Removal of basic dyes (malachite green) from aqueous medium by adsorption onto amino functionalized graphenes in batch mode

In this paper, graphene oxides and amino functionalized graphenes (NH2-G) were prepared and employed as adsorbent for the removal of a basic dye, malachite green (MG). The effect of several parameters (pH, dye concentration, adsorption time, and temperature) of the adsorption process was investigated for NH2-G. Four different adsorption isotherms were used to analyze the equilibrium of the adsorption system. The adsorption mechanism was investigated by adsorption thermodynamics and adsorption kinetics. The results indicated that NH2-G showed a high efficiency for the removal of the basic dye MG with the maximum adsorption capacity of 91.48 mg g(-1). According to the obtained thermodynamic data, the adsorption of MG onto NH2-G was an endothermic process with a large adsorption enthalpy. The kinetic study showed that the whole adsorption process fit the pseudo-second-order kinetics model well.