A GO-CS@MOF [Zn(BDC)(DMF)] material for the adsorption of chromium(VI) ions from aqueous solution

In the present study, a novel nanocomposite adsorbent material was synthesized using chitosan (CS), graphene oxide (GO) and metal organic framework (MOF [Zn(BDC)(DMF)]) for the adsorption of Chromium (VI) heavy metal from aqueous solution. The characterization of the prepared GO-CS@MOF [Zn(BDC)(DMF)] was accomplished by powder X-ray diffraction (PXRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET), followed by Cr(VI) adsorption-desorption studies. Experimental parameters such as effect of pH, temperature, contact time, adsorbent dosage and shaking speed were optimized. The GO-CS@MOF [Zn(BDC)(DMF)] showed an adsorption capacity of 144.92 mg/g for Cr(VI) at pH 3.0. Thermodynamic properties (ΔGo, ΔHo, ΔSo) have been calculated and the process is found to be endothermic, favourable and spontaneous. The adsorption study of Cr(VI) by GO-CS@MOF [Zn(BDC)(DMF)] comprises both kinetic and isotherm studies. The equilibrium adsorption followed Langmuir model and adsorption reaction was found to be pseudo-second order confirming chemisorption. The developed GO-CS@MOF [Zn(BDC)(DMF)] nanocomposite material will serve as a new type of platform for removing Cr(VI) from wastewater.