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פותח על ידי קלירמאש פתרונות בע"מ -
Thermal analysis of hexadecyltrimethylammonium-montmorillonites : Part 2. Thermo-XRD-spectroscopy-analysis
Year:
2011
Authors :
בוריסובר, מיכאל
;
.
Volume :
105
Co-Authors:
Lapides, I., Institute of Chemistry, Hebrew University of Jerusalem, Campus Edmund Y. Safra, Jerusalem 91904, Israel
Borisover, M., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, POB 6, Bet Dagan 50250, Israel
Yariv, S., Institute of Chemistry, Hebrew University of Jerusalem, Campus Edmund Y. Safra, Jerusalem 91904, Israel
Facilitators :
From page:
39
To page:
51
(
Total pages:
13
)
Abstract:
Na-montmorillonite (Na-MONT) was loaded with hexadecyltrimethylammonium cations (HDTMA) by replacing 41 and 90% of the exchangeable Na with HDTMA. The organoclays were labeled OC-41 and OC-90, respectively. Freeze-dried Na-MONT, OC-41, and OC-90 were heated in air at 150, 250, 360, 420, 550, 700, and 900 °C. The thermally treated samples were suspended in water, air-dried, and desiccated over silica during 40 days. All samples were diffracted by X-ray and fitting calculations were performed on each diffractogram. These calculations gave information on basal spacings, relative concentrations, and homogeneity of the different tactoids obtained at each temperature, before and after suspending and desiccating. HDTMA-MONT tactoids with spacing ≥1.41 nm appeared between 25 and 250 °C. OC-41 or OC-90 intercalated monolayers or bilayers of HDTMA, respectively. At 250 °C OC-41 was air-oxidized to a smaller extent than OC-90, resulting in charcoal-MONT tactoids. With further heating the organic matter was gradually oxidized and at 700 °C both clays were collapsed. During the thermo-XRD-analysis of both organoclays three types of charcoal-MONT complexes appeared: (1) LTSC-MONT tactoids with a basal spacing 1.32-1.39 nm, between 250 and 420 °C in both clays; (2) HTSC-α-MONT tactoids with spacing 1.22-1.28 nm, between 360 or 250 and 500 or 550 °C in OC-41 or OC-90, respectively; (3) HTSC-β-MONT with spacing 1.12-1.18 nm, between 360 and 550 °C in both clays, where LTSC and HTSC are low- and high-temperature stable charcoal, respectively. HTSC-β-MONT differs from HTSC-α-MONT by having carbon atoms keying into the ditrigonal holes of the clay-O-planes. © 2011 Akadémiai Kiadó, Budapest, Hungary.
Note:
Related Files :
Basal spacing
Clay minerals
Hexadecyltrimethylammonium
high temperature
Na-montmorillonite
Silica
Tactoids
עוד תגיות
תוכן קשור
More details
DOI :
10.1007/s10973-011-1389-9
Article number:
0
Affiliations:
Database:
סקופוס
Publication Type:
מאמר
;
.
Language:
אנגלית
Editors' remarks:
ID:
31123
Last updated date:
02/03/2022 17:27
Creation date:
17/04/2018 00:59
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Scientific Publication
Thermal analysis of hexadecyltrimethylammonium-montmorillonites : Part 2. Thermo-XRD-spectroscopy-analysis
105
Lapides, I., Institute of Chemistry, Hebrew University of Jerusalem, Campus Edmund Y. Safra, Jerusalem 91904, Israel
Borisover, M., Institute of Soil, Water and Environmental Sciences, Volcani Center, Agricultural Research Organization, POB 6, Bet Dagan 50250, Israel
Yariv, S., Institute of Chemistry, Hebrew University of Jerusalem, Campus Edmund Y. Safra, Jerusalem 91904, Israel
Thermal analysis of hexadecyltrimethylammonium-montmorillonites : Part 2. Thermo-XRD-spectroscopy-analysis
Na-montmorillonite (Na-MONT) was loaded with hexadecyltrimethylammonium cations (HDTMA) by replacing 41 and 90% of the exchangeable Na with HDTMA. The organoclays were labeled OC-41 and OC-90, respectively. Freeze-dried Na-MONT, OC-41, and OC-90 were heated in air at 150, 250, 360, 420, 550, 700, and 900 °C. The thermally treated samples were suspended in water, air-dried, and desiccated over silica during 40 days. All samples were diffracted by X-ray and fitting calculations were performed on each diffractogram. These calculations gave information on basal spacings, relative concentrations, and homogeneity of the different tactoids obtained at each temperature, before and after suspending and desiccating. HDTMA-MONT tactoids with spacing ≥1.41 nm appeared between 25 and 250 °C. OC-41 or OC-90 intercalated monolayers or bilayers of HDTMA, respectively. At 250 °C OC-41 was air-oxidized to a smaller extent than OC-90, resulting in charcoal-MONT tactoids. With further heating the organic matter was gradually oxidized and at 700 °C both clays were collapsed. During the thermo-XRD-analysis of both organoclays three types of charcoal-MONT complexes appeared: (1) LTSC-MONT tactoids with a basal spacing 1.32-1.39 nm, between 250 and 420 °C in both clays; (2) HTSC-α-MONT tactoids with spacing 1.22-1.28 nm, between 360 or 250 and 500 or 550 °C in OC-41 or OC-90, respectively; (3) HTSC-β-MONT with spacing 1.12-1.18 nm, between 360 and 550 °C in both clays, where LTSC and HTSC are low- and high-temperature stable charcoal, respectively. HTSC-β-MONT differs from HTSC-α-MONT by having carbon atoms keying into the ditrigonal holes of the clay-O-planes. © 2011 Akadémiai Kiadó, Budapest, Hungary.
Scientific Publication
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