| Macroporous adsorption resins(MARs)technology is widely used in separation and purification of effective constituent in natural products because of its advantages such as high adsorption capacities,many categories,regeneration easily,low cost,adsorption selectivity and the functional groups on the surface could be designed and changed et al..Our work focuses on highly efficient separation effective constituent in natural products,purification of salicin from White Willow Barks and oleuropein from Olive Leaves by MARs,respectively.Based on the detection of High Performance Liquid Chromatography(HPLC)and adsorption/desorption experiments,the results were shown as follows:1.Fourteen kinds of MARs were investigated in separation and purification of salicin from White Willow Bark crude extract,the static adsorption/desorption performance for salicin of different MARs with different polarities have been carried out in this study firstly.Then the related theoretical research,such as adsorption/desorption kinetics and adsorption isotherm were investigated systematically based on AUKU-2 and AUKJ-1,which were chosen according to the static adsorption/desorption performance,and some useful conclusions were obtained.Results showed that the kinetics experimental data for both were fitted best to the pseudo-second-order kinetic model,and Elovich model could fit the experimental results well.The adsorption isotherms experimental data for both were fitted well with the Langmuir isotherm and the values of E obtained from Dubinin-Radushkevich isotherm model for both MARs were greater than 1 k J·mol-1 and lower than 8 k J·mol-1,which indicated the adsorption were more preferred to physical type.Besides,the further exploring of the adsorption thermodynamics results presented enthalpy change and entropy change for two above MARs were different obviously,and related directly to the adsorption/desorption performance of MARs with positive relationship,which primarily illustrated that suitable MARs could be chosen according to adsorption thermodynamics study.Finally,the separation conditions of salicin from White Willow Barks crude extract were investigated and optimized based on AUKJ-1 by dynamic adsorption/desorption experiments with the packed column form.Under the optimal conditions,salicin content increased 2.125-fold from 16 to 50% with the recovery yields of 87% through only one cycle treatment.2.Fourteen kinds of MARs were investigated in separation and purification of oleuropein from Olive Leaves extract,key parameters of the static adsorption/ desorption were researched,and BNKX-3 was chosen as the adsorbent in futher study.Kinetics and isotherms were systematically investigated according to the static adsorption experiments.It could be found that the pseudo-second-order model was more suitable to describe the adsorption kinetics than pseudo-first-order model,which explained that the adsorption process of MAR for oleuropein was the diffusion controlled mainly.According to the fitting results of particle diffusion model,the adsorption process was saturated in the surface at first,and then diffused to the inner.The Elovich model illustrated the adsorption process possessed a great change of activation energy.The adsorption isotherm of BNKX-3 for oleuropein was conformed to Brunauer ?,which was the characteristic adsorption curve of mesoporous,and it was coincided with the results of BET.After the adsorption process,desorption experiments with different desorption solutions were evaluated,and acetone or ethyl acetate with different ratios were added into 95% ethanol,the desorption capacities and desorption ratios were evaluated in this case.MARs in different solvent systems would swell,and the swelling effect may play an important role in desorption process.This method could evaluate the polarity of MARs depended on the value of Log P for different desorption solutions. |
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