Document Details
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Document Type |
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Thesis |
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Document Title |
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PERFORMANCE STUDY OF MEMBRANE DISTILLATION FOR SWRO BRINE TREATMENT دراسة أداء التقطير بالأغشية لمعالجة مياه رجيع محطات التحلية |
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Subject |
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Faculty of Engineering |
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Document Language |
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Arabic |
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Abstract |
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Performance of membrane distillation (MD) has been an attractive topic for water desalination scientists globally, especially after the challenges of pure water scarcity over the world. MD is a thermal process based on temperature gradient created across a microporous hydrophobic membrane, and it operates at atmospheric pressure and low temperature (below boiling temperature) comparing to other thermal desalination technology; hence, heat rejection from other plants such as condensers can effectively operate the MD. In the present investigation, an experimental study is implemented at Center of Excellence in Desalination Technology (CEDT) in King Abdul-Aziz University (KAU) which equipped with most of the required equipment to perform the lab prototype system. The overall objective of the current work is to investigate the effect of thermal treatment on the characteristics and the DCMD performance of Poly (vinylidene fluoride) (PVDF) hollow fibers membrane on seawater RO brine treatment. The PVDF hollow fibers (Made in Korea) were thermally treated at different temperatures (50oC, 70oC, 90oC, 110oC, 150oC), and used for MD modules fabrication. Then, a reference MD module was fabricated using a pristine hollow fiber membrane. The crystallinity and the allotropy of the PVDF polymer were evaluated by Differential scanning calorimetry (DSC) and Fourier-transform infrared spectroscopy (FTIR). Also, the hydrophobicity and the wettability were assessed by the contact angle, the porosity, the water uptake, and the Liquid Entry Pressure (LEP) measurements. Furthermore, the direct contact membrane distillation (DCMD) operated on seawater RO brine water, and it's parameters, feed temperature, feed flow rate, feed flow configuration (in-out and out-in), module configuration (parallel, series and package density of hollow fibers in the module) and time of operation were optimized to evaluate the performance in term of flux and salt rejection. The crystallinity investigation by DSC reveals that the used PVDF polymer has two allotropic forms (α and γ). However, ATR-FTIR investigation shows that the surface of the membrane is composed of only α-phase and the thermal treatment increased the PVDF crystallinity from 46.88 to 51.35%. Increasing hydrophobicity, porosity, pore size, and LEP from the pristine to the heated membrane (from 89.44° to 98.34°, from 51.90 to 67.28 % from 0.12 to 0.153 μm, and from 2.35 to 2.84 bar respectively) has been seen. Water uptake has been decreased (from 44.1 to 31.70 %). The highest values were obtained for 110oC. The in-out configuration shows higher LEP than the out-in. On the other hand, the thermal treatment improves the DCMD performance, and it is more sensitive for the out-in configuration. The parallel arrangement of MD modules presents higher permeate water flux than the series arrangement, and it was observed that doubling the package density of membranes in the module leads to a decrease in the water flux. At 70oC temperature feed the flux increases from 11.71 to 14.48 Kg/m2.hr for out-in configuration between raw and treated membrane with 23.6% rise in flux, however, the maximum increases percentage showed for 45oC temperature feed from 2.58 to 3.45 Kg/m2.hr with 33.7% rise in flux. |
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Supervisor |
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Prof. Dr. Salah Al Tahar Bouguecha |
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Thesis Type |
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Doctorate Thesis |
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Publishing Year |
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1442 AH
2021 AD |
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Added Date |
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Monday, September 6, 2021 |
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Researchers
| غسان جميل صفطه | Softah, Ghassan | Researcher | Doctorate | |
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