東華大學圖書館 |

Silicate Materials for Low-Cost Ceramic Membranes : = Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.

Record Type:	Electronic resources : Monograph/item
Title/Author:	Silicate Materials for Low-Cost Ceramic Membranes :/
Reminder of title:	Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.
remainder title:	Silikatmaterialien fur Kostengunstige Keramikmembranen :
Author:	Abdullayev, Amanmyrat.
Description:	1 online resource (108 pages)
Notes:	Source: Dissertations Abstracts International, Volume: 84-04, Section: B.
Contained By:	Dissertations Abstracts International84-04B.
Subject:	Membranes. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29417853click for full text (PQDT)
ISBN:	9798352652602

Silicate Materials for Low-Cost Ceramic Membranes : = Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.
Abdullayev, Amanmyrat.

Silicate Materials for Low-Cost Ceramic Membranes :Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.Silikatmaterialien fur Kostengunstige Keramikmembranen :Synthese, Verarbeitung und Charakterisierung. - 1 online resource (108 pages)

Source: Dissertations Abstracts International, Volume: 84-04, Section: B.

Thesis (Ph.D.)--Technische Universitaet Berlin (Germany), 2022.

Includes bibliographical references

Although water is one of the most abundant natural resources on our blue planet, only a very small part is fresh and easily accessible for direct human use. On top of that, the distribution of freshwater resources across the planet is uneven, leading to severe crises of freshwater scarcity in many parts of the world. In addition, the global freshwater consumption rate continues to rise sharply due to the rapid development of the economy and the continued growth of the population. This inevitably leads to the generation of enormous amounts of wastewater. The wastewater should be appropriately treated before being discharged into the environment or reused to protect freshwater resources. In fact, with the implementation of efficient water treatment techniques, freshwater resources can be made accessible to all. Indeed, this seems like the most obvious way to deal with water scarcity and sustainable development. In this regard, membrane technology has attained burgeoning attention because of its low energy consumption and high efficiency. Commercially membranes are usually made from organic polymers as they offer the advantages of low production costs combined with easily adjustable pore characteristics. However, ceramic membranes have received increasing attention in recent years due to their robustness, life cycle, and energy efficiency. In addition, ceramic membranes have good stability in harsh environmental conditions, such as bacterial attacks, acidic or alkaline environments and high temperatures. However, ceramic membranes are more expensive than polymeric membranes due to their costly raw materials (alumina, zirconia, titania) and higher production costs resulting from high processing temperatures. Recently, the trend in research has been to reduce the production costs of ceramic membranes by using low-cost raw materials, low processing temperatures and/or simple processing methods. However, these low-cost materials still require high-temperature sintering, i.e., >1000°C, despite the use of various sintering aids or processes such as co-sintering. Developing low-temperature or non-sintered membrane manufacturing routes is still desirable to reduce production costs and environmental impacts further.In the first part of this thesis, cement-based membrane supports from ultrafine Portland cement are studied as a low-cost alternative to traditional oxidic ceramic supports. An environmentally friendly freeze-casting fabrication route is applied for the fabrication of porous membrane supports. This fabrication route, which does not require high-temperature sintering, could decrease the cost and environmental impact of the membrane fabrication process by eliminating extra energy consumption steps during sintering. The Archimedes method, scanning electron microscopy (SEM), micro-computed tomographic (µCT), and mercury porosimetry are applied to characterize the membrane supports in respect to open porosity, pore size distribution, morphology, and connectivity. The flexural strength of the 3 mm thick membranes is in the range from 1 to 6 MPa, as obtained by the ring-on-ring tests. The obtained membrane supports exhibit open porosity in the range between 48 and 73%, depending on fabrication conditions (cooling rate and the solid content), as determined by Archimedes method enabling water flux in the range between 79 and 180 L/(h·m2) at 0.5 bar transmembrane pressure difference and 3 mm membrane thickness.In the second part, highly crystalline mullite whiskers with an average length and diameter of 2.37 ± 1.7 mm and 0.18 ± 0.11 mm, respectively, are synthesized by a fluoride-assisted method from powders of aluminium sulfate, aluminium fluoride, and fumed silica at a temperature as low as 800 °C. Then instead of commercial materials, metakaolin - a natural mineral as the main low-cost material, is used to prepare membranes. Prepared membranes are interlocked networks of mullite whiskers. Owing to their intrinsic microstructure, obtained membranes exhibit competitive properties such as up to 63% porosity, up to 20 MPa compressive strength, and up to 579 L/(h·m2) pure water flux at 1 bar.Finally, in the third part, mullite whiskers are grown from flux. The addition of AlF3 to flux not only decreases the formation temperature of mullite to as low as 700 °C and suppresses the formation of the corundum side phase, but also increases the length and aspect ratio of the whiskers. The obtained high aspect ratio mullite whiskers are added to alumina powder as reinforcement and mullite-alumina composites are prepared by the freeze casting route. The fabricated mullite-alumina monoliths present a competitive compressive strength of 25.7 MPa while having as high as 70.6% porosity, making them a potential candidate for membrane applications.

Electronic reproduction.
Ann Arbor, Mich. :
ProQuest,
2023

Mode of access: World Wide Web

ISBN: 9798352652602Subjects--Topical Terms:

1531702
Membranes.
Index Terms--Genre/Form:

542853
Electronic books.

Silicate Materials for Low-Cost Ceramic Membranes : = Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.
LDR:11578nmm a2200385K 4500 001 2363146
005 20231116093807.5
006 m o d
007 cr mn ---uuuuu
008 241011s2022 xx obm 000 0 eng d
020 $a 9798352652602
035 $a (MiAaPQ)AAI29417853
035 $a (MiAaPQ)TechBerlin_1130316571
035 $a AAI29417853
040 $a MiAaPQ $b eng $c MiAaPQ $d NTU
100 1 $a Abdullayev, Amanmyrat. $3 3703895
245 1 0 $a Silicate Materials for Low-Cost Ceramic Membranes : $b Synthesis, Processing, and Characterization = Silikatmaterialien fur Kostengunstige Keramikmembranen : Synthese, Verarbeitung und Charakterisierung.
246 3 1 $a Silikatmaterialien fur Kostengunstige Keramikmembranen : $b Synthese, Verarbeitung und Charakterisierung.
264 0 $c 2022
300 $a 1 online resource (108 pages)
336 $a text $b txt $2 rdacontent
337 $a computer $b c $2 rdamedia
338 $a online resource $b cr $2 rdacarrier
500 $a Source: Dissertations Abstracts International, Volume: 84-04, Section: B.
500 $a Advisor: Gurlo, Aleksander;Banhart, John;Nijmeijer, Arian;Vakifahmetoglu, Cekdar.
502 $a Thesis (Ph.D.)--Technische Universitaet Berlin (Germany), 2022.
504 $a Includes bibliographical references
520 $a Although water is one of the most abundant natural resources on our blue planet, only a very small part is fresh and easily accessible for direct human use. On top of that, the distribution of freshwater resources across the planet is uneven, leading to severe crises of freshwater scarcity in many parts of the world. In addition, the global freshwater consumption rate continues to rise sharply due to the rapid development of the economy and the continued growth of the population. This inevitably leads to the generation of enormous amounts of wastewater. The wastewater should be appropriately treated before being discharged into the environment or reused to protect freshwater resources. In fact, with the implementation of efficient water treatment techniques, freshwater resources can be made accessible to all. Indeed, this seems like the most obvious way to deal with water scarcity and sustainable development. In this regard, membrane technology has attained burgeoning attention because of its low energy consumption and high efficiency. Commercially membranes are usually made from organic polymers as they offer the advantages of low production costs combined with easily adjustable pore characteristics. However, ceramic membranes have received increasing attention in recent years due to their robustness, life cycle, and energy efficiency. In addition, ceramic membranes have good stability in harsh environmental conditions, such as bacterial attacks, acidic or alkaline environments and high temperatures. However, ceramic membranes are more expensive than polymeric membranes due to their costly raw materials (alumina, zirconia, titania) and higher production costs resulting from high processing temperatures. Recently, the trend in research has been to reduce the production costs of ceramic membranes by using low-cost raw materials, low processing temperatures and/or simple processing methods. However, these low-cost materials still require high-temperature sintering, i.e., >1000°C, despite the use of various sintering aids or processes such as co-sintering. Developing low-temperature or non-sintered membrane manufacturing routes is still desirable to reduce production costs and environmental impacts further.In the first part of this thesis, cement-based membrane supports from ultrafine Portland cement are studied as a low-cost alternative to traditional oxidic ceramic supports. An environmentally friendly freeze-casting fabrication route is applied for the fabrication of porous membrane supports. This fabrication route, which does not require high-temperature sintering, could decrease the cost and environmental impact of the membrane fabrication process by eliminating extra energy consumption steps during sintering. The Archimedes method, scanning electron microscopy (SEM), micro-computed tomographic (µCT), and mercury porosimetry are applied to characterize the membrane supports in respect to open porosity, pore size distribution, morphology, and connectivity. The flexural strength of the 3 mm thick membranes is in the range from 1 to 6 MPa, as obtained by the ring-on-ring tests. The obtained membrane supports exhibit open porosity in the range between 48 and 73%, depending on fabrication conditions (cooling rate and the solid content), as determined by Archimedes method enabling water flux in the range between 79 and 180 L/(h·m2) at 0.5 bar transmembrane pressure difference and 3 mm membrane thickness.In the second part, highly crystalline mullite whiskers with an average length and diameter of 2.37 ± 1.7 mm and 0.18 ± 0.11 mm, respectively, are synthesized by a fluoride-assisted method from powders of aluminium sulfate, aluminium fluoride, and fumed silica at a temperature as low as 800 °C. Then instead of commercial materials, metakaolin - a natural mineral as the main low-cost material, is used to prepare membranes. Prepared membranes are interlocked networks of mullite whiskers. Owing to their intrinsic microstructure, obtained membranes exhibit competitive properties such as up to 63% porosity, up to 20 MPa compressive strength, and up to 579 L/(h·m2) pure water flux at 1 bar.Finally, in the third part, mullite whiskers are grown from flux. The addition of AlF3 to flux not only decreases the formation temperature of mullite to as low as 700 °C and suppresses the formation of the corundum side phase, but also increases the length and aspect ratio of the whiskers. The obtained high aspect ratio mullite whiskers are added to alumina powder as reinforcement and mullite-alumina composites are prepared by the freeze casting route. The fabricated mullite-alumina monoliths present a competitive compressive strength of 25.7 MPa while having as high as 70.6% porosity, making them a potential candidate for membrane applications.
520 $a Obwohl Wasser eine der reichhaltigsten naturlichen Ressourcen auf unserem Planeten ist, ist nur ein sehr kleiner Teil davon Frischwasser und somit fur den Menschen von alltaglicher Bedeutung. Hinzu kommt, dass die Suswasserressourcen ungleichmasig uber den Planeten verteilt sind, was in vielen Teilen der Welt zu einer schweren Suswasserknappheit fuhrt. Daruber hinaus steigt der weltweite Suswasserverbrauch aufgrund der raschen Entwicklung der Wirtschaft und des anhaltenden Bevolkerungswachstums weiterhin stark an. Dies fuhrt unweigerlich zu der Entstehung enormer Abwassermengen. Zum Schutz der Suswasserressourcen sollte das Abwasser vor der Einleitung in die Umwelt oder der Wiederverwendung entsprechend aufbereitet werden. Durch den Einsatz effizienter Aufbereitungstechniken konnen die Suswasserressourcen fur alle zuganglich gemacht werden, um die Wasserknappheit im Zuge einer nachhaltigen Entwicklung zu umzugehen. In diesem Zusammenhang hat die Membrantechnologie aufgrund ihres geringen Energieverbrauchs und ihrer hohen Effizienz zunehmend an Bedeutung gewonnen. Kommerziell werden Membranen in der Regel aus organischen Polymeren hergestellt, da sie die Vorteile niedriger Produktionskosten in Verbindung mit leicht einstellbaren Poreneigenschaften bieten. In den letzten Jahren haben jedoch keramische Membranen aufgrund ihrer Robustheit, ihrer Lebensdauer und ihrer Energieeffizienz zunehmende Beachtung erfahren. Daruber hinaus weisen Keramikmembranen eine gute Stabilitat gegenuber extremen Bedingungen auf, z. B. bakterielle Angriffe, saure oder alkalische Umgebungen und hohe Temperaturen. Allerdings sind keramische Membranen aufgrund ihrer kostspieligen Rohstoffe (Aluminiumoxid, Zirkoniumdioxid, Titandioxid) und der hoheren Produktionskosten, die sich aus den hohen Verarbeitungstemperaturen ergeben, teurer als Polymermembranen. Die Forschung versucht daher die Produktionskosten von Keramikmembranen durch die Verwendung kostengunstiger Rohstoffe, niedriger Verarbeitungstemperaturen und/oder einfacher Verarbeitungsmethoden zu senken. Diese kostengunstigen Materialien erfordern jedoch trotz der Verwendung verschiedener Sinterhilfsmittel oder Verfahren wie dem Co-Sintern immer noch eine Sinterung bei hohen Temperaturen, d. h. bei >1000 °C. Die Entwicklung von Verfahren zur Herstellung von Membranen bei niedrigen Temperaturen oder ohne Sinterung ist nach wie vor wunschenswert, um die Produktionskosten und Umweltauswirkungen weiter zu senken.Im ersten Teil dieser Arbeit werden zementbasierte Membrantrager aus ultrafeinem Portlandzement als kostengunstige Alternative zu herkommlichen oxidischen Keramiktragern untersucht. Fur die Herstellung der porosen Membrantrager wird ein umweltfreundliches Gefriergussverfahren, das sog. freeze-casting, angewandt. Diese Herstellungsmethode, die kein Hochtemperatursintern erfordert, konnte die Kosten und die Umweltauswirkungen des Membranherstellungsprozesses verringern, da die zusatzlichen Energieverbrauchsschritte wahrend des Sinterns entfallen. Die Archimedes-Methode, Rasterelektronenmikroskopie (REM), MikroComputertomographie (µCT) und Quecksilberporosimetrie werden zur Charakterisierung der Membrantrager hinsichtlich offener Porositat, Porengrosenverteilung, Morphologie und Konnektivitat eingesetzt. Die Doppelring-Biegefestigkeit der 3 mm dicken Membranen liegt in einem Bereich von 1 bis 6 MPa. Die erhaltenen Membrantrager weisen abhangig von den Herstellungsbedingungen (Abkuhlungsrate und Feststoffgehalt) eine offene Porositat zwischen 48 und 73 % auf, die einen Wasserfluss zwischen 79 und 180 L/(h m2) bei 0,5 bar transmembraner Druckdifferenz ermoglicht.Im zweiten Teil werden hochkristalline Mullitwhisker mit einer durchschnittlichen Lange von 2,37 ± 1,7 mm und einem Durchmesser von 0,18 ± 0,11 mm durch ein fluoridgestutztes Verfahren aus Aluminiumsulfat, Aluminiumfluorid und pyrogener Kieselsaure bei einer Temperatur von nur 800 °C synthetisiert. Anstelle von handelsublichen Materialien wird naturliches Metakaolin als kostengunstiges Hauptmaterial fur die Herstellung der Membranen verwendet. Die hergestellten Membranen bestehen aus ineinandergreifenden Netzwerken von Mullitwhiskern. Aufgrund dieser intrinsischen Mikrostruktur weisen die Membranen wettbewerbsfahige Eigenschaften auf, z. B. eine Porositat von bis zu 63 %, eine Druckfestigkeit von bis zu 20 MPa und einen Wasserdurchfluss von bis zu 579 L/(h m2) bei 1 bar.Im dritten Teil schlieslich werden MullitWhisker aus Flussmitteln hergestellt. Der Zusatz von AlF3 zum Flussmittel senkt nicht nur die Bildungstemperatur von Mullit auf bis zu 700 °C und unterdruckt die Bildung der Korund-Nebenphase, sondern erhoht auch die Lange und das Langen-Breiten-Verhaltnis der Whisker. Die so erhaltenen Mullitwhisker werden dem Aluminiumoxidpulver als Verstarkung hinzugefugt und die Mullit-Aluminiumoxid-Verbundwerkstoffe werden im Gefriergussverfahren hergestellt. Diese Mullit-Aluminiumoxid-Monolithen weisen eine konkurrenzfahige Druckfestigkeit von 25,7 MPa auf und haben eine Porositat von 70,6 %, was sie zu einem vielversprechenden Kandidaten fur Membrananwendungen macht.
533 $a Electronic reproduction. $b Ann Arbor, Mich. : $c ProQuest, $d 2023
538 $a Mode of access: World Wide Web
650 4 $a Membranes. $3 1531702
650 4 $a Raw materials. $3 648907
650 4 $a Minerals. $3 542841
650 4 $a Acids. $3 922327
650 4 $a Quartz. $3 1569706
650 4 $a Additives. $3 3689237
650 4 $a Clay. $3 537738
650 4 $a Water treatment. $3 3683746
650 4 $a Sodium. $3 3562677
650 4 $a Alumina. $3 3681487
650 4 $a Earth. $3 643955
650 4 $a Decomposition. $3 3561186
650 4 $a Population growth. $3 3562887
650 4 $a Cement. $3 862625
650 4 $a Arsenic removal. $3 3689761
650 4 $a Sintering. $3 814676
650 4 $a Ceramics. $3 651796
650 4 $a Composite materials. $3 654082
650 4 $a Environmental engineering. $3 548583
650 4 $a Materials science. $3 543314
650 4 $a Mineralogy. $3 516743
655 7 $a Electronic books. $2 lcsh $3 542853
690 $a 0501
690 $a 0775
690 $a 0794
690 $a 0411
710 2 $a ProQuest Information and Learning Co. $3 783688
710 2 $a Technische Universitaet Berlin (Germany). $3 3480527
773 0 $t Dissertations Abstracts International $g 84-04B.
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=29417853 $z click for full text (PQDT)