Comparison of Iron and Aluminum Hydroxy Interlayers in Montmorillonite and Vermiculite: I. Formation

Carstea, D. D.; Harward, M. E.; Knox, Ellis G.

doi:10.2136/sssaj1970.03615995003400030043x

Cited by 52 publications

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“…Earlier work on reaction of smectites with hydroxy Fe(III) cations (Carstea et al, 1970;Herrera & Peech, 1970) indicated that pillared structures were unlikely to form via this route. We have used different reaction conditions but still did not achieve pillaring.…”

Section: Discussionmentioning

confidence: 99%

Preparation and characterization of iron oxide pillared montmorillonite

et al. 1988

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A B S T RA C T : Pillared smectites in which the pillars consist of iron oxide are expected to have interesting and unusual magnetic properties. Several possible routes by which such materials might be made have been investigated, namely intercalation of hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al polycations, phenanthroline-Fe(II) cations, and trinuclear Fe(III) acetato cations into Na-montmorillonite. Only the last of these yielded a pillared clay (PILC) on calcination. The products have been characterized using X-ray powder diffraction and 57Fe M6ssbauer spectroscopy. The precursor Fe-PILC has a d-spacing of 21 A and expands to 23 A on solvation with glycol. The calcined Fe-PILC has a d-spacing of 19 A (gallery height 9.4 A) and does not expand with glycol, confirming cross-linking of the layers. From M6ssbauer spectra at 4.2 K it is estimated that there are of the order of some hundred Fe atoms per pillar.Pillared or cross-linked smectites, in which the interlayer is converted into a two dimensional zeolite-like structure, have recently attracted much interest because of their catalytic and molecular sieving properties (Pinnavaia, 1983;Barrer, 1986). The best understood pillared clays (PILCs) are those in which Al oxide pillars act as molecular-sized props permanently separating the silicate layers of the clay, and the structure of these materials has been investigated using 27A1 and 29Si solid state MAS NMR (Tennakoon et al., 1986;Plee et al., 1985Plee et al., , 1987. If, however, the pillars are formed of Fe oxide instead of A1 oxide, interesting and novel magnetic properties may be expected (Gangas et al., 1985) and M6ssbauer spectroscopy can be utilized to obtain structural information.Metal oxide pillared clays are normally the product of a two step process. The first step is one of cation exchange in which the simple interlayer cation of a smectite (usually Na +) is replaced by a large complex cation. The second step consists of a heat treatment which crosslinks the silicate layers. In this paper, the terms precursor-PILC and calcined-PILC are used in order to make a clear distinction between the products obtained after each step.The complex cation which is used in the preparation of A1-PILCs is the Keggin-like ion [AllaO4(OH)24(H20)12] 7+ (Baes & Mesmer, 1976). In this study we have investigated the PILC-forming potential of a number of large Fe cations which can occupy the exchange sites in smectite interlayers. These are hydroxy-Fe(III) polycations, mixed hydroxy-Fe(III)/Al cations, phenanthroline-Fe(II) complexes and trinuclear Fe(III) carboxylate complexes. CHARACTERISTICS OF METAL OXIDE PILLARED CLAYSIntercalation of complex cations into a smectite followed by heat treatment may, or may not, result in the formation of a PILC. The following three criteria have been used to identify 9 1988 The Mineralogical Society

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Section: Discussionmentioning

confidence: 99%

Preparation and characterization of iron oxide pillared montmorillonite

et al. 1988

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“…Acidic percolating waters in soils mostly activate Al hydroxides to precipitate in the interlayer space of vermiculite, not only in vermiculites of the clay fraction but also in those of the silt fraction (Jackson 1963, Carstea 1968, Carstea et al 1970. Carstea et al (1970) have shown that Al interlayers can be formed in vermiculites, even in a short period of time.…”

Section: Origin Of Clay Minerals In the Fine Fraction Of Tillmentioning

confidence: 99%

“…Carstea et al (1970) have shown that Al interlayers can be formed in vermiculites, even in a short period of time. According to studies of Jackson (1963) and Rich (1968), interlayering appears to form at pH 5.0, at sites where there is low organic matter and frequent wetting and drying.…”

Section: Origin Of Clay Minerals In the Fine Fraction Of Tillmentioning

confidence: 99%

Relationship between mineralogy and the physico-chemical properties of till in central Finland

Räisänen¹,

Tenhola²,

Mäkinen³

1992

Bull Geol Soc Finland

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: Relationship between mineralogy and the physico-chemical properties of till in central Finland. Bull. Geo!. Soc. Finland 64, Part 1,.The chemical and physical characteristics of the fine fraction of till were examined in the area of the Raahe-Ladoga metallogenic belt in central Finland. Till, weathered bedrock and rock samples were collected from the area, where element concentrations of till abruptly ranged from high in an anomalous zone (NE) to low in a non-anomalous zone (SW). The grain size distribution, specific surface area and unit weight, and the leachability of elements measured with several chemical methods were determined from the fine fraction (<0.06 mm) of till. The mineralogical composition of the fine fraction of till and weathered bedrock was established with the X-ray diffraction method (XRD), and the chemical composition of rock samples with the X-ray fluorescence method (XRF).The main factor affecting the increased element concentrations in the anomalous zone is the variation in mica and clay mineral types. The abundance of trioctahedral micas (biotite) and vermiculitic clays carrying most of the trace metals dissolved in aqua regia, has affected to the geochemical pattern of till in the study area. The concentrations of trace metals in the iron precipitates extracted with acid oxalate were too low to be used as evidence of the hydromorphic origin of the anomalous zone. The abundance of main silicates (quartz, feldspars) does not vary much in the fine fraction of till throughout the study area.The absence of the swelling smectite component from the surface layers of till indicates that the source was not the underlying weathered bedrock. The till with a vermiculitic mixed-layer mineral in the anomalous zone contains more material from old sediments weathered during interstadial or interglacial time than does the till with a low clay content in the non-anomalous zone. The abrupt change in the mineralogical and physical properties of till in the study area is suggested to be attributed to the difference in the transport and accumulation dynamics of overburden during deglaciation.

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“…Laboratory studies have also been successful in producing hydroxy interlayers of A1 (Rich, 1968;Goh and Huang, 1986;Barnhisel and Bertsch, 1989), Fe (Carstea et al, 1970;Martin-Luengo et al, 1989), Zr , Ni (Yamanaka and Brindley, 1978), and Cr Carr, 1985). The hydroxy-Cr interlayered montmorillonite prepared by Brindley and Yamanaka (1979) displayed a basal spacing near 16.8/~, considerably larger than the 14.4/~ spacing of chlorite.…”

Section: Introductionmentioning

confidence: 99%

Properties of Hydroxy-Al and -Cr Interlayers in Montmorillonite

Dubbin

Goh

Oscarson

et al. 1994

Clays and clay miner.

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Abstract-In environments contaminated with Cr, the interlayers of expandable layer silicates may serve as sinks for this potentially toxic element. As a means of determining the potential for smectites to serve as sinks for Cr, the precipitation products of A1 and Cr in the interlayers of a montmorillonite were examined. Five montmorillonite (SWy-1) day suspensions were treated with preweighed amounts of AIC13 and CrC13 to give five A1/(AI + Cr) molar ratios (1.0, 0.67, 0.5, 0.33, 0) with a total trivalent cation (M 3+ ) concentration of 600 cmol(+)/kg clay. The clay-cation suspensions were titrated with 0.1 N NaOH to give a NaOH/M 3+ molar ratio of 2.5. Analysis of the solid-phase reaction products showed that the cation exchange capacity and specific surface of all clays were reduced. Chromium reduced the exchangeability of the interlayers while A1 increased the thermal stability. X-ray diffraction analysis revealed that all Al-containing interlayer materials formed similar gibbsite-like polymers. Data from infrared spectroscopy indicated that both AI and Cr were present within the same polymer. Differential thermal analysis and thermogravimetric tracings showed that the rapid collapse of the interlayer in the Cr end-member upon heating was due to a low-temperature loss of hydroxyls. It was not possible to identify all interlayer structures in the Cr end-member. Data from X-ray photoelectron spectroscopy showed all Cr to be Cr(III). Displacement of the interlayer material became more difficult as Cr content increased. The least exchangeable interlayers, therefore, may be found in environments containing the most Cr.

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Comparison of Iron and Aluminum Hydroxy Interlayers in Montmorillonite and Vermiculite: I. Formation

Cited by 52 publications

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Preparation and characterization of iron oxide pillared montmorillonite

Preparation and characterization of iron oxide pillared montmorillonite

Relationship between mineralogy and the physico-chemical properties of till in central Finland

Properties of Hydroxy-Al and -Cr Interlayers in Montmorillonite

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