| The major drawback of the conventional ultrafiltration membranes is their hydrophobic in nature. Also in general membranes suffer from fouling and hence lead to low membrane life time. Nanomaterial-polymer hybrid membranes have been intensively studied in recent years due to their superior properties, such as strong mechanical strength, high thermal stability, excellent permeability and selectivity. Among various nanomaterial, graphene and its derivative graphene oxide(GO), single-atom thick and two-dimensional materials, have attracted great attention for their remarkable electronic, mechanical and thermal properties. This paper aimed to fabricate high-performance polymer/GO membranes using different methods and systematically investigate the effect of GO nanosheets on the morphology, surface property, mechanical strength and separation property of the polymer/GO hybrid membranes. The synthesized membranes were characterized by scanning electron microscopy(SEM), Transmission Electron Microscope(TEM), Atomic Force Microscope(AFM), Fourier transform infrared spectroscopy(FTIR), Raman spectrua(Raman), X-ray photoelectron spectroscopy(XPS), X-ray diffraction(XRD), contact angle goniometry, tensile strength measurement, etc. The main conclusions are as follow:(1) Dynamic models of the water transport of polymer/graphene oxide hybrid membranes were estabilished.(2) Polysulfone/Graphene Oxide( PS/GO) membranes synthesized in a GO containing water coagulation bath via phase inversion process. When compared to the neat PS membrane, the fluxes of the PS/GO-5, PS/GO-10 and PS/GO-20 membrane decreased by 35.3%, 68.4% and 75.1%, respectively. The rejection rates of the PS/GO membranes were slightly lower than PS membrane due to formation of some large pores. Moreover, the PS/GO membranes exhibited better mechanical strength although membrane integrity was destroyed to some extent due to the incorporation of GO nanosheets.(3) Four Polyvinylidene Fluoride / Graphene Oxide( PVDF/GO) membranes synthesized by the casting solutions prepared at 50, 70, 85 and 100 °C, which were denoted PVDF/GO-50, PVDF/GO-70, PVDF/GO-85 and PVDF/GO-100, respectively. X-Ray Photoelectron Spectrometer(XPS) and Raman Spectroscopy results showed that higher preparation temperature resulted in a higher degree reduction of GO nanosheets. Compared with the pure PVDF membrane, PVDF/GO membranes achieved better performance in term of membrane flux and rejection. These properties were influenced by both the reduction degree and GO loading. The agglomeration of GO nanosheets at high reduction degree and GO loading in PVDF/GO membranes needs to be overcomed to further improve the performance of PVDF/GO membranes.(4) A new simple method was developed to fabricated brominated poly(phenylene oxide) /graphene oxide( BPPO/GO) hybrid membrane by crosslink GO to the surface of BPPO membrane. With the increase of GO loading, the flux of the BPPO/GO membrane decreased and the rejection increased. However, there is no significantly change when the GO loading increased to higher than 65 mg/m2. The stability of the BPPO/GO hybrid membranes was tested by comparing the membrane performance one month later, results showed the one month later membrane performance is around 90% of the previous performance. Compared to the control membrane, the hybrid membranes have a better antifouling and antibacterial property. Conclusions are useful for the developing of polymer/graphene oxide membranes. These results are also important and practical for the application of polymer/graphene oxide membranes in water application. |
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