Adsorption characteristics of gallic acid on fresh calcium phosphate in sucrose solution

摘要

The adsorption characteristics of gallic acid on fresh calcium phosphate in sucrose solution were discussed. Three kinetic models, including pseudo-first-order model, pseudo-second-order model and intraparticle diffusion model, were selected to follow the adsorption processes. The results which adsorption reaction occurred in 10% sucrose solution showed that the pseudo-second-order equation provided the best correlation to the experimental data (R~2=0.9908～0.9964). Under the initial gallic acid concentration were 25, 50, 75 mg·L~(-1) in the 10.0% sucrose solution, the adsorption rate of gallic acid on fresh calcium phosphate were 0.0614, 0.0368, 0.0149 g·mg~(-1)·min~(-1), respectively. Adsorption isotherms curves of gallic acid from different concentrations of sucrose solution on fresh calcium phosphate all conforms to the Langmuir model (R~2=0.9919-0.9965). The sucrose solution concentration had effect on the saturated adsorption capacity of gallic acid. The maximum adsorption capacity of gallic acid were 8.4317, 8.0906, 7.7160, 7.3964, 7.0872, 7.0771 mg·g~(-1) as sucrose concentrations were 0.0%, 0.1%, 0.5%, 1.0%, 5.0% and 10.0%, respectively.