Metal oxide based adsorbents have been limited for adsorption of Cr (VI) from the aqueous solution because of their low adsorption capacities and slow adsorption kinetics. In this present study, we synthesized & decorated ZnO nanoparticles on the surface of graphene oxide via a solvothermal process. The deposition of ZnO NPs on graphene oxide, forming the nanohybrid (ZnO-GO), improves Cr(VI) mobility in the nanocomposite or nanohybrid, thereby improving the Cr(VI) adsorption kinetics and removal capacity. Surface deposition of ZnO on graphene oxide was characterized through FTIR, UV, EDX, FEMSEM, BET and AFM techniques. These characterizations confirm the formation of ZnO-GO nanocomposite with a specific area of 32.95 mg/g and pore volume of 0.058 mg/g. Batch adsorption experiments were carried to evaluate the influence of operational parameters, equilibrium isotherm, adsorption kinetics, and thermodynamics. The removal efficiency of Cr (VI) increases with increasing time and adsorbent dosage. However, the removal efficiency increases from high-alkaline to neutral pH and then decreases under acidic conditions. Mathematical modelling confirms that the data is well fitted to Langmuir and pseudo order kinetics model showing homogeneous adsorption process. To the best of our knowledge, th is the first study of Cr (VI) removal from aqueous solution using this hybrid nanocomposite. The hybrid composite exhibits strong interaction with Cr(VI) as revealed from FTIR experiments. Thus, the synthesized nanocomposite has a potential for Cr (VI) remediation.

Facile synthesis and characterization of ZnO nanoparticles decorated on graphene oxide for efficient removal of Cr(VI) frp, aqueous solutions

ACS Fall 2021

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