Nanofiltration membranes are mostly composite membranes, consisting of three layers: Non-woven fabric base layer (~150μm) : Provides mechanical support (polyester fiber). Porous support layer (~50μm) : Polysulfone/polyethersulfone, forming a microporous structure. Ultra-thin separation layer (~0.1μm) : Polyamide, which determines the separation performance (molecular weight cut-off 100-1000 Da). The MAXIE key innovation: Surface modification of the separation layer (such as grafting negatively charged groups) to enhance the retention rate of divalent ions (Ca²⁺, SO₄²⁻).
