1
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Kanezashi M, Hataoka N, Ikram R, Nagasawa H, Tsuru T. Hydrothermal stability of fluorine‐induced microporous silica membranes: Effect of steam treatment conditions. AIChE J 2021. [DOI: 10.1002/aic.17292] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Affiliation(s)
- Masakoto Kanezashi
- Chemical Engineering Program, Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan
| | - Naoya Hataoka
- Chemical Engineering Program, Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan
| | - Rana Ikram
- Chemical Engineering Program, Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan
| | - Hiroki Nagasawa
- Chemical Engineering Program, Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan
| | - Toshinori Tsuru
- Chemical Engineering Program, Graduate School of Advanced Science and Engineering Hiroshima University Hiroshima Japan
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2
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Tada S, Ando S, Asaka T, Daiko Y, Honda S, Bernard S, Iwamoto Y. Hydrogen transport property of polymer-derived cobalt cation-doped amorphous silica. Inorg Chem Front 2021. [DOI: 10.1039/d0qi01035a] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The effect of the local structure of Co-doped amorphous silica on the hydrogen transport property was studied with the aim to improve the high-temperature hydrogen-permselectivity of microporous amorphous silica-based membranes.
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Affiliation(s)
- Shotaro Tada
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
| | - Shiori Ando
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
| | - Toru Asaka
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
| | - Yusuke Daiko
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
| | - Sawao Honda
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
| | | | - Yuji Iwamoto
- Department of Life Science and Applied Chemistry
- Graduate School of Engineering
- Nagoya Institute of Technology
- Nagoya 466-8555
- Japan
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3
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Tada S, Saito S, Mori A, Mizuno H, Ando S, Asaka T, Daiko Y, Honda S, Bernard S, Iwamoto Y. Reversible Redox Property of Co(III) in Amorphous Co-doped SiO 2/γ-Al 2O 3 Layered Composites. MATERIALS 2020; 13:ma13235345. [PMID: 33255789 PMCID: PMC7728299 DOI: 10.3390/ma13235345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/29/2020] [Revised: 11/17/2020] [Accepted: 11/23/2020] [Indexed: 11/23/2022]
Abstract
This paper reports on a unique reversible reducing and oxidizing (redox) property of Co(III) in Co-doped amorphous SiO2/γ-Al2O3 composites. The Fenton reaction during the H2O2-catalyzed sol–gel synthesis utilized in this study lead to the partial formation of Co(III) in addition to Co(II) within the composites. High-resolution transmission electron microscopy (HRTEM) and high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) analyses for the composite powder sample with a composition of Al:Si:Co = 85:10:5 showed the amorphous state of the Co-doped SiO2 that modified γ-Al2O3 nanocrystalline surfaces. In situ X-ray absorption fine structure (XAFS) spectroscopic analysis suggested reversible redox reactions of Co species in the composite powder sample during heat-treatment under H2 at 500 °C followed by subsequent cooling to RT under Ar. Further analyses by in situ IR spectroscopy combined with cyclic temperature programmed reduction/desorption (TPR/TPD) measurements and X-ray photoelectron spectroscopic (XPS) analysis revealed that the alternating Co(III)/(II) redox reactions were associated with OH formation (hydrogenation)-deformation (dehydrogenation) of the amorphous aluminosilicate matrix formed in situ at the SiO2/γ-Al2O3 hetero interface, and the redox reactions were governed by the H2 partial pressure at 250–500 °C. As a result, a supported mesoporous γ-Al2O3/Co-doped amorphous SiO2/mesoporous γ-Al2O3 three-layered composite membrane exhibited an H2-triggered chemical valve property: mesopores under H2 flow (open) and micropores under He flow (closure) at 300–500 °C.
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Affiliation(s)
- Shotaro Tada
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Shota Saito
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Akito Mori
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Hideki Mizuno
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Shiori Ando
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Toru Asaka
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Yusuke Daiko
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Sawao Honda
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
| | - Samuel Bernard
- Centre Européen de la Céramique, University of Limoges, 12 Rue Atlantis, 87068 Limoges, France;
| | - Yuji Iwamoto
- Department of Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555, Japan; (S.T.); (S.S.); (A.M.); (H.M.); (S.A.); (T.A.); (Y.D.); (S.H.)
- Correspondence: ; Tel.: +81-52-735-5276
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4
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Development of Hybrid and Templated Silica-P123 Membranes for Brackish Water Desalination. Polymers (Basel) 2020; 12:polym12112644. [PMID: 33182780 PMCID: PMC7697223 DOI: 10.3390/polym12112644] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2020] [Revised: 10/26/2020] [Accepted: 10/26/2020] [Indexed: 11/19/2022] Open
Abstract
Water scarcity is still a pressing issue in many regions. The application of membrane technology through water desalination to convert brackish to potable water is a promising technology to solve this issue. This study compared the performance of templated TEOS-P123 and ES40-P123 hybrid membranes for brackish water desalination. The membranes were prepared by the sol–gel method by employing tetraethyl orthosilicate (TEOS) for the carbon-templated silica (soft template) and ethyl silicate (ES40) for the hybrid organo-silica. Both sols were templated by adding 35 wt.% of pluronic triblock copolymer (P123) as the carbon source. The silica-templated sols were dip-coated onto alumina support (four layers) and were calcined by using the RTP (rapid thermal processing) method. The prepared membranes were tested using pervaporation set up at room temperature (~25 °C) using brackish water (0.3 and 1 wt.%) as the feed. It was found that the hybrid membrane exhibited the highest specific surface area (6.72 m2·g−1), pore size (3.67 nm), and pore volume (0.45 cm3·g−1). The hybrid ES40-P123 was twice thicker (2 μm) than TEOS-P123-templated membranes (1 μm). Lastly, the hybrid ES40-P123 displayed highest water flux of 6.2 kg·m−2·h−1. Both membranes showed excellent robustness and salt rejections of >99%.
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Fluorine-induced microporous silica membranes: Dramatic improvement in hydrothermal stability and pore size controllability for highly permeable propylene/propane separation. J Memb Sci 2018. [DOI: 10.1016/j.memsci.2017.11.072] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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6
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Kanezashi M, Matsugasako R, Tawarayama H, Nagasawa H, Tsuru T. Pore size tuning of sol-gel-derived triethoxysilane (TRIES) membranes for gas separation. J Memb Sci 2017. [DOI: 10.1016/j.memsci.2016.11.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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7
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Darmawan A, Motuzas J, Smart S, Julbe A, Diniz da Costa JC. Gas permeation redox effect of binary iron oxide/cobalt oxide silica membranes. Sep Purif Technol 2016. [DOI: 10.1016/j.seppur.2016.07.030] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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8
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Wang S, Wang DK, Motuzas J, Smart S, Diniz da Costa JC. Rapid thermal treatment of interlayer-free ethyl silicate 40 derived membranes for desalination. J Memb Sci 2016. [DOI: 10.1016/j.memsci.2016.06.005] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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9
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Kim JE, Lim J, Lee GY, Choi SH, Maiti UN, Lee WJ, Lee HJ, Kim SO. Subnanometer Cobalt-Hydroxide-Anchored N-Doped Carbon Nanotube Forest for Bifunctional Oxygen Catalyst. ACS APPLIED MATERIALS & INTERFACES 2016; 8:1571-1577. [PMID: 26766495 DOI: 10.1021/acsami.5b10297] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Electrochemical oxygen redox reactions are the crucial elements for energy conversion and storage including fuel cells and metal air batteries. Despite tremendous research efforts, developing high-efficient, low-cost, and durable bifunctional oxygen catalysts remains a major challenge. We report a new class of hybrid material consisting of subnanometer thick amorphous cobalt hydroxide anchored on NCNT as a durable ORR/OER bifunctional catalyst. Although amorphous cobalt species-based catalysts are known as good OER catalysts, hybridizing with NCNT successfully enhanced ORR activity by promoting a 4e reduction pathway. Abundant charge carriers in amorphous cobalt hydroxide are found to trigger the superior OER activity with high current density and low Tafel slope as low as 36 mV/decade. A remarkably high OER turnover frequency (TOF) of 2.3 s(-1) at an overpotential of 300 mV was obtained, one of the highest values reported so far. Moreover, the catalytic activity was maintained over 120 h of cycling. The unique subnanometer scale morphology of amorphous hydroxide cobalt species along with intimate cobalt species-NCNT interaction minimizes the deactivation of catalyst during prolonged repeated cycles.
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Affiliation(s)
- Ji Eun Kim
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Joonwon Lim
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Gil Yong Lee
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Sun Hee Choi
- Pohang Accelerator Laboratory (PAL), Pohang University of Science and Technology (POSTECH) , Pohang 37673, Republic of Korea
| | - Uday Narayan Maiti
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Won Jun Lee
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Ho Jin Lee
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
| | - Sang Ouk Kim
- National Creative Research Initiative (CRI) Center for Multi-Dimensional Directed Nanoscale Assembly, Department of Material Science and Engineering, KAIST , Daejeon 34141, Republic of Korea
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Ji G, Smart S, Bhatia SK, Diniz da Costa JC. Improved pore connectivity by the reduction of cobalt oxide silica membranes. Sep Purif Technol 2015. [DOI: 10.1016/j.seppur.2015.09.065] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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11
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Ternary Phase-Separation Investigation of Sol-Gel Derived Silica from Ethyl Silicate 40. Sci Rep 2015; 5:14560. [PMID: 26411484 PMCID: PMC4585945 DOI: 10.1038/srep14560] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/28/2015] [Indexed: 11/12/2022] Open
Abstract
A ternary phase-separation investigation of the ethyl silicate 40 (ES40) sol-gel process was conducted using ethanol and water as the solvent and hydrolysing agent, respectively. This oligomeric silica precursor underwent various degrees of phase separation behaviour in solution during the sol-gel reactions as a function of temperature and H2O/Si ratios. The solution composition within the immiscible region of the ES40 phase-separated system shows that the hydrolysis and condensation reactions decreased with decreasing reaction temperature. A mesoporous structure was obtained at low temperature due to weak drying forces from slow solvent evaporation on one hand and formation of unreacted ES40 cages in the other, which reduced network shrinkage and produced larger pores. This was attributed to the concentration of the reactive sites around the phase-separated interface, which enhanced the condensation and crosslinking. Contrary to dense silica structures obtained from sol-gel reactions in the miscible region, higher microporosity was produced via a phase-separated sol-gel system by using high H2O/Si ratios. This tailoring process facilitated further condensation reactions and crosslinking of silica chains, which coupled with stiffening of the network, made it more resistant to compression and densification.
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12
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Ballinger B, Motuzas J, Smart S, Diniz da Costa JC. Gas permeation redox effect on binary lanthanum cobalt silica membranes with enhanced silicate formation. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.04.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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13
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Nanoscale assembly of lanthanum silica with dense and porous interfacial structures. Sci Rep 2015; 5:8210. [PMID: 25644988 PMCID: PMC4316191 DOI: 10.1038/srep08210] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2014] [Accepted: 01/13/2015] [Indexed: 11/23/2022] Open
Abstract
This work reports on the nanoscale assembly of hybrid lanthanum oxide and silica structures, which form patterns of interfacial dense and porous networks. It was found that increasing the molar ratio of lanthanum nitrate to tetraethyl orthosilicate (TEOS) in an acid catalysed sol-gel process alters the expected microporous metal oxide silica structure to a predominantly mesoporous structure above a critical lanthanum concentration. This change manifests itself by the formation of a lanthanum silicate phase, which results from the reaction of lanthanum oxide nanoparticles with the silica matrix. This process converts the microporous silica into the denser silicate phase. Above a lanthanum to silica ratio of 0.15, the combination of growth and microporous silica consumption results in the formation of nanoscale hybrid lanthanum oxides, with the inter-nano-domain spacing forming mesoporous volume. As the size of these nano-domains increases with concentration, so does the mesoporous volume. The absence of lanthanum hydroxide (La(OH)3) suggests the formation of La2O3 surrounded by lanthanum silicate.
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Liu L, Wang DK, Martens DL, Smart S, Diniz da Costa JC. Influence of sol–gel conditioning on the cobalt phase and the hydrothermal stability of cobalt oxide silica membranes. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2014.10.037] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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15
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Martens DL, Wang DK, Motuzas J, Smart S, da Costa JCD. Modulation of microporous/mesoporous structures in self-templated cobalt-silica. Sci Rep 2015; 5:7970. [PMID: 25609189 PMCID: PMC4302294 DOI: 10.1038/srep07970] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/02/2014] [Indexed: 11/08/2022] Open
Abstract
Finite control of pore size distributions is a highly desired attribute when producing porous materials. While many methodologies strive to produce such materials through one-pot strategies, oftentimes the pore structure requires post-treatment modification. In this study, modulation of pore size in cobalt-silica systems was investigated by a novel, non-destructive, self-templated method. These systems were produced from two cobalt-containing silica starting materials which differed by extent of condensation. These starting materials, sol (SG') and xerogel (XG'), were mixed with pure silica sol to produce materials containing 5-40 mol% Co. The resultant SG-series materials exhibited typical attributes for cobalt-silica systems: mesoporous characteristics developed at high cobalt concentrations, coinciding with Co3O4 formation; whereas, in the XG-series materials, these mesoporous characteristics were extensively suppressed. Based on an examination of the resultant materials a mechanism describing the pore size formation and modulation of the two systems was proposed. Pore size modulation in the XG-series was caused, in part, by the cobalt source acting as an autogenous template for the condensation of the silica network. These domains could be modified when wetted, allowing for the infiltration and subsequent condensation of silica oligomers into the pre-formed, mesoporous cages, leading to a reduction in the mesoporous content of the final product.
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Affiliation(s)
- Dana L. Martens
- The University of Queensland, FIMLab – Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, QLD 4072, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
| | - David K. Wang
- The University of Queensland, FIMLab – Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, QLD 4072, Australia
| | - Julius Motuzas
- The University of Queensland, FIMLab – Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, QLD 4072, Australia
| | - Simon Smart
- The University of Queensland, FIMLab – Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, QLD 4072, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
| | - João C. Diniz da Costa
- The University of Queensland, FIMLab – Films and Inorganic Membrane Laboratory, School of Chemical Engineering, Brisbane, QLD 4072, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
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16
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Darmawan A, Motuzas J, Smart S, Julbe A, Diniz da Costa JC. Binary iron cobalt oxide silica membrane for gas separation. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2014.09.033] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Wang S, Wang DK, Jack KS, Smart S, Diniz da Costa JC. Improved hydrothermal stability of silica materials prepared from ethyl silicate 40. RSC Adv 2015. [DOI: 10.1039/c4ra12483a] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Hydrothermally stable ES40-derived silica matrices with less than 30% pore volume loss are closely associated with a more open silica microstructure formed from thermal consolidation of larger silica particles.
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Affiliation(s)
- Shengnan Wang
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - David K. Wang
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - Kevin S. Jack
- The University of Queensland
- Centre for Microscopy and Microanalysis
- Brisbane
- Australia
| | - Simon Smart
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - João C. Diniz da Costa
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
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18
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Ballinger BJ, Motuzas J, Smart S, Diniz da Costa JC. Redox structural control of Pd and PdO silica matrices. RSC Adv 2015. [DOI: 10.1039/c5ra11085h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Pd crystallite sizes within silica were controlled by calcination in either oxidation or reduction conditions. Control was imparted by the temperature of decomposition of the PdCl2 precursor, and thus the degree of condensation of the silica matrix.
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Affiliation(s)
- Benjamin J. Ballinger
- The University of Queensland
- FIM2Lab – Functional Interfacial Materials and Membranes Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - Julius Motuzas
- The University of Queensland
- FIM2Lab – Functional Interfacial Materials and Membranes Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - Simon Smart
- The University of Queensland
- FIM2Lab – Functional Interfacial Materials and Membranes Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
| | - João C. Diniz da Costa
- The University of Queensland
- FIM2Lab – Functional Interfacial Materials and Membranes Laboratory
- School of Chemical Engineering
- Brisbane
- Australia
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19
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Ji G, Wang G, Hooman K, Bhatia S, Diniz da Costa J. The fluid dynamic effect on the driving force for a cobalt oxide silica membrane module at high temperatures. Chem Eng Sci 2014. [DOI: 10.1016/j.ces.2014.02.006] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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20
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Wang DK, Diniz da Costa JC, Smart S. Development of rapid thermal processing of tubular cobalt oxide silica membranes for gas separations. J Memb Sci 2014. [DOI: 10.1016/j.memsci.2014.01.014] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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21
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Liu L, Wang DK, Martens DL, Smart S, Strounina E, Diniz da Costa JC. Physicochemical characterisation and hydrothermal stability investigation of cobalt-incorporated silica xerogels. RSC Adv 2014. [DOI: 10.1039/c4ra00498a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
High cobalt oxide concentrations were able to shield the microporous silica network from excessive structural rearrangement during harsh hydrothermal testing.
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Affiliation(s)
- Liang Liu
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
| | - David K. Wang
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane, Australia
| | - Dana. L. Martens
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
| | - Simon Smart
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
| | | | - João C. Diniz da Costa
- The University of Queensland
- FIMLab – Films and Inorganic Membrane Laboratory
- School of Chemical Engineering
- Brisbane, Australia
- Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC)
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Tailoring the oxidation state of cobalt through halide functionality in sol-gel silica. Sci Rep 2013; 3:2449. [PMID: 24022785 PMCID: PMC3769890 DOI: 10.1038/srep02449] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 07/31/2013] [Indexed: 11/25/2022] Open
Abstract
The functionality or oxidation state of cobalt within a silica matrix can be tailored through the use of cationic surfactants and their halide counter ions during the sol-gel synthesis. Simply by adding surfactant we could significantly increase the amount of cobalt existing as Co3O4 within the silica from 44% to 77%, without varying the cobalt precursor concentration. However, once the surfactant to cobalt ratio exceeded 1, further addition resulted in an inhibitory mechanism whereby the altered pyrolysis of the surfactant decreased Co3O4 production. These findings have significant implications for the production of cobalt/silica composites where maximizing the functional Co3O4 phase remains the goal for a broad range of catalytic, sensing and materials applications.
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Scale-Up Design Analysis and Modelling of Cobalt Oxide Silica Membrane Module for Hydrogen Processing. Processes (Basel) 2013. [DOI: 10.3390/pr1020049] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
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Elma M, Yacou C, Diniz da Costa JC, Wang DK. Performance and long term stability of mesoporous silica membranes for desalination. MEMBRANES 2013; 3:136-50. [PMID: 24956942 PMCID: PMC4021940 DOI: 10.3390/membranes3030136] [Citation(s) in RCA: 64] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 07/02/2013] [Accepted: 07/03/2013] [Indexed: 11/16/2022]
Abstract
This work shows the preparation of silica membranes by a two-step sol-gel method using tetraethyl orthosilicate in ethanolic solution by employing nitric acid and ammonia as co-catalysts. The sols prepared in pH 6 resulted in the lowest concentration of silanol (Si–OH) species to improve hydrostability and the optimized conditions for film coating. The membrane was tested to desalinate 0.3–15 wt % synthetic sodium chloride (NaCl) solutions at a feed temperature of 22 °C followed by long term membrane performance of up to 250 h in 3.5 wt % NaCl solution. Results show that the water flux (and salt rejection) decrease with increasing salt concentration delivering an average value of 9.5 kg m–2 h–1 (99.6%) and 1.55 kg m–2 h–1 (89.2%) from the 0.3 and 15 wt % saline feed solutions, respectively. Furthermore, the permeate salt concentration was measured to be less than 600 ppm for testing conditions up to 5 wt % saline feed solutions, achieving below the recommended standard for potable water. Long term stability shows that the membrane performance in water flux was stable for up to 150 h, and slightly reduced from thereon, possibly due to the blockage of large hydrated ions in the micropore constrictions of the silica matrix. However, the integrity of the silica matrix was not affected by the long term testing as excellent salt rejection of >99% was maintained for over 250 h.
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Affiliation(s)
- Muthia Elma
- FIMLab-Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - Christelle Yacou
- FIMLab-Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - João C Diniz da Costa
- FIMLab-Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
| | - David K Wang
- FIMLab-Films and Inorganic Membrane Laboratory, School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia.
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