A catechol-based biomimetic strategy combined with surface mineralization to enhance hydrophilicity and anti-fouling property of PTFE flat membrane

To improve hydrophilicity and anti-fouling property of the polytetrafluoroethylene (PTFE) flat microfiltration (MF) membrane, a facile method was developed to modify the membrane via the co-deposition of catechol (CA) and polyethyleneimine (PEI) followed by surface mineralization of γ-(2,3-epoxypropoxy) propytrimethoxysilane (KH560). The surface chemical composition, surface morphology, hydrophilicity and filtration performance of the PTFE flat membrane were investigated by ATR-FTIR, XPS, FESEM, WCA and pure water flux measurements, respectively. After using this low-cost and simple modification method, the PTFE flat membrane was endowed with excellent hydrophilicity, high water permeation flux and superior anti-fouling property. Then, the oil/water separation tests were conducted using the modified PTFE flat membranes. The size distribution of the oil droplets is between 0.12-1.44 µm and the mean pore size of pristine PTFE flat MF membrane is 0.22 µm. The as-prepared hydrophilized PTFE flat membranes possess an excellent oil resistant ability with oil rejection ratio near 99%. Finally, the surface stability of the modified membrane was studied and the mineralized membrane showed excellent acid resistant ability. Therefore, this facile strategy holds attractive potential practical application in water environmental remediation.