Hydrophobisation of mesoporous γ-Al2O3 with organochlorosilanes—efficiency and structure

Castricum, H.L.; Sah, Ashima; Mittelmeijer‐Hazeleger, Marjo C.; Elshof, Johan E. ten

doi:10.1016/j.micromeso.2005.02.007

Cited by 27 publications

(21 citation statements)

References 31 publications

(40 reference statements)

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“…Organo-silane products are used in surface modification to provide a convenient and stable means to create a hydrophobic ceramic surface and tailor the effective pore size (Miller and Koros 1990;Caro et al 1998;Castricum et al 2005;Javaid et al 2001;Abidi et al 2006;Hyun et al 1996;Leger et al 1996;Randon and Paterson 1997). Alkyl, chloro-alkyl, or fluoro-alkyl silanes of varying carbon chain lengths can be used to provide chemical affinity, to improve the separation performance, and to provide a specific degree of pore size reduction (Javaid et al 2001).…”

Section: Grafting Processmentioning

confidence: 99%

Synthesis of alumina, titania, and alumina-titania hydrophobic membranes via sol?gel polymeric route

et al. 2013

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Nanometer TiO 2 -Al 2 O 3 composite membranes were synthesized through the sol-gel polymeric reaction of TiCl 4 and AlCl 3 in the presence of acrylic-acrylamide copolymer as a template. The dried samples were characterized by DTA, TGA, FTIR, XRD, and TEM to determine the thermal behavior, chemical composition, crystal structure, shape, and size of the particles. Octyltrichlorosilane was chosen as a silane coupling agent to increase the hydrophobic nature of the prepared membranes. The morphological structure, hydrophobic nature, water permeability, and desalination efficiency of the prepared membranes were studied by SEM, contact angle, permeability, and NaCl rejection coefficient (R%) measurements. The crystal structure of titania and alumina particles in the composite was affected by the AlCl 3 and TiCl 4 feed ratio. As the titania concentration increased, the average particle size of the composite particles became larger and the uniformity of the membrane layer decreased. The alumina (75%)-titania (25%) composite (AT25) showed a uniform crack-free membrane layer with a pore diameter of 12.9 nm and a porosity of 21.46%, with great hydrophobic nature, and with contact angle reaching 116°. This membrane can withstand calcination temperature up to 700°C, as the alumina and titania were present in their active forms: gamma-alumina and anatase, respectively. The membrane produced from this composite showed a high surface area of 333 m 2 /g with a respective particle size of 4.6 nm. Moreover, it showed a high ability to reject NaCl from water with a rejection coefficient of 73% and a high permeation flux of 4.8 l/h m 2 at 75°C.

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Section: Grafting Processmentioning

confidence: 99%

Synthesis of alumina, titania, and alumina-titania hydrophobic membranes via sol?gel polymeric route

et al. 2013

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“…Grafting polymers on ceramic membranes offers the opportunity to tailor and manipulate interfacial properties, while retaining the mechanical strength and geometry of the supported ceramic material. Several types of molecules can be used for modification of inorganic materials, for instance phosphate derivatives [4][5][6], chlorosilanes and alkoxysilanes [2,3,7,8], polysiloxanes [9] and Grignard reactants [10]. The strategy employed in this paper, is grafting with polydimethylsiloxanes.…”

Section: Introductionmentioning

confidence: 99%

“…Because no solvents are used in the gas or vapour phase deposition method, the presence of water can be excluded. Still modification of metal oxides with different kinds of organosilanes is mostly performed by solution phase methods [4][5][6][7][16][17][18][19][20][21][22][23]27,28]. In literature some studies are reported on gas-solid reactions of silanes onto metal oxide surfaces [22,24,25].…”

Section: Introductionmentioning

confidence: 99%

Chemical modification/grafting of mesoporous alumina with polydimethylsiloxane (PDMS)

et al. 2015

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A method for polydimethylsiloxane grafting of alumina powders is described which involves chemical modification of the surface of mesoporous (5 nm) γ-alumina flakes with a linker (3-aminopropyltriethoxysilane: APTES), either by a solution phase (SPD) or a vapour phase (VPD) reaction, followed by PDMS grafting. The systems were analysed by FTIR, gas adsorption/desorption and TGA. Grafting is proven by FTIR for all cases, meaning that a covalent bond exists between inorganic particle and organic moiety. It is demonstrated that the way of applying APTES (by SPD or VPD) has an effect on the morphology of linker as well as of PDMS. A more controlled grafting of the APTES linker on γ-alumina is possible by the VPD method, resulting in efficient grafting and good infiltration of PDMS in the pores of the inorganic system. Stability tests on these PDMS grafted alumina show no degradation after 14 days soaking in a wide range of solvents. Surface modification of metal oxide particles by organic moieties via a chemical reaction can adapt its interfacial properties and renders a high chemical stability of these inorganic-organic hybrids. This validates the use of these materials under severe applications like in membranes for solvent nanofiltration or for protein immobilization and resin modification in e.g. chromatographic applications.

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“…In earlier work on -Al 2 O 3 powders [22] we demonstrated that both monofunctional ((CH 3 ) 3 SiCl) and a difunctional ((CH 3 ) 2 SiCl 2 ) methylchlorosilanes can be effective for bulk modification of mesoporous materials with pore sizes around 4-5 nm. Steric hindrance limits the use of silanes with long organic tails to materials with much larger pore sizes.…”

Section: Introductionmentioning

confidence: 89%

Increasing the hydrothermal stability of mesoporous SiO2 with methylchlorosilanes—a ‘structural’ study

Castricum

Mittelmeijer‐Hazeleger

Sah

et al. 2006

Microporous and Mesoporous Materials

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Increasing the hydrothermal stability of mesoporous SiO2 with methylchlorosilanes -a structural study Castricum, H.L.; Mittelmeijer-Hazeleger, M.C.; Sah, A.; ten Elshof, J.E. General rightsIt is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulationsIf you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: http://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Both silanes lead to lower surface polarity and increased hydrothermal stability, i.e., preservation of the porous structure during exposure to water. As DMDCS reacts more extensively, this agent would be recommended for ceramics with pore

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Hydrophobisation of mesoporous γ-Al2O3 with organochlorosilanes—efficiency and structure

Cited by 27 publications

References 31 publications

Synthesis of alumina, titania, and alumina-titania hydrophobic membranes via sol?gel polymeric route

Synthesis of alumina, titania, and alumina-titania hydrophobic membranes via sol?gel polymeric route

Chemical modification/grafting of mesoporous alumina with polydimethylsiloxane (PDMS)

Increasing the hydrothermal stability of mesoporous SiO2 with methylchlorosilanes—a ‘structural’ study

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