Novel anhydrous unfolded structure by heating of acid pre-treated sepiolite

Valentín, Juan López; López-Manchado, M.A.; Rodrı́guez, A.; Posadas, Paula; Ibarra, L.

doi:10.1016/j.clay.2006.10.005

Cited by 73 publications

(61 citation statements)

References 47 publications

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“…Both specimens have the features of sepiolite minerals, but their peak intensities are different, particularly for sepiolite and quartz phases. A decrease in the intensity of the characteristic peaks of the sepiolite, particularly at the maximum 2h = 7.27°, and a sharp change in the increase peak of the quartz are distinct after acid treatment, in agreement with observations [10,13] that a progressive elimination of sepiolite structure and formation of silica occurs during acid treatment. In addition, acid treatment could also eliminate mineral impurities and remove metal-exchange cations.…”

Section: Resultssupporting

confidence: 84%

Hydrothermal synthesis of porous materials from sepiolite

Wang

Jing

et al. 2011

Res Chem Intermed

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In order not only to manufacture a tough porous material from sepiolite but also to sustain the inherent properties of the sepiolite, a hydrothermal experiment was carried out under saturated steam pressure at 473 K for up to 24 h by mixing slaked lime. The experimental results show that the addition of slaked lime exerts a positive effect on the strength development, and the strength enhancement is found to be due to tobermorite and calcium silicate hydrate (CSH) gel formation. Curing time seems to condition the strength development. A fine particle size of sepiolite improves its activity during the hydrothermal process, thus offering a higher strength and quicker hardening rate of the synthesized specimen. The acid activation also has a beneficial effect on the strength development. The hardening mechanism of the synthesized specimen is different between the specimens synthesized with or without acid activation. The strength enhancement for sepiolite with acid activating is due mainly to CSH gel formation, instead of tobermorite formation without acid activation.

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Section: Resultssupporting

confidence: 84%

Hydrothermal synthesis of porous materials from sepiolite

Wang

Jing

et al. 2011

Res Chem Intermed

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“…To obtain completely anhydrous SEP with empty and open channels, heat treatment is necessary. Earlier reports [22,26] showed that the activated SEP (up to 550 • C) had a higher thermodynamical stability compared with the raw-SEP (below 200 • C). Thus, heat treatment was conducted at 300 • C using the acidactivated SEP in this study.…”

Section: Characterization Of the Ah-sep And Oah-sep Powdersmentioning

confidence: 95%

“…The preparation of acid (hydrochloric acid, HCl) activated SEP was carried out following a former report [22]. Then the acidactivated SEP was heated at 300 • C for 2 h in a muffle roaster, and the acid and heat pretreated SEP was designated as AH-SEP.…”

Section: Preparation and Characterization Of The Msep Powdersmentioning

confidence: 99%

Preparation of polyethersulfone-modified sepiolite hybrid particles for the removal of environmental toxins

Cheng

Ren

et al. 2011

Chemical Engineering Journal

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“…Furthermore, the absorption peaks at 1197, 1088, 1028, and 980 cm −1 , ascribed to the fingerprints of APT [22,23], also gradually disappeared with rising the temperature. This implies the tetrahedral-octahedral skeleton structure of APT was broken due to the removal of water [24]. In other words, the calcination temperature should not be too high for keeping the structure of APT.…”

Section: Characterization Of Compositesmentioning

confidence: 96%