The invention discloses a preparation method of an ultrahigh-flux composite
nanofiltration membrane. The preparation method comprises the following steps: blending
hyperbranched polyester molecules with a special molecular structure and
piperazine molecules to obtain a composite water-phase
monomer solution with synergistic reaction capacity, and then carrying out controllable
interfacial polymerization reaction on the composite water-phase
monomer solution and multi-element
acyl chloride on a support layer, and forming an active separation layer with a special
structure and function. The introduction of
hyperbranched polyester molecules controls the
polymerization reaction of
piperazine and multi-element
acyl chloride by influencing the interface characteristics on one hand, and enables a large number of primary hydroxyl groups contained on the molecular surface to participate in
polymerization on the other hand; therefore, a two-
branch circular structure and nano-scale pore channels in molecules are anchored in an active separation layer in a
covalent bond manner, so that the ultra-thin and smooth ultra-high-flux composite
nanofiltration membrane with strong
permeation selectivity is generated. The method is simple and convenient to operate, low in cost, wide in
raw material source and easy to realize industrial production.