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Five factors for the application of polyamide resin in the field of separation and extraction

Jun 04, 2020

There are:

(1) It is related to how many groups of flavonoid molecules re-form hydrogen bonds, and the more groups that can form hydrogen bonds, the stronger the adsorption force;

(2) It is related to the position of the hydrogen bonding group. If the position is easy to form intramolecular hydrogen bonds, the adsorption capacity is reduced.

(3) The higher the degree of intra-molecular aromatization and the more conjugated double bonds, the stronger the adsorption.

(4) The adsorption order of different types of flavonoids is: flavonol>flavonoid>dihydroflavonol>isoflavone.

(5) It is related to the solvent medium. The ability to form hydrogen bonds in water is strong, the adsorption is strong, but it is weak in organic solvents, strong in acidic solvents, weak in alkaline solvents, so the elution ability of various solvents on the polyamide column is from weak to strong The order is: water <methanol or ethanol (concentration from low to high) <acetone <dilute aqueous sodium hydroxide solution or ammonia <formamide <dimethyl formamide <urea aqueous solution. Bai Yun'e [2] and others have used polyamide www.zhlzw.com to conduct a series of studies on the separation of total flavonoids in Trollius chinensis, comparing the adsorption and desorption amounts of total flavonoids in Trollius chinensis with 3 bell polyamides. As a result, it was found that the adsorption and desorption of the total flavonoids of Trollius chinensis using 60-80 mesh polyamide are better. [3] Using the principle of polyamide adsorption of anthraquinone through hydrogen bonding, using polyamide as the adsorption separation resin, the amount of adsorption of polyamide to Polygonum cuspidatum anthraquinone, static adsorption kinetics and isothermal adsorption and desorption properties were investigated. The comparison of desorption ability and speed proves that polyamide as an anthraquinone is superior to activated carbon and silica gel. Polyamide has an adsorption rate of 87.8% for anthraquinone, the adsorption rate control step is liquid membrane diffusion control, and the ethanol eluent has an elution rate of more than 85%. From thermodynamics, the adsorption behavior of anthraquinone on polyamide is a multilayer adsorption mainly based on single layer adsorption, and the principle of adsorption is obtained: single layer adsorption includes chemical adsorption and physical adsorption, and multilayer adsorption is mainly physical adsorption.