High temperature-resistant composite nanofiltration membrane and preparation method thereof

A method for preparing a high temperature-resistant composite nanofiltration membrane, comprising the following steps:

• mixing an amine, an inorganic salt, a silane additive, and deionized water evenly at a mass ratio of (0.5-3):(0.5-3):(0.5-3):(91-98.5) to obtain an aqueous phase solution;
• mixing a polyacyl chloride and an oil phase solvent evenly at a mass ratio of (0.05-1):(99-99.95) to obtain an oil phase solution;
• immersing a base membrane in the aqueous phase solution to obtain a primary base membrane;
• immersing the primary base membrane in the oil phase solution to obtain an immersed base membrane;
• and
• subjecting the immersed base membrane to a heat treatment to obtain the high temperature-resistant composite nanofiltration membrane;
• wherein the method further comprises a step of preparing the base membrane before immersing the base membrane, which is performed as follows:
• mixing a polyethersulfone resin, a polybenzimidazole resin, and a N-methylpyrrolidone at a mass ratio of 13:2:85 to obtain a mixture, and stirring the mixture for 4 h to 24 h under heating to obtain a uniformly-dispersed casting solution;
• subjecting the uniformly-dispersed casting solution to filtration and vacuum degassing in sequence to obtain a primary casting solution;
• coating the primary casting solution evenly onto a non-woven fabric by a membrane casting machine to form a wet membrane;
• and
• subjecting the wet membrane to pretreatment and curing in sequence to obtain the base membrane.