New hybrid nanocomposite of copper terephthalate MOF-graphene oxide: synthesis, characterization and application as adsorbents for toxic metal ion removal from Sungun acid mine drainage.

The application of a hybrid Cu(tpa).GO (Cu(tpa) copper terephthalate metal organic framework, GO graphene oxide) composite as a new adsorbent for the removal of toxic metal ions was reported. New hybrid nanocomposite with excellent dispersibility and stability was successfully fabricated by the simple and effective ultrasonication method. The synthesized composite was characterized by scanning electron microscopy (SEM), UV-Vis and Fourier-transform infrared (FT-IR) techniques. The characterization results concluded that the binding mechanism of the Cu(tpa) and GO was related to both π-π packing and hydrogen bonding. For scrutinizing the sorption activity, the prepared adsorbents were assessed for the removal of Mn, Cu, Zn, Cd, Pb and Fe metal ions from aqueous synthetic solution and also acid mine drainage (AMD) wastewater. The sorption experiments demonstrated that the removal efficiency was significantly improved by modified hybrid Cu(tpa).GO composite, owing to the significant number of active binding sites and unique structure formed based on π-conjugated networks. Also, it was shown that the adsorption reaction was mainly attributed to the chemical interactions between metal ions and the surface functional groups. Moreover, kinetic and adsorption studies clarified that the adsorption process onto the Cu(tpa).GO follows a pseudo-second-order kinetics and fits the Langmuir and Freundlich adsorption models. Holistically, the results of this research represent that applying Cu(tpa).GO can be remarked as an effective adsorbent with high possibility at conventional water treatment.