Adsorption Kinetics, Mechanism, Isotherm, and Thermodynamic Analysis of Paclitaxel from Extracts of Taxus chinensis Cell Cultures onto Sylopute

The adsorption characteristics of paclitaxel from extracts of Taxus chinensis cell cultures by the commercial adsorbent Sylopute were investigated using different parameters such as initial paclitaxel concentration, adsorption temperature, and contact time. The equilibrium adsorption data were best represented with the highest accuracy (r(2) > 0.984, RMSD<0.0009) by the Langmuir isotherm. It was found that the adsorption capacity increased with increasing temperatures and the adsorption of paclitaxel onto Sylopute was favorable. The kinetic data fit the pseudo-second-order model well, and intraparticle diffusion played a dominant role in paclitaxel adsorption according to the intraparticle diffusion model. Thermodynamic parameters such as Delta H-0, Delta S-0, and Delta G(0) were also calculated. The results indicate that the process of paclitaxel adsorption onto Sylopute is endothermic and nonspontaneous. The isosteric heat of adsorption, Delta H-x (20-25 kJ/mol), was nearly a constant, even with variations in surface loading (q(e): 3-9 mg/g), indicating a homogeneous surface.