Abstract
An improved photocatalytic microfiltration membrane was successfully prepared by the impregnation method with nitrogen-doped TiO2/graphene oxide (GO) (NTG). By utilizing the unique role of N and GO, the photocatalytic activity of the membrane in UV and sunlight was improved. Compared with the Polyvinylidene Fluoride (PVDF) microfiltration membrane which was modified by TiO2, N-TiO2 (NT) and TiO2-GO (TG), the NTG/PVDF membrane exhibited high photocatalytic efficiency and significantly improved photodegradation power to the methylene blue (MB) solution under ultraviolet light and sunlight, with the photocatalytic efficiency reaching 86.5% and 80.6%, respectively. Scanning electron microscopy (SEM), X-ray diffractometry (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to analyze the morphology, crystal structure and chemical bonds of the membrane surface. The hydrophilicity of the modified PVDF microfiltration membrane was significantly improved, the flux of the pure water membrane reached 1672 Lm−2h−1, the flux of the MB solution was also significantly improved due to photodegradation. Therefore, the nitrogen-doped titanium dioxide graphene oxide PVDF microfiltration membrane (NTG/PVDF membrane) has great development prospects in sustainable water treatment.
Highlights
Membrane separation is a promising separation and purification technology for pollutants
The Polyvinylidene Fluoride (PVDF) microfiltration membrane was immersed in deionized water for 0.5 h, the membrane was immersed in the prepared KMnO4 (3%) and NaOH (3 mol/L) solution
Photodegradation of the membraneswas were significantly than the TiO. This is because modifiedimproves photocatalytic composite membranes
Summary
Membrane separation is a promising separation and purification technology for pollutants. The bulk modification method has a limited hydrophilic effect, it makes it difficult to disperse the modifier, has a low photocatalytic activity and causes the physical-chemical properties to be prone to change. The surface modification hydrophilic effect is a significant improvement from this as it does not affect the physical-chemical properties of the membrane body and the modified membrane exhibits excellent photocatalytic properties [16]. The surface modification of the ultrafiltration membrane by TiO2 /GO was discussed and the results showed that the photodegradation performance of the modified membrane was improved but that the modification process was slightly complicated [3,17]. The PVDF microfiltration membrane was modified by the surface coating method with nitrogen-doped TiO2 /GO composites. The morphology, crystal structure, hydrophilicity, surface functional groups, membrane flux, photodegradation kinetics and the effects of different light conditions on the degradation of photocatalytic membranes were analyzed
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