Optimizing stretching conditions in fabrication of PTFE hollow fiber membrane for performance improvement in membrane distillation

Li, Kuiling; Zhang, Yong; Xu, Lili; Zeng, Fanfu; Hou, Deyin; Wang, Jun

doi:10.1016/j.memsci.2017.12.070

Cited by 54 publications

(25 citation statements)

References 33 publications

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“…It can be said that although both compared membranes presented almost similar hydrophobicity, the higher operational stability of the PEI-Zonyl membrane can possibly be attributed to the improved asymmetric structure with smaller pores and improved wetting resistance. It is worth mentioning that the porous PTFE membranes are usually fabricated by thermal and stretching methods (Feng et al 2018;Li et al 2018), which demonstrate symmetric structure with larger pore sizes compared to the asymmetric porous membranes fabricated by non-solvent induced phase separation (NIPS) method.…”

Section: Agmd Of the Mb Solution And Fouling Studymentioning

confidence: 99%

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Mousavi

Aboosadi

Mansourizadeh

et al. 2021

Water Science and Technology

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Wetting and fouling have significantly affected the application of membrane distillation (MD). In this work, a dip-coating method was used for improving surface hydrophobicity of the polyetherimide (PEI) hollow fiber membrane. An air gap membrane distillation (AGMD) process was applied for treatment of the methylene blue (MB) solution. The porous PEI membrane was fabricated by a dry-wet spinning process and the hydrophobic 2-(Perfluoroalkyl) ethanol (Zonyl® BA) was used as the coating material. From FESEM, the modified PEI-Zonyl membrane showed an open structure with large finger-like cavities. The modified membrane displayed a narrow pore size distribution with mean pore size of 0.028 μm. The outer surface contact angle of the PEI-Zonly membrane increased from 81.3° to 100.4° due to the formation of an ultra-thin coated layer. The pure water flux of the PEI-Zonyl membrane was slightly reduced compared to the pristine PEI membrane. The permeate flux of 6.5 kg/m2 h and MB rejection of 98% was found for the PEI-Zonyl membrane during 76 h of the AGMD operation. Adsorption of MB on the membrane surface was confirmed based on the Langmuir isotherm evaluation, AFM and FESM analysis. The modified PEI-Zonyl membrane can be a favorable alternative for AGMD of dyeing wastewaters.

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Section: Agmd Of the Mb Solution And Fouling Studymentioning

confidence: 99%

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Mousavi

Aboosadi

Mansourizadeh

et al. 2021

Water Science and Technology

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“…Many membrane researchers reported using fluoropolymer membrane due to its hydrophobicity and its excellent processability such as polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and PVDF copolymer which are more hydrophobic and present higher solubility including polyvinylidene fluoride-co-hexafluoropropylene (PVDF-co-HFP), PTFE-co-hexafluoropropylene(FEP) and PVDF-co-trifluorochloroethylene (PVDF-CTFE) in order to prevent membrane wetting. 12,[16][17][18][19] Surface wettability of water contact angle for PVDF-co-HFP was 98.00°, higher compared to PVDF which was 92.19° due to addition of an amorphous phase of hexafluoropropylene (HFP) into the main constituent vinylidene fluoride (VDF) blocks as reported by Balis et al 20 Researchers have proposed several studies to investigate the effect of additive on the properties of PVDF membrane. Zheng et al used inorganic and organic macromolecule additives such as polyethylene glycol (PEG) and dibutyl phthalate (DBP) for the preparation of PVDF-CTFE membrane and observed that the membrane was found to improve hydrophobicity, relatively small pore and exhibited symmetrical cross-section structure.…”

Section: Introductionmentioning

confidence: 94%

Effect of Additives on Hydrophobicity of PVDF Membrane in Two-stage Coagulation Baths for Desalination

Ahmad¹,

Ramli²,

Esham³

2019

JPS

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This research aimed to improve the hydrophobic polyvinylidene fluoride (PVDF) membrane for direct contact membrane distillation (DCMD) desalination by mixing various additives (dibutyl phthalate and glycerol) in polymer solution via twostage/dual coagulation bath (CB) system. The effect of each additive on the surface and cross-sectional morphology of PVDF membrane was investigated. The addition of additives showed increased in membranes porosity, but the water contact angle was less than 90° when immersed in single CB (distilled water). Membrane prepared with two-stage CB system immersed into methanol CB for 20 min and transferred into distilled water CB for 24 h exhibited high water contact angle of 114.2°, 142.6° and 120.1° for membrane M-3, M-4 and M-5, respectively. The porosity of membrane significantly increased when incorporated with additives. The membrane was further evaluated in DCMD operation for separation performance. The DCMD tested using distilled water and 35 g l-1 of sodium chloride (NaCl) aqueous solution in feed showed M-4 achieved the highest flux among other membranes at 13.85 kg-2 m-2 h-1 with 99% salt rejection under 70°C of feed temperature.

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“…Instead, these materials undergo complex stretching and annealing processes in order to induce porosity. Despite this, their low surface energies and high thermal and chemical stabilities make these two materials very attractive for MD applications [107].…”

Section: Electrospinningmentioning

confidence: 99%

The use of carbon nanomaterials in membrane distillation membranes: a review

Leaper

Abdel‐Karim

Gorgojo

2021

Front. Chem. Sci. Eng.

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Membrane distillation (MD) is a thermal-based separation technique with the potential to treat a wide range of water types for various applications and industries. Certain challenges remain however, which prevent it from becoming commercially widespread including moderate permeate flux, decline in separation performance over time due to pore wetting and high thermal energy requirements. Nevertheless, its attractive characteristics such as high rejection (ca. 100%) of nonvolatile species, its ability to treat highly saline solutions under low operating pressures (typically atmospheric) as well as its ability to operate at low temperatures, enabling waste-heat integration, continue to drive research interests globally. Of particular interest is the class of carbon-based nanomaterials which includes graphene and carbon nanotubes, whose wide range of properties have been exploited in an attempt to overcome the technical challenges that MD faces. These low dimensional materials exhibit properties such as high specific surface area, high strength, tuneable hydrophobicity, enhanced vapour transport, high thermal and electrical conductivity and others. Their use in MD has resulted in improved membrane performance characteristics like increased permeability and reduced fouling propensity. They have also enabled novel membrane capabilities such as in-situ fouling detection and localised heat generation. In this review we provide a brief introduction to MD and describe key membrane characteristics and fabrication methods. We then give an account of the various uses of carbon nanomaterials for MD applications, focussing on polymeric membrane systems. Future research directions based on the findings are also suggested.

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Optimizing stretching conditions in fabrication of PTFE hollow fiber membrane for performance improvement in membrane distillation

Cited by 54 publications

References 33 publications

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Modification of porous polyetherimide hollow fiber membrane by dip-coating of Zonyl® BA for membrane distillation of dyeing wastewater

Effect of Additives on Hydrophobicity of PVDF Membrane in Two-stage Coagulation Baths for Desalination

The use of carbon nanomaterials in membrane distillation membranes: a review

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