Study On The Adsorption Activities And Applications Of Resins Of Chitosan-Ce(Ⅳ) And Chitosan Microspheres

Resins of chitosan(RCM) and chitosan-Ce(â…£) microspheres(RCCM) are prepared by using reverse phase suspension crosslinked polymerization. Both resins are used in debittering of citrus juice and deturbiding of tea drinks. Study the thermodynamics and kinetics of adsorption of citric acid and tea polyphenols on RCM and RCCM.Both batch experiment and column technique are used to investigate the debittering effect of RCCM on citrus juice. In addition, the effects of different methods on the main nutrient compositions, colour and aroma components of orange juice are also studied. The results of the experiment show that the quantity of naringin and limonin are reduced by 54.86% and 43.20% in juice treated by RCCM, respectively. The content of titratable acid is also reduced. So RCCM can also be used in deacidification of citrus juice. And the juice contains most nutritive compositions, beside Vc and total phenols. It is indicated from column technique results that the content of amino acid in juice is increased 5.52%. Moreover, most aroma constituents don't change but esters. At the same condition, the citric juice is treated by RCM. The results show that the content of amino acid in juice is reduced. So the debittering effect of RCCM is better than that of RCM.Both RCM and RCCM are applied to prevent the turbidity of green tea drink. The results show that both RCM and RCCM can reduce the quantity of tea polyphenols and improve the stability of tea drinks. While the quantity of tea polyphenols is reduced by 40% to 50%, other nutrient compositions are reserved well. The clarity is significantly improved, most aroma constituents don't change. The content of amino acid in tea drinks treated by RCCM is increased. So RCCM can improve the quality of tea drinks. Compared with RCCM,RCM can also reduce the quantity of tea polyphenols, but the contents of protein and amino acid are reduced. These methods can also be used for oolong tea and black tea drinks. Study the adsorption activities of citric acid and tea polyphenols. The main research contents: the thermodynamics and kinetics. The adsorption isotherms can be fitted by Langmuir equation. The thermodynamics parameters of adsorption are determined,includingâ–³H,â–³S,â–³G and Polanyi adsorption potential. The order of the reaction and rate constant are determined. And apparent activation energy is calculated. These studies provide theoretical foundation for application on citric juice and tea drinks.The results show that the adsorption activities of citric acid on RCM and RCCM are similar with tea polyphenols. The adsorption process basically follows the Langmuir equation, and the constant increases along with the increasing of the temperature. The higher temperature is advantageous to the adsorption. The adsorption is an endothermic process. At the same temperature, the Polanyi adsorption potential reduces by increasing the concentrations of citric acid and tea polyphenols. At the same initial concentration, the Polanyi adsorption potential increases by increasing the temperature. The adsorption kinetics is satisfied with second-order equation. The adsorption mass transfer process is influenced and controlled by the liquid film diffusion and intraparticle diffusion. The process is mainly controlled by the intraparticle diffusion.