Infrared Study of Attapulgite and HCl Treated Attapulgite

Abstract

Abstract--Infrared absorption spectra show important changes in the positions and form of the absorption bands of a film of attapulgite after it has been pumped out. An attempt to differentiate among some of the multiple frequencies due to OH groups is based on the information obtained from dehydration and deuteration experiments. The 1198 cm -~ shoulder, characteristic of attapulgite, is assigned to a Si-O vibration. When attapulgite is refluxed with 5N HCI for 5 hr the octahedral layer is dissolved. The acid attack causes the disappearance of the Si-O-Si absorption bands from attapulgite giving rise to a characteristic vibration at 1090 cm -~, as well as another absorption at 960 cm -1. The latter indicates the presence of silanol groups. INTRODUCTION THE i.r. spectra of attapulgite have been reported by Gonzalez Garcia et al. (1956) and by Otsuka et al. (1968). Also, infrared studies of heated attapulgite have been published (Ovcharenko, 1966;Hayashi et al., 1969;Taracevich, 1970).The object of this work is to present additional information on the behavior of attapulgite when evacuated. Moreover, some interpretations regarding the frequencies of the OH groups are based on isotopic exchange experiments.Another aspect of this work deals with the modification of attapulgite upon HC1 attack. I.R. spectra of HC1 treated attapulgite have not been previously reported.

Asbestiform sepiolite coated by aliphatic hydrocarbons from Perletoa, Aosta Valley Region (Western Alps, Italy): characterization, genesis and possible hazards

“…Data are consistent with previous works (Cannings, 1968;Hayashi et al, 1969;Mendelovici, 1973;Nagata et al, 1974;Prost, 1975;Mendelovici and Portillo, 1976;Post, 1978;Myriam et al, 1998;Frost et al, 2001;Jung and Grange, 2004;Ovarlez et al, 2009;Giustetto et al, 2010;Giustetto et al, 2011b;Bukas et al, 2013). Attribution of vibrational modes and related evolution with T rise are summarized in Table 3.…”

The increase of surface area of a Brazilian palygorskite clay activated with sulfuric acid solutions using a factorial design

“…The present study encountered this band between 970 cm -1 and 978 cm -1 . 18,19 . Table 3 shows the BET surface area and pore volume results for samples of the factorial design.…”

“…In acid solution, the protons (H + ) react with the octahedral cations such as Al, Fe, Mg and they are released to the solution. The acid cleans the structural channels but an undesirable leaching can also occur, depending on the activation's parameters [18][19][20][21] . The goal of this work was to remove impurities aggregated to the clay and to activate the palygorskite by sulfuric acid treatment, using a factorial design method, in order to determine the influence of activation parameters.…”

FTIR spectroscopic study of palygorskite: Influence of the composition of the octahedral sheet

“…4c). Mendelovici (1973) reported this peak as charac teristic of palygorskite. It is important to note that it does not appear in other clay silicates, except in sepi olite.…”

“…This peak is not present in the LIS sample, while in the TOR sample it appears with the highest intensity. Mendelovici (1973) found a peak at 3590 cm 1 which shifts to 3570 cm 1 on heating, and Shuali et al (1987) and Augsburger et al (1998) assigned the weak band at 3580 cm 1 to coordinated water molecules in the channels. Sema et al (1977) attributed this band to Al-Fe 3+ -OH or Al-Mg-OH bonds, while Chahi et al (2002), based on comparison with smectite, attributed it to Al-Fe-OH stretching.…”