Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree
The particulate morphology and textural characteristics of nanosilica A–300, initial and hydro-compacted (cA–300) by wetting with various amounts of water in the range of h = 0.5–5.0 g per gram of dry silica, strongly stirred and then dried, have been analyzed using low-temperature 1H NMR sp...
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Chuiko Institute of Surface Chemistry of NAS of Ukraine
2023-02-01
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| Series: | Хімія, фізика та технологія поверхні |
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| author | V. M. Gun’ko V. V. Turov |
| author_facet | V. M. Gun’ko V. V. Turov |
| author_sort | V. M. Gun’ko |
| collection | DOAJ |
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The particulate morphology and textural characteristics of nanosilica A–300, initial and hydro-compacted (cA–300) by wetting with various amounts of water in the range of h = 0.5–5.0 g per gram of dry silica, strongly stirred and then dried, have been analyzed using low-temperature 1H NMR spectroscopy (treated-dried-wetted samples), small angle X-ray scattering, scanning and transmission electron microscopies, infrared spectroscopy, and nitrogen adsorption methods (treated-dried-degassed samples). The effects of the hydro-compaction of A-300 depend strongly on the wetting degree with maximum changes at h = 1.5–2.0 g/g. The wetting degree could be varied to control the reorganization of aggregates of nonporous nanoparticles (NPNP, which are composed of tightly packed adherent proto-particles or nuclei) and agglomerates of aggregates (secondary and ternary structures, respectively), as well as visible particles; i.e., there is a penta-level structural hierarchy of nanosilica with three-level supra-NPNP structures. The hydro-compaction is accompanied by non-monotonic changes in the morphological and textural characteristics of cA–300 vs. h. However, the nanoparticles are much weaker affected by the treatment than higher hierarchical structures. At h ? 1 g/g, the reorganization of aggregate/agglomerate structures does not lead to diminution of the specific surface area (SSA); however, at h ? 1.5 g/g, the SSA value decreases, but the pore volume (estimated from nitrogen adsorption) increases despite the empty volume (estimated from the bulk density rb) of the powder decreases from 21.8 cm3/g for initial A–300 (rb = 0.045 g/cm3) to 3.45 cm3/g on hydro-compaction at h = 4.5 g/g (rb = 0.256 g/cm3), pores become more ordered with a predominant contribution of cylindrical shapes. The textural reorganization of dried hydro-compacted nanosilica is possible again after addition of new water amount. This suggests that the chemical bonds between neighboring nanoparticles do not practically form upon the hydro-compaction and subsequent drying. Thus, hydro-compacted nanosilica loses a dust-forming property (since rb strongly increases), but it remains active with respect to the NPNP mobility, e.g., in aqueous media, and the possibility of the reorganization of the supra-NPNP structures remains under various external actions that is of importance from a practical point of view.
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| format | Article |
| id | doaj-art-a1652ddaba7f430cac9a68a90e6fe6f0 |
| institution | DOAJ |
| issn | 2079-1704 2518-1238 |
| language | English |
| publishDate | 2023-02-01 |
| publisher | Chuiko Institute of Surface Chemistry of NAS of Ukraine |
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| spelling | doaj-art-a1652ddaba7f430cac9a68a90e6fe6f02025-08-20T03:08:31ZengChuiko Institute of Surface Chemistry of NAS of UkraineХімія, фізика та технологія поверхні2079-17042518-12382023-02-0114110.15407/hftp14.01.003Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degreeV. M. Gun’ko0V. V. Turov1Chuiko Institute of Surface Chemistry of National Academy of Sciences of UkraineChuiko Institute of Surface Chemistry of National Academy of Sciences of Ukraine The particulate morphology and textural characteristics of nanosilica A–300, initial and hydro-compacted (cA–300) by wetting with various amounts of water in the range of h = 0.5–5.0 g per gram of dry silica, strongly stirred and then dried, have been analyzed using low-temperature 1H NMR spectroscopy (treated-dried-wetted samples), small angle X-ray scattering, scanning and transmission electron microscopies, infrared spectroscopy, and nitrogen adsorption methods (treated-dried-degassed samples). The effects of the hydro-compaction of A-300 depend strongly on the wetting degree with maximum changes at h = 1.5–2.0 g/g. The wetting degree could be varied to control the reorganization of aggregates of nonporous nanoparticles (NPNP, which are composed of tightly packed adherent proto-particles or nuclei) and agglomerates of aggregates (secondary and ternary structures, respectively), as well as visible particles; i.e., there is a penta-level structural hierarchy of nanosilica with three-level supra-NPNP structures. The hydro-compaction is accompanied by non-monotonic changes in the morphological and textural characteristics of cA–300 vs. h. However, the nanoparticles are much weaker affected by the treatment than higher hierarchical structures. At h ? 1 g/g, the reorganization of aggregate/agglomerate structures does not lead to diminution of the specific surface area (SSA); however, at h ? 1.5 g/g, the SSA value decreases, but the pore volume (estimated from nitrogen adsorption) increases despite the empty volume (estimated from the bulk density rb) of the powder decreases from 21.8 cm3/g for initial A–300 (rb = 0.045 g/cm3) to 3.45 cm3/g on hydro-compaction at h = 4.5 g/g (rb = 0.256 g/cm3), pores become more ordered with a predominant contribution of cylindrical shapes. The textural reorganization of dried hydro-compacted nanosilica is possible again after addition of new water amount. This suggests that the chemical bonds between neighboring nanoparticles do not practically form upon the hydro-compaction and subsequent drying. Thus, hydro-compacted nanosilica loses a dust-forming property (since rb strongly increases), but it remains active with respect to the NPNP mobility, e.g., in aqueous media, and the possibility of the reorganization of the supra-NPNP structures remains under various external actions that is of importance from a practical point of view. https://cpts.com.ua/index.php/cpts/article/view/655hydro-compacted nanosilicawetted nanosilicaparticulate morphologytextural characteristicshierarchical structure reorganization |
| spellingShingle | V. M. Gun’ko V. V. Turov Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree Хімія, фізика та технологія поверхні hydro-compacted nanosilica wetted nanosilica particulate morphology textural characteristics hierarchical structure reorganization |
| title | Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree |
| title_full | Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree |
| title_fullStr | Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree |
| title_full_unstemmed | Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree |
| title_short | Particulate morphology and textural characteristics of nanosilica hydro-compacted at various wetting degree |
| title_sort | particulate morphology and textural characteristics of nanosilica hydro compacted at various wetting degree |
| topic | hydro-compacted nanosilica wetted nanosilica particulate morphology textural characteristics hierarchical structure reorganization |
| url | https://cpts.com.ua/index.php/cpts/article/view/655 |
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