A special separation membrane for dye desalting and refining

Abstract

The invention discloses a high-molecular composite membrane and particularly relates to a special separating membrane with a dye desalting refining function. The special separating membrane comprises a non-woven cloth layer, a micropore supporting layer and a function separating layer, wherein a charge screening layer is sprayed on the function separating layer and is obtained by spraying an aqueous solution of an electropositive functional material and drying. The special separating membrane disclosed by the invention has the advantages that not only can micropores in the surface of the special separating membrane be guaranteed as nano structures, but also water-soluble dye molecules with the molecular weight being more than 200 can be effectively intercepted; and simultaneously, the electronegativity of the surface of a conventional membrane is screened, the charge repulsion action between the surface of the special separating membrane and a high-value inorganic salt is reduced and most part of the water-soluble dye molecules penetrate through the special separating membrane, so that the purpose of separating the water-soluble dye molecules and the high-value inorganic salt is achieved.

Description

technical field [0001] The invention relates to a polymer composite membrane, in particular to a special separation membrane with the function of desalting and refining dyes. Background technique [0002] my country is the world's largest producer and consumer of dyes. By 2000, the total production of various dyes had reached 500,000 tons. Due to the complexity of the reaction in the synthesis of dyes, there are a large amount of inorganic salts in addition to the finished dyes in the synthetic slurry. The presence of inorganic salts will not only affect the stability of dyes, but also reduce the coloring strength and color fastness of dyes. Therefore, how to economically and effectively remove the salt in crude dyes has always been a hot spot in the research of the dye industry. [0003] Traditional dye purification is a method of salting out, filtration and crystallization. This method has complex processes, many steps, consumes a lot of salt, and the yield of dye is onl...

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Problems solved by technology

[0005] However, the nanofiltration membranes currently on the market have a relatively high rejection rate for organic substances with a molecular weight greater than 200, and also have a relatively high rejection rate for high-priced inorganic salts (such as sodium sulfate, sodium phosphate, etc.)

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