Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination

Reverse osmosis (RO) is an emerging desalination technology that holds great potential to provide an effective approach for solving global water scarcity issues. In the blooming oil and gas industries, produced water (PW) desalination is a viable option to resolve the oily water disposal issue. Howe...

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Main Author:	Ahmad, Nor Akalili
Format:	Thesis
Language:	English
Published:	2021
Subjects:	Q Science (General)
Online Access:	http://eprints.utm.my/id/eprint/102295/1/NorAkaliliAhmadPSKA2021.pdf
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spelling	my-utm-ep.1022952023-08-17T00:37:07Z Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination 2021 Ahmad, Nor Akalili Q Science (General) TA Engineering (General). Civil engineering (General) Reverse osmosis (RO) is an emerging desalination technology that holds great potential to provide an effective approach for solving global water scarcity issues. In the blooming oil and gas industries, produced water (PW) desalination is a viable option to resolve the oily water disposal issue. However, one great challenge of PW desalination is the membrane fouling caused by the presence of hydrocarbon contents in the PW. In this study, thin film nanocomposite (TFN) membrane for RO desalination was fabricated by depositing positively charged titania nanosheet (pTNS) and negatively charged titania nanosheet (nTNS) on the surface of polyamide (PA) layer via layer by layer (LbL) assembly. The pTNS was synthesized through solidstate calcination and acid ion-exchange. Through the additional step of exfoliation, single nTNS with improved hydrophilicity property was obtained. The formation of pTNS/nTNS assembly that created as TNS was formed atop PA layer with the number of bilayer ranged from 0 to 4. The hydration layer created on the surface of TNS-PA could hinder direct contact of foulants with the membrane surface, hence significantly enhanced the water permeability and salt rejection as well as foulant resistance. The characterization findings revealed that the membrane surface hydrophilicity was improved while surface roughness was decreased by increasing number of bilayer. However, the excessive TNS bilayer coating has imposed additional hydraulic resistance, resulting in the reduction of water permeability. The highest water permeability of 0.97 L·m-2·h-1·bar-1 (33% improvement) was achieved with the 2- bilayer of TNS-PA TFN membrane compared to the pristine PA membrane. The sodium chloride (NaCl) rejection was >98% which was also higher than pristine thin film composite (TFC) membrane of 96%. Furthermore, the 2-bilayer of TNS-PA TFN membrane achieved >99% for oil rejection. On the other hand, manipulating nanomaterials loading (0-0.10 wt.%) of 2-bilayer could lead to more positive features on the resultant TFN membrane. The effect of 0.05 wt.% TNS loading in tandem with controlled 2 bilayer achieved the highest permeability and solute rejection, recording 0.98 L·m-2·h-1·bar-1 and >98%, respectively. This study also found that the 2TNS-PA TFN membrane outperformed the pristine TFC membrane by exhibiting higher permeability and much lower fouling propensity for low to high concentration of saline oily water (2000 ppm, 5000 ppm and 10,000 ppm) and oily saline water (1000 ppm, 5000 ppm and 10,000 ppm) over a 960 min operation. With saline oily feedwater, the permeability relative rate became low with 84.48%, 78.82% and 78.82%, respectively. However, for oily saline feedwater, the 2TNS-PA TFN membrane achieved almost 100% flux recovery for three cycles by hydraulic washing. While the average permeability of uncoated TFC membrane could only be recovered by 95.7%, 89.1% and 82.9% for 1000 ppm, 5000 ppm and 10,000 ppm of the oily saline feedwater, respectively. The 2TNS-PA TFN membrane suffered a less significant decline and exhibited a relatively higher average permeability recovery rate compared to the TFC membrane due to the better resistance to the oil adsorption on the skin layer. Overall, the surface modification of TNS on the TFC membrane can provide hydrophilic, stable and effective thin water layer to tackle the fouling problem encountered by the TFC membrane. 2021 Thesis http://eprints.utm.my/id/eprint/102295/ http://eprints.utm.my/id/eprint/102295/1/NorAkaliliAhmadPSKA2021.pdf application/pdf en public http://dms.library.utm.my:8080/vital/access/manager/Repository/vital:149077 phd doctoral Universiti Teknologi Malaysia, Faculty of Engineering - School of Civil Engineering Faculty of Engineering - School of Civil Engineering
institution	Universiti Teknologi Malaysia
collection	UTM Institutional Repository
language	English
topic	Q Science (General) Q Science (General)
spellingShingle	Q Science (General) Q Science (General) Ahmad, Nor Akalili Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
description	Reverse osmosis (RO) is an emerging desalination technology that holds great potential to provide an effective approach for solving global water scarcity issues. In the blooming oil and gas industries, produced water (PW) desalination is a viable option to resolve the oily water disposal issue. However, one great challenge of PW desalination is the membrane fouling caused by the presence of hydrocarbon contents in the PW. In this study, thin film nanocomposite (TFN) membrane for RO desalination was fabricated by depositing positively charged titania nanosheet (pTNS) and negatively charged titania nanosheet (nTNS) on the surface of polyamide (PA) layer via layer by layer (LbL) assembly. The pTNS was synthesized through solidstate calcination and acid ion-exchange. Through the additional step of exfoliation, single nTNS with improved hydrophilicity property was obtained. The formation of pTNS/nTNS assembly that created as TNS was formed atop PA layer with the number of bilayer ranged from 0 to 4. The hydration layer created on the surface of TNS-PA could hinder direct contact of foulants with the membrane surface, hence significantly enhanced the water permeability and salt rejection as well as foulant resistance. The characterization findings revealed that the membrane surface hydrophilicity was improved while surface roughness was decreased by increasing number of bilayer. However, the excessive TNS bilayer coating has imposed additional hydraulic resistance, resulting in the reduction of water permeability. The highest water permeability of 0.97 L·m-2·h-1·bar-1 (33% improvement) was achieved with the 2- bilayer of TNS-PA TFN membrane compared to the pristine PA membrane. The sodium chloride (NaCl) rejection was >98% which was also higher than pristine thin film composite (TFC) membrane of 96%. Furthermore, the 2-bilayer of TNS-PA TFN membrane achieved >99% for oil rejection. On the other hand, manipulating nanomaterials loading (0-0.10 wt.%) of 2-bilayer could lead to more positive features on the resultant TFN membrane. The effect of 0.05 wt.% TNS loading in tandem with controlled 2 bilayer achieved the highest permeability and solute rejection, recording 0.98 L·m-2·h-1·bar-1 and >98%, respectively. This study also found that the 2TNS-PA TFN membrane outperformed the pristine TFC membrane by exhibiting higher permeability and much lower fouling propensity for low to high concentration of saline oily water (2000 ppm, 5000 ppm and 10,000 ppm) and oily saline water (1000 ppm, 5000 ppm and 10,000 ppm) over a 960 min operation. With saline oily feedwater, the permeability relative rate became low with 84.48%, 78.82% and 78.82%, respectively. However, for oily saline feedwater, the 2TNS-PA TFN membrane achieved almost 100% flux recovery for three cycles by hydraulic washing. While the average permeability of uncoated TFC membrane could only be recovered by 95.7%, 89.1% and 82.9% for 1000 ppm, 5000 ppm and 10,000 ppm of the oily saline feedwater, respectively. The 2TNS-PA TFN membrane suffered a less significant decline and exhibited a relatively higher average permeability recovery rate compared to the TFC membrane due to the better resistance to the oil adsorption on the skin layer. Overall, the surface modification of TNS on the TFC membrane can provide hydrophilic, stable and effective thin water layer to tackle the fouling problem encountered by the TFC membrane.
format	Thesis
qualification_name	Doctor of Philosophy (PhD.)
qualification_level	Doctorate
author	Ahmad, Nor Akalili
author_facet	Ahmad, Nor Akalili
author_sort	Ahmad, Nor Akalili
title	Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
title_short	Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
title_full	Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
title_fullStr	Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
title_full_unstemmed	Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
title_sort	thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination
granting_institution	Universiti Teknologi Malaysia, Faculty of Engineering - School of Civil Engineering
granting_department	Faculty of Engineering - School of Civil Engineering
publishDate	2021
url	http://eprints.utm.my/id/eprint/102295/1/NorAkaliliAhmadPSKA2021.pdf
_version_	1776100889800474624

Thin film nanocomposite reverse osmosis membrane with layer by layer assembled titania nanosheets for produced water desalination

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