A polyvinylidene fluoride (PVDF)–silica aerogel (SiAG) insulating membrane for improvement of thermal efficiency during membrane distillation

2020 ◽  
Vol 597 ◽  
pp. 117632
Author(s):  
Kuiling Li ◽  
Kunpeng Wang ◽  
Yong Zhang ◽  
Hongxin Liu ◽  
Jun Wang
Keyword(s):  
Thermal Efficiency ◽  
Silica Aerogel ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation

scholarly journals Electrospun Nanostructured Membrane Engineering Using Reverse Osmosis Recycled Modules: Membrane Distillation Application

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1601
Author(s):  
Jorge Contreras-Martínez ◽  
Carmen García-Payo ◽  
Mohamed Khayet
Keyword(s):  
Reverse Osmosis ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Permeate Flux ◽  
Electrospinning Technique ◽  
Salt Rejection ◽  
Rejection Factor ◽  
Nanofibrous Membranes ◽  
Membrane Engineering ◽  
Desalination Plants

As a consequence of the increase in reverse osmosis (RO) desalination plants, the number of discarded RO modules for 2020 was estimated to be 14.8 million annually. Currently, these discarded modules are disposed of in nearby landfills generating high volumes of waste. In order to extend their useful life, in this research study, we propose recycling and reusing the internal components of the discarded RO modules, membranes and spacers, in membrane engineering for membrane distillation (MD) technology. After passive cleaning with a sodium hypochlorite aqueous solution, these recycled components were reused as support for polyvinylidene fluoride nanofibrous membranes prepared by electrospinning technique. The prepared membranes were characterized by different techniques and, finally, tested in desalination of high saline solutions (brines) by direct contact membrane distillation (DCMD). The effect of the electrospinning time, which is the same as the thickness of the nanofibrous layer, was studied in order to optimize the permeate flux together with the salt rejection factor and to obtain robust membranes with stable DCMD desalination performance. When the recycled RO membrane or the permeate spacer were used as supports with 60 min electrospinning time, good permeate fluxes were achieved, 43.2 and 18.1 kg m−2 h−1, respectively; with very high salt rejection factors, greater than 99.99%. These results are reasonably competitive compared to other supported and unsupported MD nanofibrous membranes. In contrast, when using the feed spacer as support, inhomogeneous structures were observed on the electrospun nanofibrous layer due to the special characteristics of this spacer resulting in low salt rejection factors and mechanical properties of the electrospun nanofibrous membrane.

Potential of membrane distillation in seawater desalination: Thermal efficiency, sensitivity study and cost estimation

2008 ◽  
Vol 323 (1) ◽  
pp. 85-98 ◽  
Author(s):  
S ALOBAIDANI ◽  
E CURCIO ◽  
F MACEDONIO ◽  
G DIPROFIO ◽  
H ALHINAI ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Cost Estimation ◽  
Sensitivity Study ◽  
Membrane Distillation ◽  
Seawater Desalination

Production of calcium nitrate crystals via membrane distillation crystallization using polyvinylidene fluoride/sorbitan trioleate membranes

2021 ◽  
Vol 32 (5) ◽  
pp. 1463-1471
Author(s):  
Mohammad Nasiraee ◽  
Seyed Mahmoud Mousavi ◽  
Ehsan Saljoughi ◽  
Shirin Kiani ◽  
Kourosh Razmgar
Keyword(s):  
Polyvinylidene Fluoride ◽  
Calcium Nitrate ◽  
Membrane 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).

Superhydrophobic dual layer functionalized titanium dioxide/polyvinylidene fluoride- co -hexafluoropropylene (TiO 2 /PH) nanofibrous membrane for high flux membrane distillation

2017 ◽  
Vol 537 ◽  
pp. 140-150 ◽  
Author(s):  
Seyed Mahdi Seyed Shahabadi ◽  
Hesamoddin Rabiee ◽  
Seyed Mojtaba Seyedi ◽  
Amir Mokhtare ◽  
Jonathan A. Brant
Keyword(s):  
Titanium Dioxide ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Nanofibrous Membrane ◽  
High Flux

scholarly journals A Comparison Study of Brine Desalination using Direct Contact and Air Gap Membrane Distillation

2019 ◽  
Vol 25 (11) ◽  
pp. 47-54
Author(s):  
Ahmed Shamil Khalaf ◽  
Asrar Abdullah Hassan
Keyword(s):  
Flow Rate ◽  
Direct Contact ◽  
Polyvinylidene Fluoride ◽  
Membrane Distillation ◽  
Air Gap ◽  
Feed Flow Rate ◽  
Permeate Flux ◽  
Air Gap Membrane Distillation ◽  
Flat Sheet ◽  
Feed Temperature

Membrane distillation (MD) is a hopeful desalination technique for brine (salty) water. In this research, Direct Contact Membrane Distillation (DCMD) and  Air Gap Membrane Distillation (AGMD) will be used. The sample used is from Shat Al –Arab water (TDS=2430 mg/l). A polyvinylidene fluoride (PVDF) flat sheet membrane was used as a flat sheet form with a plate and frame cell. Several parameters were studied, such as; operation time, feed temperature, permeate temperature, feed flow rate. The results showed that with time, the flux decreases because of the accumulated fouling and scaling on the membrane surface. Feed temperature and feed flow rate had a positive effect on the permeate flux, while permeate temperature had a reverse effect on permeate flux. It is noticeable that the flux in DCMD is greater than AGMD, at the same conditions. The flux in DCMD is 10.95LMH, and that in AGMD is 7.14 LMH.  In AGMD, the air gap layer made a high resistance. Here the temperature transport reduces in the permeate side of AGMD due to the air gap resistance. The heat needed for AGMD is lower than DCMD, this leads to low permeate flux because the temperature difference between the two sides is very small, so the driving force (vapor pressure) is low.                                                                                               

scholarly journals Refinery processed water treatment via the low energy Direct Contact Membrane Distillation (DCMD)

2019 ◽  
Vol 74 ◽  
pp. 3 ◽  
Author(s):  
Khadije El Kadi ◽  
Isam Janajreh ◽  
Raed Hashaikeh ◽  
Rizwan Ahmed
Keyword(s):  
Water Treatment ◽  
Pore Size ◽  
Mass Flux ◽  
Thermal Efficiency ◽  
Membrane Distillation ◽  
Low Energy ◽  
Water Separation ◽  
Oil Water Separation ◽  
Oil Water ◽  
Oil Fouling

The amount of refinery water discharged to the environment from oil industry has increased vigorously in current times. Recent research has been focusing on the use of membrane technology for the refinery processed water treatment. Membrane Distillation (MD) is an emerging technology that has been highly marked by its low-energy requirement and high desalination efficiency. However, conventional MD membranes (i.e. PVDF) are not feasible for oil-water separation processes. That is due to the oleo-philic property of the membrane and thus, causes membrane fouling and halts the production of mass flux. An anti-oil-fouling membrane is essential for a successful oil-water separation by MD. Underwater-oleophobic as well as omniphobic are two different approaches in fabricating such membranes. The former approach is based on the asymmetric surface wettability, whereas the latter is attributed to the surface structure that is characterized by having a very large contact angle for all liquids. However, such composite membranes are characterized by their lower porosity, smaller pore size, but with unique surface slippage, in comparable with the conventional PVDF membranes. As such, in this work, high fidelity numerical simulation of DCMD is performed using non-isothermal Computational Fluid Dynamics (CFD) validated model in order to assess the role of the anti-oil-fouling membrane properties on the performance of the DCMD. Results are presented in terms of temperature polarization coefficient, mass flux, latent heat flux, and thermal efficiency. Results show the compromising effect of membrane porosity to 45% reduces the mass flux and thermal efficiency respectively by 68% and 40%, and reduction of pore size to the half (i.e. 50 nm) can cause a reduction by 50.6% in mass flux and 24.18% in thermal efficiency compared to the baseline (i.e. 100 nm). On the other hand, the omniphobic slippage effect leads to a noticeable gain of 16% in DCMD mass flux with slight gain in thermal efficiency. This can maximize mass flux and thermal efficiency to be as much as 50.3 kg/m2 h and 69%, respectively.

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