Rational synthesis and characterization of highly water stable MOF@GO composite for efficient removal of mercury (Hg(2+)) from water()

The present study is aimed at adsorptive removal of Mercury (Hg(2+)) using highly functionalized nanomaterials based on Graphene Oxide Zeolitic Imidazolate Framework composite (ZIF-67@GO). Solvothermal methodology was used to synthesize ZIF-67@GO composite. Synthesized compounds were confirmed by FTIR, SEM, PXRD and EDX analysis. The as-prepared ZIF-67@GO was tested as efficient adsorbent for effective removal of Mercury (Hg(2+)) from aquatic environment. The atomic adsorption spectrophotometer was used to monitor the process of adsorption of Hg(+2) on ZIF-67@GO. From the adsorption data, the maximum removal efficiency achieved was 91.1% using 10 mg amount of composite for 50 mL using 20 ppm Mercury (Hg(2+)) solution. Different parameters like pH, contact time, concentration, adsorption kinetics and isotherm were also examined to explore adsorption process. Adsorption data fitted well for Freundlich Model having R(2) value of 0.9925 than Langmuir Isotherm with R(2) value of 0.9238. Kinetics were rapid and excellently described via 2nd order model with R(2) = 0.99946 than 1st order model with R(2) value of 0.8836. Freundlich and pseudo 2nd order models validated that multilayer chemisorption occurs during adsorption process due to the presence of highly functionalized sites on ZIF-67@GO composite. The synthesized composite material has shown excellent reusability. Thus, water stable ZIF-67@GO composites can efficiently be used for Mercury (Hg(2+)) confiscation from water.