This invention discloses a polyethersulfone hollow
fiber nanofiltration membrane for dye / salt separation, its preparation method, and its application, belonging to the field of membrane
separation technology. This invention proposes a polyethersulfone hollow
fiber nanofiltration membrane for efficient dye / salt separation, its preparation method, and its application. Polyethersulfone and
diphenylmethane diisocyanate are dissolved in an
organic solvent to prepare a
spinning solution. Using a wet
spinning process, the
spinning solution is extruded and then sequentially immersed in a pure water coagulation bath and a compound-containing
aqueous solution coagulation bath for
phase inversion. During coagulation, the diisocyanate reacts with water to generate CO2, forming a porous structure in the
fiber. Upon entering the compound coagulation bath, the residual
isocyanate groups undergo a
condensation reaction with one end of the compound, constructing a
polyurea functional layer containing functional groups in situ on the fiber surface and the inner wall of the pores. This invention transforms byproducts from traditional wet spinning into functional components, simultaneously achieving the construction and
functional modification of the porous structure within the membrane in a one-step process. The resulting
nanofiltration membrane possesses both hydrophilicity and strong
negative charge, exhibiting a high
rejection rate for dye molecules while maintaining a low
rejection rate for
inorganic salts, thus enabling highly efficient and selective separation of dyes and salts. This preparation process is simple and highly controllable, showing promising prospects for industrial application in
textile wastewater treatment and resource recycling.