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Dong S, Liu L, Ling NNA, May EF, Johns ML, Robinson N. Toward Quantifying the Chemical Sensitivity of Nuclear Spin Surface Relaxivity in Mesoporous Media. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:16160-16171. [PMID: 39045723 DOI: 10.1021/acs.langmuir.4c01245] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/25/2024]
Abstract
Low-field nuclear magnetic resonance (NMR) relaxation is a promising non-invasive technique for characterizing solid-liquid interactions within functional porous materials. However, the ability of the solid-liquid interface to enhance adsorbate relaxation rates, known as the surface relaxivity, in the case of different solvents and reagents involved in various chemical processes has yet to be evaluated in a quantitative manner. In this study, we systematically explore the surface relaxation characteristics of 10 liquid adsorbates (cyclohexane, acetone, water, and 7 alcohols, including ethylene glycol) confined within mesoporous silicas with pore sizes between 6 and 50 nm using low-field (12.7 MHz) two-dimensional 1H T1-T2 relaxation measurements. Functional-group-specific relaxation phenomena associated with the alkyl and hydroxyl groups of the confined alcohols are clearly distinguished; we report the dependence of both longitudinal (T1) and transverse (T2) relaxation rates of these 1H-bearing moieties on pore surface-to-volume ratio, facilitating the quantification and assignment of surface relaxivity values to specific functional groups within the same adsorbate molecule for the first time. We further demonstrate that alkyl group transverse surface relaxivities correlate strongly with the alkyl/hydroxyl ratio of the adsorbates assessed, providing evidence for a simple, quantitative relationship between surface relaxivity and interfacial chemistry. Overall, our observations highlight potential pitfalls in the application of NMR relaxation for the evaluation of pore size distributions using hydroxylated probe molecules, and provide motivation for the exploration of nuclear spin relaxation measurements as a route to adsorbate identity within functional porous materials.
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Affiliation(s)
- Shuang Dong
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
- Key Laboratory of Ocean Energy Utilization and Energy Conservation of Ministry of Education, Dalian University of Technology, Dalian, Liaoning 116024, People's Republic of China
| | - Libin Liu
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Nicholas N A Ling
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Eric F May
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Michael L Johns
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
| | - Neil Robinson
- Department of Chemical Engineering, The University of Western Australia, Perth, Western Australia 6009, Australia
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2
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Bozkurt OD, Toraman HE. Conversion of Polypropylene into Light Hydrocarbons and Aromatics by Metal Exchanged Zeolite Catalysts. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2024; 40:9636-9650. [PMID: 38654550 DOI: 10.1021/acs.langmuir.4c00453] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/26/2024]
Abstract
Polyolefins can be converted into C2-C5 hydrocarbons and benzene-toluene-xylene (BTX) aromatics as high-demand petrochemical feedstocks via catalytic pyrolysis on acidic zeolites. Bro̷nsted and Lewis acid sites are responsible for cracking polyolefins into olefins and subsequent aromatic formation. In this study, we have subjected the parent HZSM-5 zeolite to postsynthetic partial metal exchange with Fe, Co, Ni, Cu, and Ce cations to perturb Bro̷nsted/Lewis acidity. We have investigated these metal-modified HZSM-5 on the catalytic pyrolysis of polypropylene (PP) in a micropyrolyzer connected to a two-dimensional gas chromatograph coupled to a time-of-flight mass spectrometer and flame ionization detector (Tandem Pyrolyzer-GC × GC-TOF-MS/FID setup). Whereas Fe-, Co-, Cu-, and Ce-exchanged zeolites (with 2.5, 2.3, 1.9, and 0.8 wt % metal, respectively) had comparable product yields with the parent zeolite, Ni-exchanged zeolites with Ni content of 0.5 to 2 wt % were associated with enhanced BTX formation (28-38 wt %) compared to that of the parent zeolite (22 wt %). Pyridine-FTIR indicated that the Bro̷nsted/Lewis acid ratio of the parent zeolite decreased upon metal ion exchange. According to Pyridine-TPD, the parent zeolite's medium-strength acid sites were redistributed into weak and strong acid sites in Ni-exchanged zeolites. The higher amount of carbon deposits on Ni-exchanged zeolites compared to the parent and other metal ion exchanged zeolites was attributed to the enhanced aromatization activity by the simultaneous decrease in the Bro̷nsted/Lewis acid ratio and emergence of strong acid sites.
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Affiliation(s)
- Ozge Deniz Bozkurt
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hilal Ezgi Toraman
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Energy and Mineral Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Institute of Energy and the Environment, Pennsylvania State University, University Park, Pennsylvania 16802, United States
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3
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Suekuni MT, Allgeier AM. Correlating Surface Chemistry to Surface Relaxivity via TD-NMR Studies of Polymer Particle Suspensions. JACS AU 2023; 3:2826-2834. [PMID: 37885588 PMCID: PMC10598564 DOI: 10.1021/jacsau.3c00384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2023] [Revised: 08/29/2023] [Accepted: 09/19/2023] [Indexed: 10/28/2023]
Abstract
This study elucidates the impact of surface chemistry on solvent spin relaxation rates via time-domain nuclear magnetic resonance (TD-NMR). Suspensions of polymer particles of known surface chemistry were prepared in water and n-decane. Trends in solvent transverse relaxation rates demonstrated that surface polar functional groups induce stronger interactions with water with the opposite effect for n-decane. NMR surface relaxivities (ρ2) calculated for the solid-fluid pairs ranged from 0.4 to 8.0 μm s-1 and 0.3 to 5.4 μm s-1 for water and n-decane, respectively. The values of ρ2 for water displayed an inverse relationship to contact angle measurements on surfaces of similar composition, supporting the correlation of the TD-NMR output with polymer wettability. Surface composition, i.e., H/C ratios and heteroatom content, mainly contributed to the observed surface relaxivities compared to polymer % crystallinity and mean particle sizes via multiple linear regression. Ultimately, these findings emphasize the significance of surface chemistry in TD-NMR measurements and provide a quantitative foundation for future research involving TD-NMR investigations of wetted surface area and fluid-surface interactions. A comprehensive understanding of the factors influencing solvent relaxation in porous media can aid the optimization of industrial processes and the design of materials with enhanced performance.
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Affiliation(s)
- Murilo T Suekuni
- Department of Chemical and Petroleum Engineering, The Center for Environmentally Beneficial Catalysis, and The Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
| | - Alan M Allgeier
- Department of Chemical and Petroleum Engineering, The Center for Environmentally Beneficial Catalysis, and The Institute for Sustainable Engineering, University of Kansas, Lawrence, Kansas 66045, United States
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4
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Wang W, Zhou W, Tang Y, Cao W, Docherty SR, Wu F, Cheng K, Zhang Q, Copéret C, Wang Y. Selective Oxidation of Methane to Methanol over Au/H-MOR. J Am Chem Soc 2023. [PMID: 37267262 DOI: 10.1021/jacs.3c04260] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Selective oxidation of methane to methanol by dioxygen (O2) is an appealing route for upgrading abundant methane resource and represents one of the most challenging reactions in chemistry due to the overwhelmingly higher reactivity of the product (methanol) versus the reactant (methane). Here, we report that gold nanoparticles dispersed on mordenite efficiently catalyze the selective oxidation of methane to methanol by molecular oxygen in aqueous medium in the presence of carbon monoxide. The methanol productivity reaches 1300 μmol gcat-1 h-1 or 280 mmol gAu-1 h-1 with 75% selectivity at 150 °C, outperforming most catalysts reported under comparable conditions. Both hydroxyl radicals and hydroperoxide species participate in the activation and conversion of methane, while it is shown that the lower affinity of methanol on gold mainly accounts for higher methanol selectivity.
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Affiliation(s)
- Wangyang Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Wei Zhou
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Yuchen Tang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Weicheng Cao
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
- Department of Chemistry, Zhejiang University, Hangzhou 310027, China
| | - Scott R Docherty
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Fangwei Wu
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Kang Cheng
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Qinghong Zhang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Christophe Copéret
- Department of Chemistry and Applied Biosciences, ETH Zürich, Vladimir-Prelog-Weg 2, CH-8093 Zürich, Switzerland
| | - Ye Wang
- State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials, National Engineering Laboratory for Green Chemical Productions of Alcohols, Ethers and Esters, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
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Valiya Parambathu A, Chapman WG, Hirasaki GJ, Asthagiri D, Singer PM. Effect of Nanoconfinement on NMR Relaxation of Heptane in Kerogen from Molecular Simulations and Measurements. J Phys Chem Lett 2023; 14:1059-1065. [PMID: 36693239 DOI: 10.1021/acs.jpclett.2c03699] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
Kerogen-rich shale reservoirs will play a key role during the energy transition, yet the effects of nanoconfinement on the NMR relaxation of hydrocarbons in kerogen are poorly understood. We use atomistic MD simulations to investigate the effects of nanoconfinement on the 1H NMR relaxation times T1 and T2 of heptane in kerogen. In the case of T1, we discover the important role of confinement in reducing T1 by ∼3 orders of magnitude from that of bulk heptane, in agreement with measurements of heptane dissolved in kerogen from the Kimmeridge Shale, without any models or free parameters. In the case of T2, we discover that confinement breaks spatial isotropy and gives rise to residual dipolar coupling which reduces T2 by ∼5 orders of magnitude from the value for bulk heptane. We use the simulated T2 to calibrate the surface relaxivity and thence predict the pore-size distribution of the organic nanopores in kerogen, without additional experimental data.
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Affiliation(s)
- Arjun Valiya Parambathu
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
- Department of Chemical and Biomolecular Engineering, University of Delaware, 150 Academy Street, Newark, Delaware19716, United States
| | - Walter G Chapman
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
| | - George J Hirasaki
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
| | - Dilipkumar Asthagiri
- Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, Tennessee37830-6012, United States
| | - Philip M Singer
- Department of Chemical and Biomolecular Engineering, Rice University, 6100 Main Street, Houston, Texas77005, United States
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Jardón-Álvarez D, Malka T, van Tol J, Feldman Y, Carmieli R, Leskes M. Monitoring electron spin fluctuations with paramagnetic relaxation enhancement. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2022; 336:107143. [PMID: 35085928 DOI: 10.1016/j.jmr.2022.107143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
The magnetic interactions between the spin of an unpaired electron and the surrounding nuclear spins can be exploited to gain structural information, to reduce nuclear relaxation times as well as to create nuclear hyperpolarization via dynamic nuclear polarization (DNP). A central aspect that determines how these interactions manifest from the point of view of NMR is the timescale of the fluctuations of the magnetic moment of the electron spins. These fluctuations, however, are elusive, particularly when electron relaxation times are short or interactions among electronic spins are strong. Here we map the fluctuations by analyzing the ratio between longitudinal and transverse nuclear relaxation times T1/T2, a quantity which depends uniquely on the rate of the electron fluctuations and the Larmor frequency of the involved nuclei. This analysis enables rationalizing the evolution of NMR lineshapes, signal quenching as well as DNP enhancements as a function of the concentration of the paramagnetic species and the temperature, demonstrated here for LiMg1-xMnxPO4 and Fe(III) doped Li4Ti5O12, respectively. For the latter, we observe a linear dependence of the DNP enhancement and the electron relaxation time within a temperature range between 100 and 300 K.
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Affiliation(s)
- Daniel Jardón-Álvarez
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tahel Malka
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johan van Tol
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States
| | - Yishay Feldman
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raanan Carmieli
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Leskes
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
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Yang K, Sadeghi Pouya E, Liu L, Li M, Yang X, Robinson N, May EF, Johns ML. Low‐Field NMR Relaxation Analysis of High‐Pressure Ethane Adsorption in Mesoporous Silicas. Chemphyschem 2022; 23:e202100794. [DOI: 10.1002/cphc.202100794] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Revised: 12/20/2021] [Indexed: 12/11/2022]
Affiliation(s)
- Kaishuo Yang
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Ehsan Sadeghi Pouya
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Libin Liu
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Ming Li
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Xiaoxian Yang
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Neil Robinson
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Eric F. May
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
| | - Michael L. Johns
- Department of Chemical Engineering The University of Western Australia 35 Stirling Highway (M050) Perth WA 6009 Australia
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8
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Rivet Q, Meyet J, Rivallan M, Nardin T, Farrusseng D. Characterization of the Brønsted acidity of PtSn/Al 2O 3 surfaces by adsorption of 2,6-di- tert-butylpyridine. NEW J CHEM 2022. [DOI: 10.1039/d2nj00602b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The characterization of acid sites on solid catalysts is a key to understanding reaction mechanisms at the molecular level.
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Affiliation(s)
- Quentin Rivet
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON−UMR 5256, 69626 Villeurbanne Cedex, France
- IFP Energies nouvelles, Rond-point de l’échangeur de Solaize, 69360, Solaize, France
| | - Jordan Meyet
- IFP Energies nouvelles, Rond-point de l’échangeur de Solaize, 69360, Solaize, France
| | - Mickaël Rivallan
- IFP Energies nouvelles, Rond-point de l’échangeur de Solaize, 69360, Solaize, France
| | - Thibaud Nardin
- IFP Energies nouvelles, Rond-point de l’échangeur de Solaize, 69360, Solaize, France
| | - David Farrusseng
- Université de Lyon, Université Claude Bernard Lyon 1, CNRS, IRCELYON−UMR 5256, 69626 Villeurbanne Cedex, France
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Robinson N, May EF, Johns ML. Low-Field Functional Group Resolved Nuclear Spin Relaxation in Mesoporous Silica. ACS APPLIED MATERIALS & INTERFACES 2021; 13:54476-54485. [PMID: 34743514 DOI: 10.1021/acsami.1c13934] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Solid-fluid interactions underpin the efficacy of functional porous materials across a diverse array of chemical reaction and separation processes. However, detailed characterization of interfacial phenomena within such systems is hampered by their optically opaque nature. Motivated by the need to bridge this capability gap, we report low-magnetic-field two-dimensional (2D) 1H nuclear spin relaxation measurements as a noninvasive probe of adsorbate identity and interfacial dynamics, exploring the relaxation characteristics exhibited by liquid hydrocarbon adsorbates confined to a model mesoporous silica. For the first time, we demonstrate the capacity of this approach in distinguishing functional group-specific relaxation phenomena across a diverse range of alcohols and carboxylic acids employed as solvents, reagents, and liquid hydrogen carriers, with distinct relaxation responses assigned to the alkyl and hydroxyl moieties of each confined liquid. Uniquely, this relaxation behavior is shown to correlate with adsorbate acidity, with the observed relationship rationalized on the basis of surface-adsorbate proton-exchange dynamics. Our results demonstrate that nuclear spin relaxation provides a molecular-level perspective on sorbent/sorbate interactions, motivating the exploration of such measurements as a unique probe of adsorbate identity within optically opaque porous media.
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Affiliation(s)
- Neil Robinson
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Eric F May
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
| | - Michael L Johns
- Department of Chemical Engineering, University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia
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YURDAKOÇ MK, BÖLÜK H, ALTINIŞIK TAĞAÇ A. Surface Acidities of Bentonite, Sepiolite, and Synthetic Silica-Aluminas. JOURNAL OF THE TURKISH CHEMICAL SOCIETY, SECTION A: CHEMISTRY 2021. [DOI: 10.18596/jotcsa.962665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022] Open
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