The Preparation Of The Ion Exchange Fiber Based The Porous Polyethylene And Study On Purfication Of Glycyrrhizic Acid

In the paper, we spinned the porous polyethylene fibers by melt spinning and acidification with the calcium carbonate as pore-forming agent, then we grafted the styrene onto the porous hollow polypropylene fibers in solvent method in order to get the ion exchange fiber that had high ion exchange capability. The self-made ion exchange fibers were characterized by the means of IR spectrum, SEM and TG. The ion exchange fibers were applied in the extraction and separation of glycyrrhizic acid from the liquorice; the results were good and the process conditions were feasible.The ion exchange capability of the ion exchange fibers made in the solvent method at the optimal conditions could achieve3.05mmol/g. The fiber had good adsorption to water and ethanol. The results of characterization showed that the fiber’s characteristic peaks were remarkable; the morphology change was obvious and the thermal stability was good. The performance test indicated that the fiber could meet the requirement of application.The optimal process conditions were got when the self-made strong alkali anion exchange fibers were applied to separate and purify the glycyrrhizic acid from liquorice. The process could improve the purity of glycyrrhizic acid from28.38%to78.71%so as to increase2.7times. This showed that the processes of extracting and separating the glycyrrhizic acid from liquorice were practical and feasible.Under optimal reaction conditions, the influences on the ion exchange rate including concentration of glycyrrhizic acid and temperature were investigated. Moving Boundary Model was applied to describe the kinetics of adsorption process. For the dominant procedure of exchange process through ion exchange fiber, the apparent activation energy39.84kJ/mol, reaction order1.804, rate constant9.89×10-5s-1and total kinetics equation were obtained.