A unique vanadium-titanium-bearing mixed-layered clay is currently being mined as an ore of vanadium at Potash Sulphur Springs, AR. The clay contains 80% expandable portion and has both a 14.22 and 18.24 Å hydration state in addition to the 9.49 Å dehydrated state; ethylene glycol expands this material to 16.69 Å. The 060 reflection for all hydration states is between 1.50 and 1.51 Å indicating the material is dioctahedral. The “mean chemical formula” calculates as(Ca0.08 K0.02 Na0.03)0.13 (Al0.11 V0.90 Ti0.19 Fe0.64 Mg0.14)1.98 (Si3.79 Al0.21)4 O10 (OH)2·nH2O.

The aim of the present study was to examine effects of black liquor-montmorillonite (BL-Mnt) complexes on the mechanical and thermal properties of epichlorohydrin rubber. Considering the stability effect of lignin and the barrier property of clay minerals, a significant enhancement of thermo-oxidative aging properties of ECO/BL-Mnt composites was expected. Poly (epichlorohydrin-co-ethylene oxide) (ECO) composites filled with BL-Mnt complex were prepared by mechanical mixing on a two-roll mill. The ECO/BL-Mnt composites were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Both XRD and TEM data showed that the filler particles were well dispersed throughout the ECO/BL-Mnt composites. The tensile strength, elongation at break, and 100% modulus of the rubber composite were 14.0 MPa, 457%, and 3.9 MPa, respectively, at a 50% loading of BL-Mnt. The retention of tensile strength was 99% after thermal oxidative aging in an air-circulating oven for 72 h at 100°C. Evidence indicated that ECO/BL-Mnt composites with good mechanical properties and thermo-oxidative aging properties were obtained.

The state of iron in coal gangue minerals is an important factor in determining the potential for value-added utilization of this solid waste; this is especially true for the coal gangue coming from the Pingshuo open-pit mine in China. The objective of the present study was to characterize the petrological, mineralogical, and chemical states of Fe in the coal gangue from the Carboniferous Taiyuan Formation. Methods used included polarizing microscopy, X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive spectroscopy (SEM–EDS), X-ray fluorescence, micro-Fourier-transform infrared (micro-FTIR) spectroscopy, and Mössbauer spectroscopy. The coal gangues are mudstones, silty mudstones, and pelitic siltstones, which are composed primarily of kaolinite, quartz, feldspar, pyrite, illite, and magnesite. In coal gangue, the Fe was found to occur in ferruginous minerals, in crystal-lattice substitutions, or in a colloidal state. The ferruginous minerals in the coal gangue are pyrite and marcasite, and the pyrite morphologies are framboidal, euhedral octahedral crystals, subhedral granular crystals, and irregular crystals. The results of SEM–EDS and micro-FTIR confirmed that the lattice substitution of Fe in the coal gangue minerals occurred mainly in kaolinite, resulting in two types of kaolinite: iron-containing and iron-free kaolinite. The former may be transformed from volcanic biotite and the latter from volcanic feldspar. The Mössbauer spectra of kaolinite showed intense doublets with isomer shift and quadrupole splitting values consistent with tetrahedrally coordinated Fe3+ and ocahedrally coordinated Fe2+, suggesting the presence of two types of substitution sites: (1) Fe2+ replacing Al3+ in the octahedral sheet; and (2) Fe3+ replacing Si4+ in the tetrahedral sheet. This study has important theoretical significance for the high-value utilization of coal gangue.

Tracing interactions during burial-induced organic maturation and associated clay-material alteration is of prime importance for understanding both the individual and combined mineral and organic processes. In the present study the light elements B, Li, O, and H of a sample from oil-prone Eocene Kreyenhagen Shale from San Joaquin Basin (California) were examined. The natural burial-induced temperature increase was simulated by pyrolysis experiments at progressively increasing temperatures (270–365°C) and for varied durations (72–216 h) applied to the whole rock and its <2 μm fraction. The illite structure as well as the K-rich interlayers of the illite-smectite mixed layers were not affected by the pyrolysis experiments and the smectite-rich interlayers did not collapse, while the soluble minerals and the organic matter were altered. The distribution pattern of the rare-earth elements (REEs) from untreated whole rock and of its pyrolyzed equivalents are within analytical uncertainty, which confirms that the changes induced by pyrolysis experiments were minimal in the bulk sample. Conversely, the REEs from the <2 μm fractions were modified significantly, suggesting that the whole rocks and the <2 μm fractions may contain different types of organic materials. Also, only the carbonates, oxides, chlorides, and organic matter were affected together with the smectite-rich interlayers of the illite-smectite structure. Bitumen coating of the smectite interlayers probably increased the amount of B of organic origin in their sites. The δ11B and δ7Li of the successively expelled hydrocarbon phases changed with increasing pyrolysis temperatures, together with the B and Li contents of the hydrocarbon-related fluids. On the basis of the δ11B and δ7Li from pyrolyzed clay fractions, the B released successively was not isotopically homogeneous, probably depending on how the type of organic matter decomposed during the successive pyrolysis steps, and on which components were released. The δ11B of organic-B increased progressively from –2‰ at low experimental temperature up to +9‰ at the highest temperature. The calculated δ7Li that was released also increased relative to the value of the outcropping sample used as a reference, but it remained almost constant from –7‰ at 310°C for 72 h to –8‰ at 365°C for 216 h. The δ18O values of the <2 μm size fractions decreased significantly during pyrolysis above 300°C, but the δD changes were rather modest. The total organic carbon (TOC) remained statistically constant after pyrolysis to 300°C, as did the δ7Li values. The pyrolysis experiments in the present study suggest the presence of bitumen-coated smectite interlayers that could have been misidentified as dehydrated smectite in the literature. Together with abnormal illite K-Ar ages, the occurrence of such bitumen-coated illite-smectite interlayers occurring in source and reservoir rocks could indicate the timing of hydrocarbon maturation relative to illitization.

Biocompatible drug-delivery materials are important because they provide controlled release of biologically active agents to enhance the effectiveness of medical treatments. Montmorillonite (Mnt) has been utilized in drug-delivery systems for delayed-release application because it can safely encapsulate drug molecules via intercalation reactions. The objective of the present study was to evaluate the delivery characteristics of the drug ciprofloxacin (CIP) from a composite with Mnt (Mnt-CIP) in which the Mnt was first prepared by acid treatment and vibration ball milling. The surfaces of Mnt were modified by reacting the Mnt suspension in 1.0 M HCl acid and by dispersing the powder with a vibration ball mill, then the CIP drug was added at pH 4 and stirred. The goal was to improve the sustained-release performance of the CIP. This Mnt-CIP drug-release system was characterized by X-ray diffraction, X-ray fluorescence analysis, Fourier-transform infrared spectroscopy, surface area measurement using the Brunauer-Emmett-Teller (BET) method, and ultraviolet spectroscopy. The X-ray diffraction results confirmed the intercalation of CIP into the interlayer space of Mnt. The in vitro release properties of the intercalated CIP were investigated using a simulated phosphate-buffered saline solution (pH 7.4) at 36±0.5°C. The CIP drug exhibited a continued release for 3 h. Moreover, Mnt prepared by HCl acid treatment and dispersion in the vibration ball mill delayed the drug dissolution rate. In summary, the Mnt-CIP composite prepared in this study exhibited slow and sustained release characteristics, indicating that Mnt mined from the Gampo-40 mining area in Gyeongju can be used in various drug-delivery applications.

Np and Pu are two important actinides of concern for the safe long-term disposal of nuclear waste. Both actinides are, in addition, constituents of global nuclear fallout. Investigation of their environmental behavior requires ultra-sensitive analytical methods, but current methods for a concurrent determination in clay minerals are lacking. In the present study, a Pu isotope was investigated for use as a non-isotopic yield tracer for Np in extraction, purification, and mass spectrometric determination of Np and Pu isotopes in clay materials. Inductively coupled plasma mass spectrometry was used in this developmental study, but the method is intended for future ultra-trace analysis of global-fallout Np and Pu in clay-rich soil materials by the more sensitive accelerator mass spectrometry. Another field of application may be the investigation of diffusion patterns of actinides in compacted clay liners and potential host rocks for radioactive waste disposal. The analytical procedure includes the following steps: (1) extraction of Np and Pu from clay samples; (2) adjustment of Np and Pu to Np(IV) and Pu(III); (3) pre-concentration of Np and Pu by co-precipitation with iron hydroxide; (4) adjustment of Pu to Pu(IV); (5) extraction chromatographic separation of Pu and Np from iron and matrix elements; and (6) determination of Np and Pu by mass spectrometry. The analytical procedure was applied successfully to spiked montmorillonite and illite test portions of up to 1 g. High chemical yields near 90% were obtained for both Np and Pu. The suitability of Pu as a non-isotopic tracer for Np was indicated by Np/Pu chemical yield ratios close to unity. Accurate pH adjustment during the reductive co-precipitation and short processing times are vital to obtain high chemical yields and Np/Pu yield ratios close to unity.

Hydrocalumite (HC) is a type of synthetic layered double hydroxide (LDH) that has many important industrial uses and is commonly synthesized by a co-precipitation method in a water:ethanol (2:3) mixture; however, atmospheric carbon dioxide interferes with the synthesis by decreasing the solubility of other gases in the reaction medium. The aim of the present study was to vary the temperature and aging time used in the coprecipitation method in order to mitigate the adverse effects of carbon dioxide. The water/ethanol mixture (2:3) was able to prevent atmospheric carbon dioxide contamination of the sample, as it decreased the solubility of the gas in the reaction mixture. Aging time (9–36 h) and temperature (35–95°C) were varied to modify the hydrocalumite structure, textural properties, thermal stability, and basicity. The characterization of the samples was performed using X-ray diffraction (XRD), X-ray fluorescence (XRF), Fourier-transform infrared spectroscopy (FTIR), nitrogen physisorption, thermogravimetric analysis (TGA), and CO2 temperature-programmed desorption (TPD-CO2) techniques. The aging time of 9 h and temperature of 95°C provided the most crystalline sample with the largest mean crystallite size (49 nm). The variation of the synthesis conditions also provided changes in the surface area (6.5–20.2 m2 g–1), pore diameter (116–148 Å), and pore volume (0.0147–0.0499 cm3 g–1). The temperature ranges for thermal decomposition of structural water and carbonate varied among the samples, indicating different thermal stabilities. The basicity (basic sites quantified by TPD-CO2) was also affected by the change in aging conditions; the sample aged for 9 h at 65°C presented the greatest basicity (1557 μmol g–1), whereas that aged for 36 h at 35°C had the least basicity (337 μmol g–1).

The recent interest in the determination of the phase diagrams for many systems involving water as one component has been in those systems which are of greatest importance to clay mineralogy.

The importance of both published and more recent work on synthesis of the clay is demonstrated in the ability to prepare chemically pure, mineralogically homogeneous kaolinites, montmorillonites, micas, and chlorites. The stability and identification of the clay minerals are discussed in relation to some of the major problems of clay mineralogy. Some of the chief objections to data obtained by the usual hydrothermal techniques are treated at length.

Samples of altered volcanic materials, interbedded with dominantly carbonate sediments, were collected from Ordovician, Silurian, and Devonian strata in Michigan, Illinois, Kentucky, Pennsylvania, Virginia, and Alabama. These altered volcanics, originally called metabentonite and more recently K-bentonite, occur in thin seams commonly only a few inches thick and are generally believed to be altered Paleozoic volcanic ash falls because they contain typical igneous minerals in the heavy suite and retain textures and structures characteristic of ash deposits.

Petrographic, differential thermal, and X-ray analyses were made of these samples to determine the clay mineralogy. Mixed-layer illite-montmorillonite occurs in the majority of samples. Illite is present in all samples and chlorite occurs in a few samples. This is in general accord with findings of previous studies. The mixed-layer clay is believed to have been deposited as montmorillonite in a marine environment and subsequently altered largely to illite through fixation of K in the interlayer position.

K-bentonites from Michigan and Illinois contain a constituent which has a 7.6 Å d-spacing. It is suggested that this material may be of regional significance because its occurrence was confined to the Upper Mississippi Valley K-bentonites in samples of this study.

A study has been made of the interaction of azobenzene vapor with a series of cation-exchanged montmorillonites. Cu2+- and Ag+-clays give basal spacings ≥ 20Å. The azobenzene retains its trans conformation in the clay and can be extracted with ether. If the intercalate is heated above 120°C then there is catalytic decomposition leaving a black product. Infrared spectra of an extract from this product suggests that it might be made up of a mixture of amines. A photo-electron spectroscopic study shows that the nitrogen is in two distinct chemical environments both in the initial and in the blackened intercalates. The C:N ratio remains at 6:1 throughout.

Catalysts are very important in the use of cellulose, the main component of biomass, as a raw material for the large-scale production of liquid fuels and chemicals. 5-Hydroxymethylfurfural (HMF) is an extremely important intermediate in the fine chemical industry. HMF can be synthesized by acid-catalyzed dehydration of fructose, glucose, cellulose, or sucrose. The conversion of cellulose to HMF is challenging due to its chemical structure. The objective of the present study was to devise a more facile synthesis method using transition metal-doped montmorillonite catalysts (10Cr-Mnt, 10Cu-Mnt, 10Fe-Mnt, and 10Zn-Mnt) by wet impregnation. Samples were characterized by X-ray powder diffraction, specific surface area, and NH3-TPD analyses. The synthesized catalysts were used for the conversion of cellulose to 5-HMF in an aqueous medium. Among the metals studied, Cr showed the greatest catalytic activity. With the use of this catalyst, efficient conversion of cellulose to 5-HMF was achieved, affording a conversion yield of 93.47% and 5-HMF yield of 9.07% within 6 h at 200°C. The study described here could be useful for the efficient conversion of cellulose into 5-HMF, as well as into other biomass-derived chemicals.

At the 4th International Soil Science Congress held in Amsterdam (1950) a special meeting discussed the nomenclature of clay minerals and suggested “hydrous mica” as a general term for those clay minerals that are neither well crystallised micas nor pure expanding minerals.

In the past various names have been used for the hydrous micas. As early as 1912, Galpin, and later, in 1920, Bayley, introduced the terms “hydro-mica” and “hydrous mica” respectively, to designate a micaceous clay mineral. Since then, reports have been made of the presence in soils of a potash-bearing clay mineral (Wherry et al., 1929), and in clays of a mica-like clay mineral (glimmerartige Tonmineralien) (Endell et al., 1935), and a sericite-like mineral (Grim, 1935). In 1937 Grim et al., for the first time proposed the term “illite” as a “general term for the clay mineral constitutents of argillaceous sediments belonging to the mica group.” Other names include bravaisite (Ross and Hendricks) and sarospatite (Maegdefrau and Hofmann, 1937), but the validity of these as specific minerals is questionable since they have been found to exist as mixtures of hydrous micas and montmorillonoids (Bradley, 1945; Brindley, 1951).