Preparation method and application of in-situ secondary interfacial polymerization hydrophilic modified ultrathin composite membrane

The invention provides a preparation method and application of an in-situ secondary interfacial polymerization hydrophilic modified ultrathin composite membrane, and belongs to the technical field of membrane preparation and separation, and the preparation method comprises the following preparation steps: taking a polyacrylonitrile ultrafiltration membrane as a porous support base membrane, and carrying out in-situ amination treatment on the surface of the porous support base membrane to obtain the in-situ secondary interfacial polymerization hydrophilic modified ultrathin composite membrane. The preparation method comprises the following steps: preparing an aminated support base membrane, soaking the aminated support base membrane in a multi-acyl chloride organic phase solution to carry out primary interfacial polymerization reaction, soaking the membrane in a water phase solution containing a hydrophilic material to carry out secondary interfacial polymerization reaction, and carrying out heat treatment to