm, and 0.26 cc/g, respectively. The synthesised composite was utilised for the efficient removal of Congo red dye from aqueous media where its adsorption capacity is 1258.68 mg/g. The adsorption process of Congo red dye follows the pseudo-second-order model and Langmuir isotherm. Also, the adsorption process of Congo red dye is favourable, spontaneous, endothermic, and chemical. The analytical factors that achieved the highest % removal of Congo red dye are observed at pH = 2, contact time = 140 min, and temperature = 328 kelvin.