Abstract:
In this study, adsorption of hexavalent chromium has been examined on ZF 8 and its various
composites. ZIF8 is modified by using amine groups, GO and Mg(OH)2/GO. Trend of pure
ZIF8, Mg(OH)2/GO, ZIF8/NH2, ZIF8/Mg(OH)2/GO, ZIF8/NH2/GO and
ZIF8/NH2/Mg(OH)2/GO for Cr(VI) removal was studied. Several characterization techniques
were conducted for structural and surface characterization i.e. Fourier Transform Infrared
Spectroscopy (FTIR), X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), and
Brunauer–Emmett–Teller (BET) surface area analysis. The influence of different adsorption
parameters (contact time, pH, initial concentration of Cr(VI) and absorbent dosage) were
studied in batch experiments. Different kinetic and isotherm models were applied on
equilibrium data.The adsorption process of ZIF8 and its composites was better described by
pseudo-second-order kineticmodel and Langmuir isotherm, with maximum removal efficiency
of 98% for Cr(VI) by ZIF8/NH2/Mg(OH)2/GO, whose adsorption capacity has greatly
improved when compared witha single ZIF 8 or Mg(OH)2/GO.
