Biomimetic hydrophobic membrane: A review of anti-wetting properties as a potential factor in membrane development for membrane distillation (MD)

2020 ◽  
Vol 91 ◽  
pp. 15-36 ◽  
Author(s):  
Wan Aisyah Fadilah Wae AbdulKadir ◽  
Abdul Latif Ahmad ◽  
Ooi Boon Seng ◽  
Nuur Fahanis Che Lah
Keyword(s):  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Wetting Properties ◽  
Potential Factor ◽  
Membrane Development

scholarly journals Carnauba Wax/Halloysite Nanotube with Improved Anti-Wetting and Permeability of Hydrophobic PVDF Membrane via DCMD

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 228
Author(s):  
Wan Aisyah Fadilah Wae AbdulKadir ◽  
Abdul Latif Ahmad ◽  
Ooi Boon Seng
Keyword(s):  
Vinylidene Fluoride ◽  
Metal Oxide Nanoparticles ◽  
Membrane Distillation ◽  
Attenuated Total Reflection ◽  
Hydrophobic Membrane ◽  
Water Contact ◽  
Halloysite Nanotube ◽  
Pvdf Membrane ◽  
Carnauba Wax ◽  
Wetting Properties

The hydrophobic membranes have been widely explored to meet the membrane characteristics for the membrane distillation (MD) process. Inorganic metal oxide nanoparticles have been used to improve the membrane hydrophobicity, but limited studies have used nano clay particles. This study introduces halloysite nanotube (HNT) as an alternative material to synthesis a hydrophobic poly(vinylidene fluoride) (PVDF)-HNT membrane. The PVDF membranes were fabricated using functionalized HNTs (e.g., carnauba wax and 1H,1H,2H,2H-perfluorooctyl-trichlorosilane (FOTS)). The results were determined by Fourier transform infrared-attenuated total reflection, scanning electron microscope, goniometer and porometer to determine the desired hydrophobic membrane for direct contact membrane distillation (DCMD). The addition of FOTS-HNT (fs-HNT) and carnauba wax-HNT (fw-HNT) in the PVDF membrane enhanced the water contact angle (CA) to 127° and 137°, respectively. The presence of fw-HNT in the PVDF membrane exhibited higher liquid entry pressure (LEP) (2.64 bar) compared to fs-HNT in the membrane matrix (1.44 bar). The PVDF/fw-HNT membrane (Pfw-HNT) obtained the highest flux of 7.24 L/m2h with 99.9% salt removal. A stable permeability in the Pfw-HNT membrane was obtained throughout 16 h of DCMD. The incorporation of fw-HNT in the PVDF membrane had improved the anti-wetting properties and the membrane performance with the anti-fouling effect.

Coupled Phenomena Membrane Distillation and Osmotic Distillation through a Porous Hydrophobic Membrane

1995 ◽  
Vol 30 (6) ◽  
pp. 993-1011 ◽  
Author(s):  
M. P. Godino ◽  
L. Peña ◽  
J. M. Ortiz De Zárate ◽  
J. I. Mengual
Keyword(s):  
Membrane Distillation ◽  
Hydrophobic Membrane ◽  
Osmotic Distillation

scholarly journals Exploiting the Interplay between Liquid-Liquid Demixing and Crystallization of the PVDF Membrane for Membrane Distillation

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
N. I. M. Nawi ◽  
M. R. Bilad ◽  
N. A. H. M. Nordin ◽  
M. O. Mavukkandy ◽  
Z. A. Putra ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Water Flux ◽  
High Water ◽  
Membrane Distillation ◽  
Degree Of Crystallinity ◽  
Solution Temperature ◽  
Hydrophobic Membrane ◽  
Sem Images ◽  
Cold Temperatures ◽  
Dope Solution

Membrane distillation (MD) purifies water by transporting its vapor through a hydrophobic membrane. An ideal MD membrane poses high water flux and high fouling, scaling, and wetting resistances. In this study, we develop polyvinylidene fluoride (PVDF) membranes for MD by focusing on reduction of PVDF degree of crystallinity. We explore the roles of dope solution temperature in dictating the phase separation mechanisms as well as the structure and the performance of semicrystalline PVDF membranes. DSC spectra show that higher dope solution temperature depresses crystallinity via formation of imperfect crystal. Such findings were also supported by FTIR and XRD results. The SEM images reveal formation of spherulite-like morphology in the membrane matrices for membranes prepared from high temperature dope solutions. A good balance between solid-liquid and liquid-liquid phase separations that offers low degree of crystallinity was found at a dope solution temperature of 60°C (PVDF-60), which showed the MD flux of 18 l/m2 h (vs. 6 l/m2 h for temperature of 25°C, as a benchmark) and nearly complete salt rejection when run at hot and cold temperatures of 65°C and 25°C, respectively. The PVDF-60 shows a high wetting resistance and stable MD flux of 10.5 l/m2 h over a 50 h test for treating brine solution as the feed (70 g NaCl/l).

Morphological Study of Fabricated PVDF Based Hydrophobic Membrane for Different Additives and Coagulation Bath Temperature

2021 ◽  
Vol 18 (3) ◽  
pp. 39-47
Author(s):  
Meenakshi Yadav ◽  
Sushant Upadhyaya ◽  
Kailash Singh ◽  
Manish Vashishtha
Keyword(s):  
Contact Angle ◽  
Water Content ◽  
Temperature Difference ◽  
Synergistic Effects ◽  
Weight Percent ◽  
Membrane Distillation ◽  
Coagulation Bath ◽  
Hydrophobic Membrane ◽  
Sem Micrograph ◽  
Dope Solution

The demand of membrane distillation (MD) has increased since last few decades for numerous applications. The membrane used in MD is hydrophobic; therefore, the focus has been emphasised on the development of a suitable membrane with desired microstructure. In this study, the flat sheet hydrophobic membrane of suitable properties has been casted with various additives such as water, ethane-di-ol, and propan-2-ol in dope solution using a non-solvent induced phase separation (NIPS) technique. The effect of water content in dope solution has been studied on casted membrane porosity and contact angle. The maximum contact angle and porosity were found to be 96° and 53.23% at 4 weight percent of water content in dope solution of PVDF polymer and di.methyl.acetamide as solvent. It was found that SEM micrograph when ethane-di-ol and propan-2-ol are used as an additive shows more finger-like pores and nodules, respectively, in the microstructure of the casted membrane. Furthermore, synergistic effects using water with other additives were also identified using SEM micrograph of casted membrane and it was observed that water with ethane-di-ol and propan-2-ol form contact angle of 98° and 105°, respectively, for 2 weight percent each additive in dope. In this study, the membrane was also cast by dissolving PVDF powder in di.methyl.acetamide solvent with lithium chloride and the effect of the temperature difference between coagulation bath and film temperature was investigated using an SEM micrograph. Overall, it was found that water content and temperature difference aid in developing hydrophobic porous membrane of desired properties for MD applications.

scholarly journals Analysis and optimization of a new cylindrical air gap membrane distillation system

2019 ◽  
Vol 20 (1) ◽  
pp. 361-371 ◽  
Author(s):  
Vandita T. Shahu ◽  
S. B. Thombre
Keyword(s):  
Flow Rate ◽  
Membrane Separation ◽  
Negative Impact ◽  
Membrane Distillation ◽  
Air Gap ◽  
Cylindrical Shape ◽  
Hydrophobic Membrane ◽  
Tube Heat Exchanger ◽  
Whole Process ◽  
Air Gap Membrane Distillation

Abstract Membrane distillation is a rate-governed non-isothermal membrane separation technique that utilizes trans-membrane temperature difference for evaporating water and thereby separating it from brackish feed for reproducing fresh water. A novel design of a cylindrical air gap membrane distillation module is presented. The module is fabricated in a way similar to a shell and tube heat exchanger. A PTFE hydrophobic membrane is used and is formed in a cylindrical shape. Design of experiments (DOE) is used to design the experiments statistically and to identify the significant operating parameters. Experiments were performed according to the Taguchi design approach using an L16 orthogonal array. Optimization of the whole process is performed by response surface methodology. It is shown that the feed temperature and feed flow rate have a positive effect, whereas the salinity has a negative impact on flux. The maximum value of flux achieved with this system is 3.6 kg/m2 hr. A high value of flux of 2.6 kg/m2 hr was achieved under optimum conditions at a temperature of 45 °C and a flow rate of 1.5 lpm with a salinity of 5 g/litre.

Development of Nano-Carbon Bucky-Paper Membranes for Membrane Distillation

2012 ◽  
Vol 724 ◽  
pp. 408-411 ◽  
Author(s):  
Jae Wuk Koo ◽  
Ji Hee Han ◽  
Sang Ho Lee ◽  
Jin Sik Sohn ◽  
June Seok Choi
Keyword(s):  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Practical Implementation ◽  
Vapor Permeability ◽  
Feed Water ◽  
Hydrophobic Membrane ◽  
Salt Rejection ◽  
Multi Stage ◽  
And Performance ◽  
Bucky Paper

Membrane distillation (MD) is a special evaporation process to produce fresh water from seawater or contaminated water using membranes. MD has advantages over other evaporation technologies such as multi-stage flash vaporization (MSF) and multi-effect distillation (MED) due to its relatively low energy requirements, allowing the use of solar energy as its heat source. Nevertheless, lack of membrane materials for MD process hinders its practical implementation for desalination and water treatment. In this study, membranes made of carbon nanotube (CNT) are presented for MD. Flat sheet hydrophobic membranes made of polyvinylidene fluoride (PVDF) were selected as supports for bucky-paper membranes, allowing formation of CNT bucky-paper without chemical reactions. Laboratory-scale systems were used to evaluate their potential and performance in direct contact MD. Water permeability and salt rejection were analyzed for each case. D.I water and synthetic feed water were used for the lab-scale tests. It was demonstrated that the physical immobilization of CNT on a hydrophobic membrane changed led to an increase in vapor permeability while improving salt rejection.

scholarly journals Performances of air gap and water gap MD desalination modules

2018 ◽  
Vol 13 (1) ◽  
pp. 200-209 ◽  
Author(s):  
Atia E. Khalifa
Keyword(s):  
Specific Energy Consumption ◽  
Membrane Distillation ◽  
Air Gap ◽  
Dominant Factor ◽  
Feed Water ◽  
Permeate Flux ◽  
Hydrophobic Membrane ◽  
Air Gap Membrane Distillation ◽  
Gap Width ◽  
Feed Temperature

Abstract Membrane distillation (MD) is a promising thermally-driven membrane separation technology for water desalination. In MD, water vapor is being separated from the hot feed water solution using a micro-porous hydrophobic membrane, due to the difference in vapor pressures across the membrane. In the present work, experiments are conducted to compare the performance of water gap membrane distillation (WGMD) and air gap membrane distillation (AGMD) modules under the main operating and design conditions including the feed and coolant temperatures, membrane material and pore sizes, and the gap width. Results showed that the WGMD module produced higher fluxes as compared to the AGMD module, for all test conditions. The feed temperature is the dominant factor affecting the system flux. The permeate flux increases with reducing the gap width for both water and air gap modules. However, WGMD module was found to be less sensitive to the change in the gap width compared to the AGMD module. The PTFE membrane produced higher permeate flux as compared to the PVDF membrane. Bigger mean pore diameter enhanced the permeate flux, however, this enhancement is marginal at high feed temperatures. With increasing the feed temperature, the GOR values increase and the specific energy consumption decreases.

Separation of Water and Nitric Acid with Porous Hydrophobic Membrane by Air Gap Membrane Distillation (AGMD)

2006 ◽  
Vol 41 (14) ◽  
pp. 3187-3199 ◽  
Author(s):  
Ramesh Thiruvenkatachari ◽  
Matheswaran Manickam ◽  
Tae Ouk Kwon ◽  
Il Shik Moon ◽  
Jae Woo Kim
Keyword(s):  
Nitric Acid ◽  
Membrane Distillation ◽  
Air Gap ◽  
Hydrophobic Membrane ◽  
Air Gap Membrane Distillation
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