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Novel hollow fibre polysulphone (PSF) separation membranes were prepared via the incorporation of carboxylated graphene oxide (cGO) in membrane matrix during the dry‐wet spinning process to improve the membrane performance of water flux and dye adsorption. The surface composition and morphology of the prepared cGO‐incorporated hollow fibre membranes were characterised by means of Fourier Transform–infrared spectra and scanning electron microscopy. The effects of different cGO contents on membrane surface hydrophilicity, separation performance, anti‐compaction and adsorption properties were investigated through measurements of the water contact angle, cross‐flow filtration and methylene blue (MB) adsorption experiments. The results demonstrated that the cGO‐incorporated membranes had more hydrophilic surfaces, higher permeation flux, better anti‐compaction properties and a higher adsorption rate of MB than that of the PSF control membrane. When cGO content was 0.45 wt.%, the pure water flux of the modified membrane increased from 90.56 to 148.26 l m−2 h−1 at 0.1 MPa; also, rejections of bovine serum albumin and polyethylene glycol (PEG‐20000) maintained relatively high values of 98.81 and 93.89%, respectively. The incorporation of cGO nanosheets could effectively improve membrane anti‐compaction properties and the adsorption rate of MB. [ABSTRACT FROM AUTHOR]

Potato starch wastewater contains high-concentration potato proteins which have great potential in the fields of food and health care. Most researches on potato protein recovery by membrane separation technique are focused on flat sheet or tubular ultrafiltration (UF) and reverse osmosis (RO) membranes and lack the further protein purification and the in-depth discussions on the fouling behavior. In this laboratory-scale study, potato proteins were recovered and purified from the simulated potato starch wastewater by the self-made hollow fiber (HF) UF and nanofiltration (NF) separation membrane integrated process. 85.62% potato proteins with high molecular weight in the potato starch wastewater could be retained by UF membrane and 92.1% potato proteins with low molecular weight were rejected by NF membrane. The concentrated solution after UF and NF filtration was desalinated and purified by diluting the solution eight times and filtering the diluted solution with UF membrane. Both types of HF membranes, UF and NF, suffered the inevitable membrane fouling. After the traditional physical washing and chemical cleaning, water flux of UF and NF membranes can be effectively recovered. The corresponding recovery rates of UF and NF membranes can reach 93.5% and 84.7%, respectively. The hollow fiber UF-NF separation membrane integrated process was proved to be a promising technique of high-purity potato protein recovery from potato starch wastewater. Unlabelled Image • Potato protein was recovered and purified from potato starch wastewater. • Hollow fiber UF-NF separation membrane integrated process was employed. • The recovery rate of potato protein could reach 92.1%. • Membrane water flux could be effectively recovered after appropriate cleaning. [ABSTRACT FROM AUTHOR]

In order to obtain the compatible poly(p‐phenylene terephthalamide) (PPTA)/polyvinylidene fluoride (PVDF) blend membranes, the casting solution was synthesized via the in situ polycondensation process and flat sheet blend membranes were successfully prepared through the immersion precipitation phase inversion method in our previous study. In this study, the polycondensation solution was directly used as the spinning dope to fabricate PPTA/PVDF hollow fiber in‐situ blend membrane by the dry‐wet spinning technique. Hollow fiber membranes were employed to remove the dyes including Congo red (CR) and methylene blue (MB) from the dyeing liquor. Effects of operation conditions on dye rejection and membrane water flux were investigated. With the increase of operation pressure, feed concentration and feed temperature, dye rejection rates gradually decreased, but the rejection value of CR and MB still remained above 99.5%. On the contrary, the permeation water flux basically increased. During the continuous dye filtration of 300 min, hollow fiber membrane can maintain high dye rejection rates and stable water flux. The combination method of physical backwashing and chemical cleaning can effectively alleviate membrane fouling and recover membrane water flux. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020, 137, 48569. [ABSTRACT FROM AUTHOR]

Schematic diagrams of different nanofibrous layers and water droplet contact on layer surface. (a) pristine PVDF nanofibrous layer; (b) FTES-GO incorporated PVDF nanofibrous layer. • Hydrophobic nanofibrous composites for MD were prepared via electrospinning technique. • FTES functionalized GO nanosheets were incorporated in the PVDF nanofibrous layers. • Surface hydrophobicity and water permeability were improved. • No obvious wetting phenomenon was observed. Hydrophobic nanofibers have attracted great attention in the membrane distillation (MD) process because of their extremely high specific surface area. In this study, hydrophobic nanofibrous composites for vacuum membrane distillation (VMD) consisting of a hydrophobic polyvinylidene fluoride (PVDF) nanofibrous layer and a hydrophobic polypropylene (PP) nonwoven fabric (NWF) substrate were presented. PVDF nanofibrous layer was directly fabricated on the surface of PP NWF substrate by electrospinning technique. 1 H , 1 H , 2 H , 2 H -perfluorooctyltriethoxysilane (FTES) functionalized GO nanosheets were incorporated in the PVDF nanofiber layer during the electrospinning process to enhance the hydrophobicity and permeation water flux for VMD. Membrane surface morphology and composition were characterized through SEM and FTIR. The effects of FTES-GO nanosheets content on the VMD desalination properties were investigated. And the transfer mechanism of water vapors through the FTES-GO incorporated nanofibrous layers was also proposed. Compared with the original PVDF nanofibrous layer, the surface hydrophobicity, liquid entry pressure (LEP) and water permeability of the FTES-GO incorporated nanofibrous layers had all been improved. When FTES-GO content was 4 wt%, the WCA increased from 104.0° for the neat PVDF nanofibrous layer to 140.5° for the modified nanofibrous layer. The permeation water flux reached a maximum value of 36.4 kg m−2 h−1. It was two times the water flux of the original membrane and meanwhile the salt rejection remained above 99.9% (50 °C, 3.5 wt% NaCl aqueous solution and permeation pressure of 31.3 kPa). No obvious wetting phenomenon was observed for FTES-GO incorporated membrane during the continuous VMD experiment for 60 h. [ABSTRACT FROM AUTHOR]

Unlabelled Image • Tobacco protein was extracted by hollow fiber membrane integrated process. • Derived wastewater was treated harmlessly by hollow fiber RO membrane. • The recovery rate of tobacco protein could reach 93.1%. • Membrane water flux could obtain effective recovery after combined cleaning. [ABSTRACT FROM AUTHOR]