Mechanisms and Equilibrium Studies of Sorption of Metronidazole Using Graphene Oxide

In this work, the removals of Metronidazole (MTZ) antibiotics onto Graphene Oxide (GO) adsorbent from aqueous solutions were studied. Batch adsorption studies were carried out at different contact time, MTZ concentrations, and temperatures. Adsorption isotherms have been modeled by Freundlich, Langmuir, Toth and Redlich-Peterson (R-P) equations. The adsorption of MTZ antibiotics was better represented by the Langmuir equation. The effect of temperature was also studied at the range between 298 and 328 K. Thermo- dynamic parameters were calculated. The positive value of enthalpy change (ΔH°) indicated the endothermic nature of the adsorption process, and the negative values of free energy change (ΔG°) were indicative of spontaneity of the adsorption process. In this work adsorption behavior of MTZ on GO sorbent was also evaluated by the data obtained from batch experiments. The positive values of ΔS° suggest the increased randomness at the sorbent–solution interface during the sorption of MTZ from the aqueous solution to the GO sorbent.