Glutathione‐Titanate Nanosheets for the Adsorption of Lysozyme from Aqueous Solution: Kinetic, Isotherms, and Thermodynamic Studies

Abstract

In this study, GSH‐γ‐MAPS‐TiNS nanosheets were prepared and characterized using scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), X‐ray photoelectron spectrometric (XPS), contact angle, and specific surface area (BET). The characterization results confirmed GSH‐γ‐MAPS‐TiNS have been successfully synthesized, and the nanosheets structure and satisfactory hydrophilicity have been obtained. The synthesized composites were applied for the adsorption of lysozyme from aqueous solution, and the effects of operation parameters on adsorption efficiency were optimized. The results of adsorption kinetics demonstrated that the process followed pseudo‐second‐order kinetic model. Moreover, the adsorption isotherm was well described by Freundlich model, which implied that multilayer adsorption occurred on prepared nanosheets for lysozyme adsorption. The negative values of Gibbs free energy change (ΔG°<0) demonstrated that lysozyme adsorption was a spontaneous process. The positive values of entropy change (ΔS°>0) implied that lysozyme adsorption was an increasing random process. Enthalpy change values were positive (ΔH°>0), indicated that lysozyme adsorption was endothermic. Furthermore, GSH‐γ‐MAPS‐TiNS was treated sequentially with MeOH for regeneration, achieving a high desorption percentage of 91.76 %. The intra‐batch and inter‐batch RSD values were determined to be 2.2 and 8.2 %, respectively. These results indicated that GSH‐γ‐MAPS‐TiNS have the potential ability for the adsorption of lysozyme from aqueous solution.