Method for removing residual minim chloroform from tea polyphenol

Abstract

The invention belongs to the field of chemical industry and relates to a method for removing trace residual chloroform from natural extract tea polyphenols. The method is to make the aqueous solution of tea polyphenols containing chloroform flow through the inorganic zeolite molecular sieve under normal temperature and pressure, and the liquid hourly space velocity of the aqueous solution of tea polyphenols passing through the molecular sieve is 0.5-4.0h-1. The tea polyphenols treated by the method can reach the national drinking water standard. The method is quick and convenient, low in energy consumption and treatment cost, and good in effect, and the adsorbent used is regenerated by heating to recover its adsorption performance, and can be used repeatedly. The adsorbent does not cause secondary pollution to tea polyphenol products.

Description

technical field [0001] The invention belongs to the field of chemical industry and relates to a method for removing trace residual chloroform from natural extract tea polyphenols. Background technique [0002] Tea polyphenols, also known as tea tannins and tea tannins, are the general term for polyphenols in tea. Its main component is catechin, accounting for about 80% of its total amount. Tea polyphenols have good biological functions in the elimination of free radicals, anti-oxidation and other biological activities, antibacterial, antiviral, tumor suppression, prevention and treatment of cardiovascular diseases, etc., and have been widely used in health products, food additives and medical drugs. Organic solvent extraction is one of the traditional production processes for extracting tea polyphenols. Chloroform extraction is used in the process to remove caffeine and pigments. Therefore, the extracted tea polyphenols contain trace amounts of chloroform. Chloroform is mo...

AI Technical Summary

Problems solved by technology

[0003] At present, domestic methods for removing chloroform mainly include the following: ①Activated carbon adsorption method [Fan Yanzhen et al., "Experimental research on the performance of GAC, UF, and RO to remove chloroform and carbon tetrachloride [J]", China Water Supply and Drainage. 1999, 15( 10), 9-12]: Activated carbon is easier to adsorb and remove trihalomethanes and carboxylic acids with smaller molecular weight and stronger polarity, but the adsorption performance to chloroform is poor

In order to prevent activated carbon from being saturated by adsorbed chloroform and being replaced by other coexisting organic substances from the carbon, the use time of activated carbon is limited

② Resin adsorption method [Li Yunsong et al., "Adsorption performance of XDA-1 macroporous adsorption resin on chloroform in water [J]." Resource Development and Market, 2005, 21(3): 185~201]: Porous ion exchange resin It can replace activated carbon to adsorb and remove chloroform, and use hot air thermal desorption to recover chloroform, but this method is easy to cause secondary pollution in the process of recovering chloroform and the resin regeneration is difficult and cannot be reused

However, due to the active chemical properties of tea polyphenols, which are easily oxidized, the boiling method will cause tea polyphenols to volatilize and lose their biological activity, which will seriously affect the quality of the product.

④Aeration method: The aeration method is often used to remove chloroform in water, but it needs to pass in air several times larger than the water volume. The elimination rate is not only affected by aeration time, gas flow rate, water temperature, and water volume, but also the waste of water It is also relatively large, and it is not easy to promote and use

However, how to design on-site and apply the ultrasonic reactor in actual production still needs further research and discussion.

⑥Ultrafiltration (UF) method [Fan Yanzhen et al., "Experimental research on the performance of GAC, UF, RO to remove chloroform and carbon tetrachloride [J]" China Water Supply and Drainage. 1999, 15(10), 9-12]: new UF membrane can quickly and effectively remove chloroform through physical adsorption, but the adsorption capacity is limited. When the content of chloroform in tea polyphenols is high, there are still problems of large usage of UF membrane and frequent regeneration.

[0009] (1) Currently the most effective catalyst Pd is too expensive

[0010] (2) The reducing agent or catalyst belongs to heavy metal, which is easy to cause secondary pollution of heavy metal

[0011] (3) The current multi-metal or heterogeneous catalytic systems are all carried out under higher temperature or pressure, which makes the cost of processing chloroform in tea polyphenols higher, the facilities are more complicated, and high temperature will also destroy the biological activity of the product, so it is difficult to popularize

Images