Investigation On Polyvinylidene Fluoride Hybrid Membranes Filled Y_xFe_yZr_1-x-yO₂ Solid Super Acid Coated TiO₂ Nanotubes

In this paper,in order to further enhance the properties of polyvinylidene fluoride（PVDF）membrane,such as mechanical,hydrophilicity,anti-compaction and anti-fouling performance,Y_xFe_yZr_1-x-yO₂ solid superacid coated TiO₂ nanotube（SYFZr-TiNs）were dopped into PVDF to prepare SYFZr-TiNs/PVDF hybrid membranes with micro reaction locations（MRLs）inside channels and surface of membranes.The research has important theoretical value and practical significance.Firstly,Y_xFe_yZr_1-x-yO₂ solid superacid coated TiO₂ nanotube（SYFZr-TiNs）were prepared by preparation of TiO₂ nanotube,coating of Y_xFe_yZr_1-x-yO₂ solid superacid and modification by sodium dodecyl benzene sulfonate（SDBS）.SYFZr-TiNs were characterized by Fourier transform infrared（FT-IR）,scanning electron microscope（SEM）,X-ray diffraction（XRD）,BET and acidity measurement.Secondly,SYFZr-TiNs were dopped into PVDF to prepare SYFZr-TiNs/PVDF hybrid membranes（the appropriate mass ratio of SYFZr-TiNs:PVDF is 10:100（g:g））.SYFZr-TiNs/PVDF hybrid membranes were studied by Fourier transform infrared（FT-IR）,scanning electron microscope（SEM）,the contact angle of water,tensile strength,porosity,et al.Thirdly,SYFZr-TiNs/PVDF hybrid membranes were used for treating seawater containing oil and the stability of the hybrid membranes were studied.Lastly,interaction mechanism between SYFZr-TiNs and PVDF chains were analyzed.The results show that the length of SYFZr-TiNs is about 1.8 μm,diameter is about 100 nm,the ratio of length to diameter is about 18;the surface of SYFZr-TiNs have abundant hydroxyl,Y and Fe have been doped into the lattice of ZrO₂ sucessfully,and the doping of Y stabilizes the crystal type of Zr O₂,acidity of SYFZr-TiNs is-16.468.SYFZr-TiNs are uniformly dispersed inside SYFZr-TiNs/PVDF composite membranes and interact with PVDF chains by hydrogen bonds.The contact angle of SYFZr-TiNs/PVDF hybrid membranes is declined from 67.6 ° to 36.0 °,tensile strength is improved from 1.23 MPa to 3.73 MPa,porosity is 71.89%.The water quality of seawater containing oil treated by SYFZr-TiNs/PVDF hybrid membranes is:turbidity:0.16 NTU,oil concentration:2.41mg/L,COD: 51 mg/L,SS:2.8mg/L,under the conditions of wastewater temperature 25°C and trans-membrane operationpressure 0.15 MPa,which meets A3 level standard of clastic rock reservoir water flooding and first level of Tianjin municipal sewage comprehensive discharge.The performance of SYFZr-TiNs/PVDF hybrid membrane is stable in the long-term preservation.The tubular structure,photodegradation performance and solid superacid property of SYFZr-TiNs micro reaction locations（MRLs）inside channels and surface of PVDF membrane,which can partially broke down organic pollutants,inorganic oxide particles and microbes.Therefore,the mechanical,hydrophilicity,anti-compaction and anti-fouling properties of PVDF membranes are improved by doping SYFZr-TiNs,and SYFZr-TiNs/PVDF hybrid membranes are desirable for treating seawater containing oil.