Clays and Clay Minerals
About: Clays and Clay Minerals is an academic journal. The journal publishes majorly in the area(s): Kaolinite & Illite. It has an ISSN identifier of 0009-8604. Over the lifetime, 4052 publication(s) have been published receiving 156153 citation(s).
Topics: Kaolinite, Illite, Clay minerals, Montmorillonite, Adsorption
Papers published on a yearly basis
01 Feb 1958-Clays and Clay Minerals
TL;DR: In this article, the bicarbonate-buffered Na2S2O4-citrate system was used for removing free iron oxides from latosolic soils, and the least destructive of iron silicate clays.
Abstract: The oxidation potential of dithionite (Na2S2O4) increases from 0.37 V to 0.73 V with increase in pH from 6 to 9, because hydroxyl is consumed during oxidation of dithionite. At the same time the amount of iron oxide dissolved in 15 minutes falls off (from 100 percent to less than 1 percent extracted) with increase in pH from 6 to 12 owing to solubility product relationships of iron oxides. An optimum pH for maximum reaction kinetics occurs at approximately pH 7.3. A buffer is needed to hold the pH at the optimum level because 4 moles of OH are used up in reaction with each mole of Na2S2O4 oxidized. Tests show that NaHCO3 effectively serves as a buffer in this application. Crystalline hematite dissolved in amounts of several hundred milligrams in 2 min. Crystalline goethite dissolved more slowly, but dissolved during the two or three 15 min treatments normally given for iron oxide removal from soils and clays. A series of methods for the extraction of iron oxides from soils and clays was tested with soils high in free iron oxides and with nontronite and other iron-bearing clays. It was found that the bicarbonate-buffered Na2S2O4-citrate system was the most effective in removal of free iron oxides from latosolic soils, and the least destructive of iron silicate clays as indicated by least loss in cation exchange capacity after the iron oxide removal treatment. With soils the decrease was very little but with the very susceptible Woody district nontronite, the decrease was about 17 percent as contrasted to 35–80 percent with other methods.
01 Aug 1983-Clays and Clay Minerals
TL;DR: Ion exchange isotherms between hydrotalcite-like (HT) ions were determined and the spacing and width of the 003 reflection were measured as a function of HT composition as mentioned in this paper.
Abstract: Ion-exchange isotherms between hydrotalcite-like (HT) of the NO3-, CI-, and SO4- forms and F , 0% Br , I , OH-, SO42-, CO3 z-, and Naphthol Yellow S (NYS 2-) ions were determined, and the spacing and the width of the 003 reflection were measured as a function of HT composition The ion-exchange equilibrium constant for HTs of monovalent anions are in the sequence OH- > F > Cl > Br- > NO3- > I , those for divalent anions are in the sequence CO3 ~- > NYS z- > SO42- The ion-exchange equilibrium constants tend to increase as the diameters of the anions decrease, and the crystallite size in the 001 direction tends to increase with anions having higher selectivity The OH-form of HT has the smallest basal spacing and the largest crystallite size in the 001 direction
01 Aug 1990-Clays and Clay Minerals
TL;DR: Elliott et al. as discussed by the authors used X-ray Diffraction and the Identification and Analysis of Clay Minerals to identify and analyze the properties of clays in the soil.
Abstract: Instructor: Dr. W. Crawford Elliott, Associate Professor, Department Chair Office: 331 Kell Hall Office Phone: (404) 413-5756 E-mail: email@example.com Primary Texts: X-ray Diffraction and the Identification and Analysis of Clay Minerals, by D.M. Moore and Robert C. Reynolds, Jr. (2nd Edition), 1997, Oxford University Press. Office Hours: 4-5 pm M, anytime the door is open, or by appointment. Lectures: M, W, 5:30pm – 7:10 pm, Kell 314. Laboratory: By arrangement, see below.
01 Oct 2001-Clays and Clay Minerals
TL;DR: The interpretation of the absorption spectra of the Source Clays in the middle-IR (MIR) region (4000-400 cm−1) given here follows those of Farmer and Russell (1964), Farmer (1974a, 1979) and Russell and Fraser (1994).
Abstract: Infrared (IR) spectroscopy has a long and successful history as an analytical technique and is used extensively (McKelvy et al., 1996; Stuart, 1996). It is mainly a complementary method to X-ray diffraction (XRD) and other methods used to investigate clays and clay minerals. It is an economical, rapid and common technique because a spectrum can be obtained in a few minutes and the instruments are sufficiently inexpensive as to be available in many laboratories. An IR spectrum can serve as a fingerprint for mineral identification, but it can also give unique information about the mineral structure, including the family of minerals to which the specimen belongs and the degree of regularity within the structure, the nature of isomorphic substituents, the distinction of molecular water from constitutional hydroxyl, and the presence of both crystalline and non-crystalline impurities (Farmer, 1979). The interpretation of the absorption spectra of the Source Clays in the middle-IR (MIR) region (4000–400 cm−1) given here follows those of Farmer and Russell (1964), Farmer (1974a, 1979) and Russell and Fraser (1994). In addition, reflectance spectra in the near-IR (NIR) region (11,000–4000 cm−1), where overtones and combination vibrations occur, are included. These spectra provide information on structural OH groups and H2O in clay minerals (Bishop et al., 1994; Frost and Johansson, 1998; Petit et al., 1999a) which may not be clearly observed in the MIR spectra. Small changes in stretching and bending band positions are additive in the combination bands, thereby making them more readily differentiated (Post and Noble, 1993). Dispersive IR spectrometers are slowly being replaced by quicker and more sensitive Fourier transform (FT) instruments (Rintoul et al., 1998). The greater sensitivity of the FTIR spectrometers is related to the continuous detection of the entire transmitted energy …
01 Oct 1975-Clays and Clay Minerals
TL;DR: The basic salts of this system were prepared and their structures and physico-chemical properties were studies by electron microscopy, chemical analysis, X-ray powder diffraction, thermal analysis, and acidity-basicity measurements as mentioned in this paper.
Abstract: The basic salts of this system were prepared and their structures and physico-chemical properties were studies by electron microscopy, chemical analysis, X-ray powder diffraction, thermal analysis, i.r. absorption spectra, BET absorption, and acidity-basicity measurements. The salts were found to be new compounds analogous to hydrotalcite. They can be expressed by the formula; [M 2+ M 3+ (OH)2(x+y))]y+ [A 1 − , Az2- · mH2O]-(z1 + 2z2) where M2+ and M3+ denote di- and trivalent cations, A− and A2− denote mono- and divalent anions, respectively, and y = z1 + 2z2; z1 ≫ z2. The structures consist of positively charged Cd(OH)2-like basic layers and intermediate layers formed from anions and water molecules with the solid solution of divalent cation (M2+) and trivalent cation (M3+) being formed in the range of 0.6 > x/(x + y) > 0.9. The anions of Cl−, NO 3 − and ClO 4 − are easily substituted by CO 3 2− . A large part of the NO 3 − makes a monodentate-type bond and the ClO 4 − a bridge-type bond.
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