An investigation on kinetic and thermodynamic parameters of methylene blue adsorption onto graphene-based nanocomposite

In this work, adsorption of methylene blue (MB) onto graphene-based nanocomposite adsorbent has been evaluated on the adsorbent kinetic and thermal parameters sides. Specially, graphene (Gr) was prepared from waste dry battery electrode using a simple electrochemical method and prepared graphene has been used for fabrication of a Fe3O4/chitosan/graphene (FCG) nanocomposite by a simple co-precipitation method. Experimental results indicated the adsorption of MB onto FCG follows the pseudo-second order kinetic models as described: t/q(t) = 0.02162 + 0.02076.t with R-2 = 0.99852. Thermodynamic parameters of the adsorption of MB onto FCG were evaluated in temperature range from 283 K to 323 K and extracted data have provided values of Delta G(O), Delta H degrees of -9.950 divided by 6.434 kJ mol(-1) and 27.348 kJ mol(-1), respectively. The negative values of Delta G(O), indicate the adsorption of MB onto FCG phenomenon occurred spontaneously. The positive value of Delta H degrees suggests the endothermic in nature and small value of Delta H degrees also implies a physical adsorption. These obtained results are useful to control the adsorption of MB onto graphene-based nanocomposite adsorbents in term organic dyes removal from solution.