Preparation method for monoamine-grafted-and-modified crosslinked polyimide solvent-resistant nanofiltration membrane

The invention provides a preparation method for a monoamine-grafted-and-modified crosslinked polyimide solvent-resistant nanofiltration membrane. The preparation method comprises the following steps: a, preparing a mixed solution from a solvent and a cosolvent according to a mass ratio of 1: 0.1-5; b, adding 15 to 28% of a polyimide solution into the mixed solution so as to prepare a membrane casting liquid; c, adding 2.5 to 20% of monoamine into the membrane casting liquid and carrying out mixing at 25 to 80 DEG C for 3 to 24 h under stirring so as to guarantee complete grafting; d, preparing a membrane by using a immersion-precipitation phases inversion process, washing the prepared membrane with deionized water a plurality of times and standing the washed membrane for subsequent usage; e, preparing an alcoholic solution of diamine with a concentration of 0.5 to 20%; f, putting the prepared membrane in the alcoholic solution of diamine prepared in the previous step for crosslinking modification for 0.25 to 48 h; and g, after completion of the reaction, soaking and cleaning the membrane in an alcohol solvent so as to obtain the polyamide nanofiltration membrane with excellent performance. The polyimide solvent-resistant nanofiltration membrane prepared in the invention has the advantages of simple preparation, adjustable hydrophilicity, outstanding solvent resistance, great permeation flux, a high retention rate, etc. and is applicable to separation of substances in all the organic solvents and to the fields of pharmaceutical manufacturing, biology, catalyst recovery, etc.