Effect of surface area enhancement on the adsorption of bovine serum albumin onto titanium dioxide

The equilibrium and the kinetics of BSA adsorption onto specific surface area changed TiO2 by heat treatment were studied. The TiO2 was treated at 100 and 200 degrees C for 24 h. The specific surface areas of TiO2 characterized by BET method were measured as 48.9 m(2)/g and 53.0 m(2)/g for 100 and 200 degrees C, respectively. The adsorption rate and the equilibrium experiments were carried out at pH 4 for 40 degrees C. The rate kinetics for the adsorption of BSA was best fitted with the pseudo-first-order kinetic model. The equilibrium process was described by the Langmuir and Freundlich isotherm models. The adsorption capacities (Q(0)) calculated from the Langmuir isotherm model were 40.6 and 44.4 mg/g for heat-treated TiO2 at 100 and 200 degrees C, respectively. The adsorption of BSA increased with increasing surface area of TiO2. The zeta potential values of the 100- and 200 degrees C-treated TiO2 were found as -2.57 mV and 0.39 mV, respectively, showing that the interaction between TiO2 with BSA increased with increasing temperature of heat treatment for TiO2. (C) 2009 Elsevier B.V. All rights reserved.