Adsorption and Controlled Release of Pefloxacin Mesylate from Aqueous Solution by Coconut Shell Activated Carbon

The effect of activated carbon made from coconut shell on adsorption and controlled release of pefloxacin mesylate (PFLX) in aqueous solution was studied. The adsorption isotherms had been measured at different temperatures. The adsorptive free energy, enthalpy and entropy in adsorption processes had been calculated by the Langmuir and Freundlich equation.The result showed that adsorption of PFLX was in accord with Freundlich equation.The heat of absorption ΔH was 6405 9 kJ/ mol, which demonstrated that the absorption was an endothermic process, when ΔH<20 kJ/ mol, it indicated that the adsorption process was mostly physical adsorption. Meanwhile, Gibbs free energy ΔG< 0，which indicated that the adsorption was a spontaneous process. The results indicated that the value of ΔS was positive and it′s the main driving force of adsorption. Modified activated carbon of nitrate oxidization possessed had more controlled release capacity compared with coconut shell activated carbons. The different activated carbon controlled release process marched with Higuchi equation.