•A facile technique was developed to fabricate super-hydrophilic PVDF based membrane.•Fabrication produced highly antifouling, hydrophilic and photocatalytic membrane.•Excellent performance reflected TiO2 NPs both on membrane surface and in its matrix.•Consistency in membrane performance was confirmed with three sequential batch runs.The hydrophilicity of PVDF membrane is playing an enormously important role in its widespread water treatment fields considering the excellent intrinsic properties of PVDF raw materials. Rather than the conventional surface modification or hybridization, herein, we report a novel approach to prepare super-hydrophilic PVDF ultrafiltration (UF) membrane by creating a prefabricated super-hydrophilic surface of inorganic TiO2 nanoparticles (NPs). The resultant membrane [prepared by prefabrication surface adhesion of TiO2 NPs on PVDF-PEG-TiO2 hybrid membrane (SaT-PPT)] has a uniform distribution of TiO2 NPs not only on the membrane surface but also within membrane matrix, this will maximize the super-hydrophilic feature throughout the membrane: from inner porous structures to outer surfaces, and will avoid “dead-corner” to block fast water pass through. The performances of SaT-PPT membrane as compared with the control membranes (PVDF-PEG, and PVDF-PEG with TiO2 anchored only at surface) were investigated in terms of humic acid (HA) rejection, flux and flux decline in lab-made cross flow UF experiments with and without UV irradiation. It indicated that SaT-PPT membrane exhibited the highest hydrophilicity and flux, lowest flux decline and total resistance, but still with the highest HA rejection rate. In addition, SaT-PPT membrane showed the highest flux recovery after simple physical cleaning to extend the longer life span of membrane. It is reasonable to believe that our developed SaT-PPT membranes will provide insightful engineering practices to benefit the broad water treatment applications.Download high-res image (301KB)Download full-size image

•A novel EMBR was developed to achieve phenol biodegradation and salt separation.•Phenol was degraded in nitrification, denitrification and other biological process.•Bacterial EPS release was related with the absorption and biodegradation of phenol.•Diversity and abundance of microbial community decreased with phenol increase.An extractive membrane bioreactor (EMBR) for phenol-laden saline wastewater was set up in this study to investigate the variations of phenol removal, extracellular polymeric substance (EPS) release and microbial community dynamics. The gradual release of phenol and the total separation of salt were achieved by silicon rubber tube membrane. Only phenol (55.6–273.9 mg/L) was extracted into microorganism unit from wastewaters containing 1.0–5.0 g/L phenol and 35.0 g/L NaCl. After 82 d of EMBR operation, maximal 273.9 mg/L of phenol was removed in EMBR. Low concentration of phenol in wastewater (2.5 g/L) played a favorable effect on the microbial community structure, community and dynamics. The enumeration of Proteobacteria (30,499 sequences) significantly increased with more released EPS (82.82 mg/gSS) to absorb and degrade phenol, compared to the virgin data without phenol addition. However, high concentration of phenol showed adverse effects on EPS release, microbial abundance and biodiversity.

•TiO2-FTCS modification was firstly applied on PVDF ENM for super-hydrophobization.•Superhydrophobic PVDF ENM was modified with a contact angle of 157.1°.•Considerable DCMD performance was exhibited on modified PVDF ENM for NaCl solution.•Modified PVDF ENM was suitable for the water recovery and desalination of RO brine.The major challenges for electrospun membranes used in direct contact membrane distillation (DCMD) process are insufficient pore wetting resistance related with hydrophobicity and pore structure of membrane surface. A novel super-hydrophobization method containing first coating TiO2 nanoparticles on membrane surface by the low temperature hydrothermal process and then the TiO2 coated membrane being fluorosilanized with low surface energy material of 1H, 1H, 2H, 2H-perfluorododecyl trichlorosilane (FTCS) was employed to modify the virgin polyvinylidene fluoride electrospun nanofiber membrane (PVDF ENM). Results showed that this TiO2-FTCS modified membrane possessed high hydrophobicity (157.1°), high mean roughness (4.63 μm), considerable wetting resistance (158 kPa), well-distributed pore size (0.81 μm), reasonable surface porosity (57%) and modest membrane thickness (55 μm). These combined properties made the modified PVDF ENM an attractive candidate for DCMD. High flux and stable desalination performances were achieved during short-term DCMD process (73.4 LMH permeate flux, 99.99% salt rejection) using 3.5 wt% NaCl solution. Long-term DCMD process with actual reverse osmosis brine as feed solution also showed high performance (40.5 LMH, 99.98%). These results exceeded those of commercial PVDF membrane and unmodified PVDF ENM significantly, suggesting the potential for PVDF ENM in DCMD applications.

A series of novel charged ultrafiltration membranes that differed in spacer arm length and charge group were generated by covalent attachment of negatively charged group to a commercially available regenerated cellulose membrane. Rejection of humic acid and flux decline were compared with essentially neutral and negatively charged versions of regenerated cellulose membranes of different spacer arm lengths and charge groups. Effects of membrane molecular weight cut-off and solution pH on humic acid removal and flux decline on neutral and negatively charged membranes of different spacer arm lengths were also compared. Results indicated that the membrane with larger spacer arm length has better rejection of humic acid and less membrane fouling compared to that with smaller spacer arm length. In addition, the modified negatively charged membrane with a strongly acidic (sulfonic acid) functional group has better rejection of humic acid and less membrane fouling than that with a weakly acidic (carboxylic acid) functional group. These experimental results are consistent with the larger charge of the membranes having larger spacer arm length and sulfonic acid group. This study confirms that the appropriate design of membrane charge functionality could be an effective way for better removal of humic acid and reduction of membrane fouling due to the electrostatic interactions with the combination effect of membrane pore size.Highlights► Different charge group modified membranes affect HA rejection and fouling differently. ► Membrane having larger spacer arm length has higher retention of HA and less fouling. ► Charge modifying effect on HA removal and fouling is larger with higher MWCO membrane. ► Effect of pH on HA rejection and fouling is larger for the membrane of larger charge.

A method which alters the substrate's physical and electrochemical properties by doping photoresist derived carbon with magnetite nanoparticles has been developed to enhance the existing substrate's ability to foster cell growth. Cyclic voltammetry, scanning electron microscopy and atomic force microscopy are used to evaluate the characters of the prepared film. And then, the magnetite nanoparticles doped carbon film is used as substrate for the growth of nerve cell. Here, rat pheochromocytoma cells are used for culture to test substrate–cell interactions. The results showed an increase in cell concentration and average neurite length with the increase of nanoparticle concentration on the surface. Importantly, the nerve cells can be grown on the magnetite nanoparticles doped carbon even in the absence of nerve growth factor. This finding will potentially provide a new material for nerve regeneration.Graphical abstractHighlights► Photo-resist derived carbon obtained using photolithographic technique was doped with magnetite nanoparticles. ► The physical property of the photoresist-derived carbon film could be easily adjusted by doping different amounts of magnetite nanoparticles. ► The nerve cells can be grown on the magnetite nanoparticles doped carbon even in the absence of nerve growth factor. ► The number of cells attached on the substrate increase with the increase of magnetite nanoparticles amounts doped in carbon.

Ultrafiltration (UF) has become one of the best alternatives replacing conventional drinking water treatment technologies because of increasing stringent regulations for drinking water quality. However, membrane fouling is an important factor which restricts its widespread application. In this study, the modified PVDF membranes were prepared by adding different amounts of PEG and TiO2 particles. The performances of PVDF–PEG membranes and PVDF–PEG–TiO2 membranes were investigated by discussing NOM removal and flux decline in both dead-end and cross-flow filtration experiments. The effect of photocatalytic degradation on TiO2-doped PVDF membranes was also evaluated. Results indicated that appropriate TiO2-doped modification on PVDF membrane could be an effective way for better removal of NOM and reduction of membrane fouling at the same time. During the ultrafiltration on TiO2-doped PVDF membrane, an equilibrium might be reached between the foulants deposited on the membrane surface and photocatalytic degradation of the foulants during cross-flow UF coupled with photocatalysis. TiO2-doped PVDF membrane also shows good self-cleaning ability. The fouled membrane can be cleaned with irradiation and the foulants’ photocatalytic degradation is most effective in the first 30 min.Highlights► Modified PVDF membrane increases NOM removal rate and decreases the flux decline. ► TiO2-doped PVDF membrane has a good self-cleaning ability. ► Fouling and photocatalytic degradation might reach equilibrium during cross-flow UF. ► Adding TiO2 to PVDF–PEG improves membrane hydrophilicity, smoothness and rejection.

•Superhydrophobic PDMS/PMMA membrane was electrospun successfully with a contact angle of 163°.•Correlations between electrospinning parameters and membrane properties were firstly established.•Membrane surface roughness and beads structure were well-related with membrane hydrophobicity.•The membrane was suitable for MD process (< 24 h) with membrane flux of 39.61 L/m2 h and salt rejection of 99.96%.Considerable efforts have been devoted to finding economic and simple preparation methods for polydimethylsiloxane (PDMS) superhydrophobic membrane in past decades. This study provides a simple method to electrospin PDMS membrane using poly (methyl methacrylate) (PMMA) as carrier polymer. Effects of PMMA concentration, PDMS/PMMA mass ratio and main parameters of electrospinning process (voltage and injection rate) were investigated to obtain superhydrophobic membrane with high water contact angle (WCA). A highest WCA of 163° could be obtained on the membrane surface fabricated by electrospinning solution containing PDMS: PMMA: tetrahydrofuran (THF): N,N-dimethylformamide (DMF) (mass ratio 1: 1: 8.88: 9.48) under applied voltage of 11 kV and injection rate of 0.1 mm/min. The superhydrophobic PDMS/PMMA membrane was further applied in membrane distillation process for desalination, and a high permeation flux of 39.61 L/m2 h and an excellent salt rejection of 99.96% were achieved during long-term MD process (24 h).

•Adding TiO2 to PVDF–LiCl improves membrane hydrophilicity, smoothness and rejection.•TiO2-doped PVDF membrane has a good self-cleaning ability.•Optimum irradiation time should be considered to offer the self-cleaning property.•UV irradiation might be a method of membrane cleaning for photocatalytic membranes.Ultrafiltration has become one of the best alternatives replacing conventional drinking water treatment technologies because of increasing stringent regulations for drinking water quality. However, membrane fouling is an important factor which restricts its widespread application. In this study, the modified polyvinylidene fluoride (PVDF) membranes were prepared by adding different amounts of LiCl and TiO2 particles. The performances of PVDF–LiCl membranes and PVDF–LiCl–TiO2 membranes were investigated by discussing the rejection of natural organic matter (NOM) and flux decline in both dead-end and cross-flow filtration experiments. The effect of photocatalytic degradation on TiO2-doped PVDF membranes was also evaluated. Results from both this study and the previous one with the membrane prepared by adding organic addition agent PEG and TiO2 photocatalyst indicated that appropriate TiO2-doped modification on PVDF membrane could be an effective way for better NOM rejection and reduction of membrane fouling at the same time. TiO2-doped PVDF membrane also shows good self-cleaning ability. The fouled membrane can be cleaned with irradiation and the foulants' photocatalytic degradation is most effective in the first 30 min.