Synthesis of Magnetic Graphene Oxide ‎Nanocomposite for Adsorption Removal of ‎Reactive Red 195: Modelling and ‎Optimizing via Central Composite Design

   In this work, magnetic graphene oxide (MGO) was prepared by in situ synthesis of magnetite nanoparticles in the presence of graphene oxide (GO). The prepared nanocomposite was characterized by applying scanning electron microscopy (SEM), X-ray diffraction (XRD, Fourier transform infrared spectroscopy (FTIR) and vibrating sample magnetometer (VSM). MGO was applied as an efficient nano-sorbent for adsorptive removal of reactive red 195 (RR195). The adsorptive removal process of RR195 was modeled and optimized using the response surface methodology (RSM) based on central composite design (CCD). Important parameters influencing the adsorption of RR195 including pH, contact time, initial concentration of RR195 and adsorbent amount were selected as input variables for RSM. The highest adsorption capacity of MGO sorbent (77.2 mg g-1) was obtained at an initial dye concentration of 325 mg L-1, contact time of 65 min, adsorbent amount of 89.4 mg, and pH of 3.  Moreover, the adsorption isotherms and kinetics studies were performed, indicating that the adsorption process best fitted in pseudo-second-order model and Langmuir isotherm model, in which the maximum adsorption capacity, qm, was calculated to be 80 mg g-1.