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The x-ray identification and crystal structures of clay minerals
01 Jan 1961-
About: The article was published on 1961-01-01 and is currently open access. It has received 966 citations till now. The article focuses on the topics: Clay minerals.
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TL;DR: In this article, hot caustic leaching extracts the amorphous silica and breaks up the aggregates producing "fines," which are then analyzed with X-ray diffraction techniques.
Abstract: Some of the anauxite grains are single crystals, while others are aggregates. The latter appear to be bound together by an amorphous silica phase. Hot caustic leaching extracts the amorphous silica and breaks up the aggregates producing "fines." Improved characterizations of minor impurities were obtained when the residues from hot caustic treatments were studied with X-ray diffraction techniques.
9 citations
TL;DR: In this article, the McBain equation describing detergency was used to study the process cellulose·clay+detergent= cellulose · detergent+clay·detergence, by taking thoroughly purified cotton, montmorillonite swelling clay, and n−C12H25O (CH2CH2O)−14H as well as other nonionic and anionic detergents.
Abstract: The McBain equation describing detergency was used to study the process cellulose·clay+detergent= cellulose·detergent+clay·detergent, by taking thoroughly purified cotton, montmorillonite swelling clay, and n−C12H25O (CH2CH2O)−14H as well as other nonionic and anionic detergents. The three binary equilibria which add up to this ternary system were also studied. X-ray diffraction showed that monionic detergents sorbed by the clay were intercalated between adjacent, 9.5 A thick lattice layers of clay with their chains parallel to these layers, in sheets one or two molecules thick. The process was accompanied by dehydration and proceeded down to low equilibrium detergent concentrations. The deflocculation of sodium montmorillonite suspensions by polyoxyethylated compounds was shown by an increase in turbidity and decreases in viscosity and sedimentation volume. Cellulose sorbed C12H25O (CH2CH2O)14H reversibly. Its uptake was considerably less than that of clay on a weight basis but was comparable on an area basis. Kaolinite and calcium montmorillonite picked up by cellulose from aqueous suspensions were gradually removed by washing with water, following first-order kinetics. Of the sodium montmorillonite picked up, 0.13±0.01% could not be removed by washing with water. This level of tenaciously retained clay was independent of clay concentration, rate of stirring, and temperature. The ash of fabric treated with sodium montmorillonite was a shrunken replica of the fabric, preserving microscopic details faithfully. This and comparison of the specific surface areas of cotton and sodium montmorillonite indicate that cotton was completely coated with clay to an average depth of three to four lattice layers. The reason for this thickness is that the primary particles in sodium montmorillonite dispersions are packets of three to four lattice layers. Anionic and cationic detergents removed little or none of the 0.13% sodium montmorillonite. Polyoxyethylated and polyoxypropylated compounds removed part but always left behind at least 0.04%. This is the amount of clay required to cover the cellulose surface completely with a sheet of single, nonoverlapping lattice layers. However, when brought into contact in the presence of nonionic detergents, cellulose retained no sodium montmorillonite at all.
9 citations
TL;DR: In this paper, three samples of terra rossa were used as good adsorbents of phosphate (P(V)) from wastewater and removed 29.9-32.6% of P(V) from wastewater.
Abstract: Three samples of terra rossa were good adsorbents of phosphate (P(V)) from wastewater and removed 29.9-32.6% of P(V). The total iron content in terra rossa was the key factor which determined the P(V) removal from wastewater. The original samples of terra rossa were good support materials for the immobilization of metabolically active P(V)-accumulating bacteria Acinetobacter junii (0.56-2.47 x 1010 CFU g-1). The removal of oxalate extractable iron from original sample of terra rossa increased the number of immobilized bacteria to 1.34 x 1011 CFU g-1, which is the highest number of immobilized bacteria reported in the literature so far. In reactors containing the A. junii and terra rossa P(V) was removed from wastewater by simultaneous adsorption onto terra rossa and accumulation inside bacterial cells, resulting in the 40.5-62.5% of P(V) removal. Terra rossa is the promising substrate for the process of biological P(V) removal from wastewater, where it can have dual function: as the adsorbents of P(V) and carrier of P(V)-accumulating bacteria.
9 citations
Additional excerpts
...However, most workers consider terra rossa a polygenetic relict soil, formed during the Tertiary and/or hot and humid periods of the Quaternary (e.g. Altay, 1997; Bronger & Bruhn-Lobin, 1997; Durn et al., 1999)....
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...…composition of terra rossa in the Mediterranean may be very variable and consists of kaolinite, illite, hydroxy-interlayered vermiculite and smectite (e.g. Moresi & Mongelli, 1988; Garcia-Gonzales & Recio, 1988; Boero et al., 1992; Atalay, 1997; Bronger & Bruhn-Lobin, 1997; Durn et al., 1999)....
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TL;DR: In this article, the effects of γ irradiation on vermiculite for the first time were studied using different techniques viz. ultraviolet-visible spectroscopy (UV-Vis), dielectric measurements, X-ray diffraction (XRD), Fourier transform infrared spectroscopic (FTIR), and thermoluminescence (TL).
Abstract: The present work reports the effects of γ irradiation on vermiculite for the first time. The radiation-induced changes of vermiculite were studied using different techniques viz. ultraviolet-visible spectroscopy (UV-Vis), dielectric measurements, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and thermoluminescence (TL). In UV-Vis analysis, the Cody model was employed to calculate structural disorder from Urbach energy, which explained the variation of the optical band gap (direct and indirect) with different (1–2000 kGy) γ doses. XRD analysis of the pristine and irradiated samples shows that the crystallinity improved upon irradiation at γ dose up to 1000 kGy and deteriorated on further increase of the γ dose. A significant change was observed in the dielectric properties after γ irradiation. Data shows that ac conductivity is proportional to the nth power of frequency ( f n ) in pristine and irradiated vermiculite, with a slope n ranging between 0.52 and 0.76, which indicates that electronic conduction takes place through an electron hopping process. No appreciable changes in characteristic bands (FTIR) have been observed after irradiation, indicating that natural vermiculite is chemically stable. A well-defined TL peak around 132 °C and enhancement in its intensity with γ dose (1–1000 kGy) make vermiculite a perfect thermoluminescence dosimeter and indicates usefulness applications in radiation dosimetry.
9 citations
Cites background from "The x-ray identification and crysta..."
...…gamma irradiation, optical properties, dielectric properties, XRD, FTIR, thermoluminescence introduction Natural vermiculite is a constituent of the phyllosilicate or sheet silicate group of minerals including Al2O3, H2O, MgO, FeO, and SiO2, which resembles mica in appearance (Brown 1961)....
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