Study On Coupling Technology Of Membrane Filtration And Modified Activated Carbon Adsorption For High Purified Tannic Acid

Tannic acid extracted from natural resources has a close relationship to daily life. From50s 20 century, with the deep development of characters of tannin, Tannic acid shows broadapplication prospects and plays a great role in national economy. The coupling technology ofmembrane filtration and modified activated carbon column absorption for preparing highputified tannic acid used in the fields of biochemistry, medicine and food industry etc wasstudied. The obtained process successfully promoted the quality of tannic acid which reachedabove 99ï¼…in content, 82.8ï¼…at yield, and about 300ppb in content of metallic ion. The moreimportant thing is that it provides the theoretical support and viable technique for industrialproduction.In this paper, high purified tannic acid was successfully prepared on the methods ofultrafiltration(UF), nanofiltration(NF) and innovative modified active carbon columnabsorption technology which were the most advanced technology in the field of natural productpurification.The route of tannic acid purification was established including pretreatment, modifiedactivated carbon column absorption and UF and NF. In the first part of paper, current researchbackground and situation of high-quality tannic acid and industrial application of UF, NF wasdiscussed; the second chapter introduced the tannic acid content and the molecular weightdistribution and the metallic ions content analysis methods as well as instruments; the route ofpretreatment of industrial tannic acid was established in the third part of paper; in chapter four,two ways of modification of activated carbon and column absorption experiment wereinvestigated in order to remove metallic ions from tannic acid; in chapter five, membraneequipments and membrane separation process were investigated followed by the couplingexperiment of membrane separation and modified activated carbon column absorption.The main research results were as follows:(1) The high-yield pretreatment process of tannic acid was determined. Tannic acid can reachas high as 82.8ï¼…at yield by the method of absorption of diatomite and filteraid and thenextraction by ethyl acetate at micro-boiling state.(2) Activated carbon was modified in a creative way by the reaction with acidic and alkaline active substances respectively after oxidation in order to promote the capacity of removingmetallic ions from tannic acid. At the same time column mode was applied which wasbeneficial to modified activated carbon absorption.(3) It was the first time to apply the membrane separation technology for tannic acidpurification, and the membrane separation process was determined.(4) In this paper, coupling technology was applied replacing conventional separationmethods. As a result, advanced tannic acid reached above 99ï¼…in content, 72.7ï¼…at yield, andthe content of metallic ions of Ca²⁺, Fe³⁺, Na⁺ were 333 ppb,243ppb, 127ppb respectively.