Synthesis of Ag-SiO2-APTES Nanocomposites by Blending Poly(Vinylidene Fluoride) Membrane with Potential Applications on Dye Wastewater Treatment

In the study, the Ag-SiO2-APTES nanocomposite was synthesized via the self-assembly method to prepare Ag-SiO2 and subsequently used 3-aminopropyltriethoxysilane (APTES) to functionalize its surface. The as-prepared Ag-SiO2-APTES nanocomposite was embedded into poly (vinylidene fluoride) (PVDF) membrane by the co-blending way to fabricate the Ag-SiO2-APTES membrane. The Ag-SiO2-APTES nanocomposites were characterized by X-ray diffraction (XRD). These membrane materials were characterized by field emission scanning electron microscopy (SEM), transmission electron microscopy (TEM) and FT-IR spectra. The performance of membrane was investigated simultaneously for removing the organic dye methylene blue (MB), Rhodamine B, Direct Red 28 and anti-microbial ability. The experimental results demonstrated that the Ag-SiO2-APTES modified membrane were presented to be more hydrophilic with a contact angle 55.6 degrees, whereas the pristine PVDF membrane was 81.8 degrees. The dye rejection ratios were also improved after adding Ag-SiO2-APTES, which reached 86.8% for MB, 87% Rhodamine B, 88% for Direct Red 28, besides, the removal rate of MB was about 98.7% at pH = 11. More importantly, the Ag-SiO2-APTES membranes exhibited excellent antifouling properties for treating MB solution and could reach 85% of flux recovery ratio after four cyclic experiment. Finally, via inhibition zone method of antimicrobial test Ag-SiO2-APTES membrane exhibited the antimicrobial activity against Escherichia coli (E. coli) excellently. The novel antifouling and antibacterial Ag-SiO2-APTES membrane has a potential for dye wastewater treatment and water purity.