Eco-friendly fabrication of porphyrin@hyperbranched polyamide-amine@phytic acid/PVDF membrane for superior oil-water separation and dye degradation

The treatment of oily wastewater containing water-soluble dyes has drawn attention and become a thorny issue. Aiming at removing oil droplets and dyes from wastewater, it is reported in this work the design of poly -electrolyte deposited dual functional membrane with superior separation and degradation capabilities. The hyperbranched polyamide-amine (HPAMAM) was combined with tetra (4-carboxyphenyl) porphyrin (TCPP) and phytic acid (PA) through electrostatic interaction to form an eco-friendly polyelectrolyte complex by one-step self-assembly method. Relying on affluent amine group and unique cavity structure as well as wide range of delocalized pi-electron systems, TCPP@HPAMAM@PA possesses robust water binding ability and intense ab-sorption in the visible region, endowing PVDF membrane with superhydrophilicity/underwater super-oleophobicity, oil resistance and superior photocatalytic degradation properties. The dual functional TCPP@HPAMAM@PA/PVDF membranes can realize superb removal of oil droplets (oil rejection > 99 %) at high flux recovery rate with several cycles. Furthermore, the degradation efficiency of rhodamine B (RhB) and Methyl blue (MB) reaches 93 % and 96 % respectively, showing standout photocatalytic degradation performance. A facile and low-energy strategy for the modification of commercial PVDF membranes is proposed, which is not only consistent with the concept of green chemistry but also has a broad application in the separation of complex oily wastewater systems.