Physicochemical study of polyvinylidene fluoride–Cloisite15A® composite membranes for membrane distillation application

RSC Advances ◽  
2014 ◽  
Vol 4 (108) ◽  
pp. 63367-63379 ◽  
Author(s):  
N. M. Mokhtar ◽  
W. J. Lau ◽  
A. F. Ismail ◽  
B. C. Ng
Keyword(s):  
Physicochemical Properties ◽  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Positive Impact ◽  
Composite Membranes ◽  
Membrane Distillation ◽  
Physicochemical Study ◽  
Hollow Fiber Membranes ◽  
Fiber Membranes

The effect of Cloisite15A® on the physicochemical properties of PVDF hollow fiber membranes was studied. The inclusion of Cloisite15A® in PVDF has a positive impact on the physicochemical properties of the membrane and significantly improves the DCMD performance.

scholarly journals Preparation of hydrophobic PVDF hollow fiber membranes for desalination through membrane distillation

2009 ◽  
Vol 59 (6) ◽  
pp. 1219-1226 ◽  
Author(s):  
Deyin Hou ◽  
Jun Wang ◽  
Dan Qu ◽  
Zhaokun Luan ◽  
Changwei Zhao ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Tap Water ◽  
Membrane Distillation ◽  
Water Soluble ◽  
Hollow Fiber Membranes ◽  
Water Soluble Polymer ◽  
Water Permeation ◽  
Fiber Membranes ◽  
Solvent Additive

Fabrication of polyvinylidene fluoride (PVDF) hydrophobic asymmetric hollow fiber membranes was studied by introducing inorganic salt LiCl and water soluble polymer polyethylene glycol (PEG) 1500, using N,N-dimethylacetamide (DMAc) as solvent and tap water as the coagulation medium. The membranes properties also were tested and characterized. It is found that the non-solvent additive can increase membranes porosity, ether LiCl or PEG 1500. Because of the addition of PEG 1500, the PVDF membranes obtained a rough topography on the membrane surface and the contact angle of the PVDF membranes increased to 113.50° compared to 89.82° of the PVDF membranes spun without an additive. During direct contact membrane distillation (DCMD) of 0.6 M sodium chloride solution, the PVDF membranes spun with PEG 1500 as a non-solvent additive achieved higher water permeation flux compared to the membranes spun from PVDF/DMAc and PVDF/DMAC/LiCl dopes, but the latter two membranes exhibited higher salt rejection rate.

scholarly journals Seawater Desalination by Modified Membrane Distillation: Effect of Hydrophilic Surface Modifying Macromolecules Addition into PVDF Hollow Fiber Membrane

Membranes ◽  
2021 ◽  
Vol 11 (12) ◽  
pp. 924
Author(s):  
Mochammad Purwanto ◽  
Nindita Cahya Kusuma ◽  
Ma’rup Ali Sudrajat ◽  
Juhana Jaafar ◽  
Atikah Mohd Nasir ◽  
...  
Keyword(s):  
Hollow Fiber ◽  
Polyvinylidene Fluoride ◽  
Hollow Fiber Membrane ◽  
Membrane Distillation ◽  
Hydrophilic Surface ◽  
Hollow Fiber Membranes ◽  
Permeate Flux ◽  
Seawater Desalination ◽  
Salt Rejection ◽  
Fiber Membranes

Hollow fiber membranes of polyvinylidene fluoride (PVDF) were prepared by incorporating varying concentrations of hydrophilic surface-modifying macromolecules (LSMM) and a constant amount of polyethylene glycol (PEG) additives. The membranes were fabricated by the dry-wet spinning technique. The prepared hollow fiber membranes were dip-coated by hydrophobic surface-modifying macromolecules (BSMM) as the final step fabrication. The additives combination is aimed to produce hollow fiber membranes with high flux permeation and high salt rejection in the matter of seawater desalination application. This study prepares hollow fiber membranes from the formulation of 18 wt. % of PVDF mixed with 5 wt. % of PEG and 3, 4, and 5 wt. % of LSMM. The membranes are then dip-coated with 1 wt. % of BSMM. The effect of LSMM loading on hydrophobicity, morphology, average pore size, surface porosity, and membrane performance is investigated. Coating modification on LSMM membranes showed an increase in contact angle up to 57% of pure, unmodified PVDF/PEG membranes, which made the fabricated membranes at least passable when hydrophobicity was considered as one main characteristic. Furthermore, The PVDF/PEG/4LSMM-BSMM membrane exhibits 161 °C of melting point as characterized by the DSC. This value indicates an improvement of thermal behavior shows so as the fabricated membranes are desirable for membrane distillation operation conditions range. Based on the results, it can be concluded that PVDF/PEG membranes with the use of LSMM and BSMM combination could enhance the permeate flux up to 81.32 kg·m−2·h−1 at the maximum, with stable salt rejection around 99.9%, and these are found to be potential for seawater desalination application.

Effect of Hydrophobicity Degree on PVDF Hollow Fiber Membranes for Textile Wastewater Treatment Using Direct Contact Membrane Distillation

2013 ◽  
Vol 65 (4) ◽  
Author(s):  
N. M. Mokhtar ◽  
W. J. Lau ◽  
P. S. Goh
Keyword(s):  
Contact Angle ◽  
Hollow Fiber ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Textile Wastewater ◽  
Membrane Distillation ◽  
Hollow Fiber Membranes ◽  
Hydrophobic Membrane ◽  
Direct Contact Membrane Distillation ◽  
Fiber Membranes

The objectives of this study are to study the effect of hydrophobicity degree of  polyvinylidene fluoride (PVDF) hollow fiber membranes blended with different types of additives i.e. ethylene glycol (EG) and polyvinylpyrrolidone (PVP) on textile wastewater application. The degree of hydrophobicity of each membrane was analyzed using contact angle goniometer. The membrane morphology and gas permeability were characterized prior to filtration experiment. Both membranes were tested using direct contact membrane distillation (DCMD) system and their performances were evaluated with respect to water flux and dye removal. This study revealed that the membrane with higher contact angle has greater stability in terms of flux and dye rejection compared to the membrane with low hydrophobic property. This is mainly due to the low surface energy obtained by the highly hydrophobic membrane that prevented the liquids from both sides to penetrate through membrane pores.

scholarly journals Performance Comparison between Polyvinylidene Fluoride and Polytetrafluoroethylene Hollow Fiber Membranes for Direct Contact Membrane Distillation

Membranes ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 52 ◽  
Author(s):  
Frank Y. C. Huang ◽  
Allie Arning
Keyword(s):  
United States ◽  
Hollow Fiber ◽  
Packing Density ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Water Flux ◽  
Membrane Distillation ◽  
Hollow Fiber Membranes ◽  
Direct Contact Membrane Distillation ◽  
Fiber Membranes

Increasing water demand coupled with projected climate change puts the Southwestern United States at the highest risk of water sustainability by 2050. Membrane distillation offers a unique opportunity to utilize the substantial, but largely untapped geothermal brackish groundwater for desalination to lessen the stress. Two types of hydrophobic, microporous hollow fiber membranes (HFMs), including polytetrafluoroethylene (PTFE) and polyvinylidene fluoride (PVDF), were evaluated for their effectiveness in direct contact membrane distillation (DCMD). Water flux and salt rejection were measured as a function of module packing density and length in lab-scale systems. The PVDF HFMs generally exhibited higher water flux than the PTFE HFMs possibly due to thinner membrane wall and higher porosity. As the packing density or module length increased, water flux declined. The water production rate per module, however, increased due to the larger membrane surface area. A pilot-scale DCMD system was deployed to the 2nd largest geothermally-heated greenhouse in the United States for field testing over a duration of about 22 days. The results demonstrated the robustness of the DCMD system in the face of environmental fluctuation at the facility.

scholarly journals Preparation and characterization of different geometrical shapes of multi-bore hollow fiber membranes and application in vacuum membrane distillation

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Elham M. El-Zanati ◽  
Eman Farg ◽  
Esraa Taha ◽  
Ayman El-Guindi ◽  
Heba Abdallah
Keyword(s):  
Mechanical Properties ◽  
Flow Rate ◽  
Hollow Fiber ◽  
Amorphous Structure ◽  
Membrane Distillation ◽  
Operating Conditions ◽  
Hollow Fiber Membranes ◽  
Preparation Conditions ◽  
Geometrical Shapes ◽  
Fiber Membranes

Abstract Multi-bore hollow fiber membranes were prepared through phase inversion spinning process using new locally designed spinnerets of various geometrical shapes. The spun cylindrical-like, rectangular or ribbon-like, and triangular-like are prepared, dried, and characterized by scanning electronic microscope. Fibers of circular (seven, five, and four bores) shape, rectangular of five bores, and triangular of three bores were chosen to study the effect of both geometrical configuration and the number of bores on the amorphous structure and the mechanical properties of the membranes. Membrane geometry, surface amorphous, and bore arrangements are very sensitive to the operating conditions, especially the extrusion and drawing rates. Three polymeric blends of different compositions are used to prepare multi-bore hollow fiber membranes. This study revealed that the blend composition of PES 16%, PVP 2%, PEG 2%, diethylene glycol 2%, and NMP 78% gives excellent mechanical properties. Optimization of the preparation conditions also developed, where the dope flow rate, the bore flow rate, and the air gap were 1.14 cm3 s−1, 1.1 cm3 s−1, and 0 cm, respectively. Furthermore, this study proved that the circular arrangement has high mechanical strength. The prepared seven-MBHF membranes were applied in the membrane distillation process, a solution of 35 g/l NaCl was used to test the membrane performance, and the achieved flux and rejection were 28.32 L/m2 h and 98.9%, respectively. This performance demonstrated that the prepared membrane in this way is suitable to compete with conventional reverse osmosis technology that uses single track hollow fibers.

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