Study On The Adsorption Of Panax Notoginseng Saponins And Cytisine By Rosin-Based Macroporous Resin

Natural products have high activity and are widely used in medicine,health care and food additives,so the separation of effective components in natural products has been a research hotspot.In this paper,using rosin-based cross-linking agent as skeleton,three kinds of rosin-based macroporous adsorption resins with carboxyl group,ester group and hydroxyl group were prepared,and the resin was applied to the separation and purification of Panax notoginseng saponins and cytisine.To explore the adsorption mechanism of rosin-based macroporous resin for Panax notoginseng saponins and cytisine,and expand the application value of rosin resources.（1）The resins RM131,RM132 and RM136 with three different groups（carboxyl,ester and hydroxyl）were prepared by suspension polymerization of ethylene glycol maleopimaric acid（EGMRA）with three monomers of methacrylic acid（MAA）,methyl methacrylate（MMA）and hydroxyethyl methacrylate（HEMA）.The resin was characterized by measuring water content,mechanical strength,particle size distribution,BET,SEM and TG.The results showed that the three resins had uniform particle size,high mechanical strength,high water content,rich internal and external pore structure and good thermal stability.（2）By comparing the adsorption capacity,adsorption rate and desorption rate of Panax notoginseng saponins by RM131,RM132 and RM136 resins,the RM131 rosin-based resin with excellent adsorption effect was selected.The static adsorption method was used to study the effects of four single factors:initial concentration of Panax notoginseng saponins,the dosage of RM131,temperature and time on the adsorption process.The results showed that when the temperature was 298 K,the dosage of RM131 was 0.5 g,the initial concentration of Panax notoginseng saponins was 5 mg·m L^-1,the adsorption time was 20 h,and the saturated adsorption capacity of the resin was 33.5 mg.When 40%ethanol solution was used as desorption solution,the purity of Panax notoginseng saponins was up to 74.56%,which was 2.01times higher than that of crude extract;the regeneration performance evaluation experiment of resin showed that after RM131 cycling adsorption and desorption of Panax notoginseng saponins for 10 times,the resin adsorption capacity was stable and had good regeneration ability;the cytotoxicity experiments of RM131 and commercial resin D-101 showed that RM131 was green and pollution-free.（3）The adsorption mechanism of RM131 on Panax notoginseng saponins was analyzed.The experimental results show that quasi-second-order kinetic model and Langmuir isotherm model are more suitable to describe the adsorption process of RM131 to Panax notoginseng saponins.The active site of RM131 determines the adsorption rate of Panax notoginseng saponins,and the adsorption process is uniform monolayer adsorption.The adsorption thermodynamics data show that the adsorption of Panax notoginseng saponins by RM131 is a disordered spontaneous endothermic process,and the values ofΔH andΔG belong to the range of hydrogen bond.The hydrogen bonding mode and energy calculation of three rosin based resins RM131,RM132 and RM136 on Panax notoginseng saponins R1 were analyzed by density functional theory（DFT）.The results showed that the order of hydrogen bonding forces was RM131>RM136>RM132,which corresponds to the experimental adsorption capacity,which proved that the adsorption force of RM131 to Panax notoginseng saponins was mainly hydrogen bonding.（4）By comparing the adsorption capacity,adsorption rate and desorption rate of RM131,RM132,RM136 and six commercial macroporous resins HPD100,D4020,AB-8,NKA-9,X-5 and D101 for cytisine,the RM131 rosin based macroporous resin with excellent adsorption effect for cytisine was selected.The static adsorption method was used to study the effects of the dosage of RM131,temperature,time and p H on the adsorption process.The results showed that when the temperature was 298 K,the dosage of RM131was 0.3 g,the initial concentration of cytisine was 0.14 mg·m L^-1,p H was 8.4,the adsorption time was 800 min,and the saturated adsorption capacity of RM131 was 7.51 mg.When the hydrochloric acid solution of p H=3 was used as desorption solution,the purity of cytisine increased from 68.19%to 96.15%,and the purification effect of RM131 was better than that of six commercial resins.The evaluation experiment of the regeneration performance of the resin showed that there was no difference in the adsorption capacity of the resin after RM131 cycle adsorption and desorption of cytisine for 10 times.The cytotoxicity comparison between RM131 and six commercial resins showed that RM131 resin was greener and more environmentally friendly than the commercial resins for the separation of alkaloids in the market.（5）The adsorption mechanism of RM131 on the adsorption of cytisine was analyzed,and the results showed that the adsorption amount increased with the increase of p H value,indicating that electrostatic gravity may be the main adsorption force in the adsorption process,and the quasi-second-order kinetic model and Langmuir model are more suitable to describe the adsorption process of RM131 to cytisine,the distribution of surface active sites on the resin is uniform,and there is a molecular structure force between the groups on RM131 resin and cytisine.The intra-particle diffusion model and Boyd liquid film diffusion model prove that the adsorption process is affected by liquid film diffusion,intra-particle diffusion and intermolecular force,and thermodynamic experiments show that the adsorption is a disordered and spontaneous endothermic process.Through the analysis of infrared spectrum and X-ray photoelectron spectroscopy,it is known that the-COOH group on RM131 resin is the main group in the adsorption process,and the electrostatic gravity is further determined as the main adsorption force.