The hydrogen isotopic composition (δ2H) of authigenic clay minerals has been used extensively in paleoclimate studies. The separation of clay minerals from sediments/soils, using various chemicals, is a prerequisite for isotope ratio measurements, where carbonate, Fe-(oxyhydr)oxides, and organic matter are removed successively from the sediments for a greater clay yield. The commonly adopted organic matter-removal method using hydrogen peroxide (H2O2) is thought to either alter directly the pristine δ2H values of the smectite clay minerals or to introduce organic hydrogen-bearing impurities through the ineffective removal of organic matter. The objective of the present study was to test whether H2O2 treatment can alter the δ2H values of kaolinite (Kln) by comparing two organic matter-removal methods, namely, H2O2 and disodium peroxodisulfate (Na2S2O8) combined with a neutral buffer. In doing so, kaolinite-rich, old (~56 Ma) sediment samples and pure kaolinite internal laboratory reference materials were used to understand the effectiveness and suitability of the above-mentioned methods in clay-sample preparation for δ2H measurements. The δ2H values of the H2O2-treated aliquots show smaller δ2H values than those for the Na2S2O8-treated aliquots. Estimated ambient water δ18O values (−4‰) from the Na2S2O8-treated aliquots agreed well with the bio-phosphate (fish vertebrae) based environmental water δ18O estimation (−3.3‰). The present study indicated, therefore, that δ2H values obtained after Na2S2O8 treatment are likely to be more realistic for paleoclimate reconstruction.

A wick structure is the core part of a heat pipe that produces capillaries to move liquid from a condenser to an evaporator. The purpose of the current study was to develop a wick structure from zeolite and kaolin using various sintering methods. Due to significant porosity and water-adsorption properties, zeolite and kaolin can produce a large capillary force inside the heat pipe. A porous wick specimen is developed from pure zeolite together with a mixture of zeolite and kaolin by using pressureless (loosely packed) and conventional pressurized sintering for thermosiphon heat-pipe applications. Major properties such as porosity, water adsorption, and permeability were noted to be better under pressureless sintering compared to pressurized sintering. Significant and uneven shrinkage in both radial and linear directions is a major problem in loosely packed sintering of pure zeolite. However, the addition of kaolin helps to overcome the problem of porosity and shrinkage in pure zeolite; but the permeability and strength of the wick structure are reduced with the addition of kaolin. A general trend is that increasing porosity causes increasing permeability. Due to grain size and compaction, however, permeability is reduced with the addition of kaolin. Based on the experimental results for porosity and permeability, the wick structure formed from zeolite with 5–10% of kaolin has better thermal properties for heat-pipe applications.

The crystal structure of cronstedtite-2H2 was refined in a hexagonal cell, space group P63, Z = 2, using two acicular crystals from Wheal Maudlin, Cornwall, England, and from Pribram, Czech Republic. The Wheal Maudlin sample has the chemical composition $\left({\text{Fe}}_{2.291}^{2+}{\text{Fe}}_{0.709}^{3+}\right)\left({\text{Si}}_{1.298}{\text{Fe}}_{0.707}^{3+}{\text{Al}}_{0.004}\right){\text{O}}_5{\left(\text{OH}\right)}_4$ and the Příbram sample has the composition $\left({\text{Fe}}_{2.269}^{2+}{\text{Fe}}_{0.731}^{3+}\right)\left({\text{Si}}_{1.271}{\text{Fe}}_{0.724}^{3+}{\text{Al}}_{0.005}\right){\text{O}}_5{\left(\text{OH}\right)}_4$. The results of refinements are as follows: a = 5.500(1), c = 14.163(2) Å, V = 371.08(8) Å3, R = 3.83%, from 381 independent reflections, and a = 5.4927(1), c = 14.1481(2) Å, V = 369.70(4) Å3, R = 4.77%, from 1088 independent reflections for the Wheal Maudlin and Příbram samples, respectively. The best Fovs.Fc agreement was achieved when the structure was interpreted as merohedral twin; several possible twinning laws are discussed. The cronstedtite layer consists of one tetrahedral sheet and one octahedral sheet. There is one octahedral (M1) position, occupied by Fe only, and two tetrahedral (T1, T2) positions in the structure. Refinement of occupancy of tetrahedral sites led to values Si:Fe = 0.45:0.55(1) (Wheal Maudlin) and 0.432:0.568(8) (Příbram) in T1, and Si: Fe = 0.99:0.01(1) (Wheal Maudlin) and 0.888:0.112(7) (Příbram) in 72. Whereas the size of T1 is reasonable (average dT1-O = 1.693 Å (Wheal Maudlin), 1.691 Å (Příbram)), T2 is unusually large: (dT2-O= 1.740 Å (Wheal Maudlin), 1.737 Å (Příbram)) with respect to the small or almost zero Fe content. As an explanation, an alternative structure model comprising a certain amount of vacancies in T2 is presented. The tetrahedral rotation angle α is highly positive (+12.1° and +12.5° for the Wheal Maudlin and Příbram samples, respectively), and the layer belongs to the Franzini type A. Distortion parameters of octahedra and tetrahedra are given for both samples. One hydrogen atom engaged in the hydrogen bond was located in the Wheal Maudlin sample.

The ability of hydrotalcites to retain anionic wastes was studied. In particular, Cr(VI)-adsorbed hydrotalcites were heated to immobilize Cr(VI) in the solid sample. When the heating temperature increased up to 500°C, the lamellar structure of hydrotalcite was lost. At high temperatures (1200°C), the solids were recrystallized in the form of a spinel. Lixiviation with 1 N and 5 N NaCl solutions were utilized to simulate the effect of sea water and of concentrated NaCl solutions in salt mines on the immobilization of Cr. Radiation damage on the solid containing the immobilized Cr was studied by γ-irradiating with a 60Co source at 1000 and 6000 kGy. The Cr-containing samples heated at 1200°C, whether irradiated or not, safely immobilized Cr in the hydrotalcite mainly in the form of MgCr2O4 spinel. Irradiation of hydrotalcites revealed two different effects: (1) samples heated up to 1200°C evolved as a solid in which chromium was retained more firmly than in the non-irradiated material, irradiation enhancing the spinel formation; (2) the structure of samples heated at 1200°C developed a preferential crystallite orientation rather than a purely random one or new location of chromium ions, this effect did not affect Cr immobilization in the solid. Chromium lixiviation with 5 N NaCl solution was always less than the corresponding value with 1 N NaCl solution, probably due to the poor mobility of Cl− ions in the highly concentrated NaCl solution.

The objective of this study was to explore the geological origin of glauconite, which is believed to precipitate and mature very slowly (~1 Myr) in neritic environments (shallow water, oceanic coastal zones, at water depths of 100–200 m) with very low sedimentation rates. A series of simulation experiments was designed and carried out in sealed tubes placed in an oven and heated to a constant temperature of 50°C (±2°C) for 60 or 150 d. The parent materials used for these experiments were two low-Fe montmorillonites with different crystallinities. The montmorillonites were introduced to solutions with concentrations of 0.02–0.1 mol/L Fe3+ and 0.05–0.2 mol/L K+ with various values of pH and Eh. The products were analyzed using X-ray powder diffraction (XRD), Fourier-transform infrared (FTIR) spectrometry, electron spin resonance (ESR) spectrometry, scanning electron microscopy (SEM), and Mössbauer spectroscopy. The morphological changes from parent material to product were observed under SEM, which revealed the formation of a flaky mineral (e.g. a product formed in the interstitial spaces between montmorillonite crystals). The formation of a flaky mineral indicates that the product is a layer silicate. Qualitative analysis of XRD patterns revealed that the main product phase was a mica group mineral and the d060 value was consistent with the presence of glauconite (0.152 nm) and/or Fe-illite (0.150 nm). A glauconite and Fe-illite mineral assemblage formed in a weakly acidic solution, while Fe-illite, mixed-layer Fe-illite, and montmorillonite formed in neutral and alkaline solutions. Stretching vibrations of Fe(III)Fe(III)OH-AlFe(II)OH and/or MgFe(III)OH were observed in FTIR spectra (3550–3562 cm−1) of the products formed in acidic solutions, which along with the g = 1.978 ESR signal indicated that Fe(III) entered octahedral positions in the tetrahedral/octahedral/tetrahedral layer (TOT) platelets. The AlFe(II)OH-MgFe(III)OH (3550–3562 cm−1) and AlFe(III)OH (870 cm−1) vibrations were only observed in products formed in neutral and alkaline solutions. Analysis of the Mössbauer spectra showed that Fe(III) substituted for Al and Mg in the cis octahedral sites of montmorillonite. The simulation experiments demonstrated that the pH and redox conditions (Eh) of the environment controlled the nature of the product mineral species. Results of the present study revealed that glauconitization and illitization occurred under different conditions, where glauconitization preferentially occurred in an acidic environment and illitization preferentially occurred in a nearly neutral to alkaline environment.

X-ray diffraction shows that ordered interlayer structures form when high-charged Llano vermiculite is reacted with HDTMA-Br or HDTMA-acetate, but the structures differ from those given by low-charged vermiculites. The differences arise in two ways; firstly when both HDTMA+ cations and HDTMA-Br (or -acetate) ion pairs are present as interlayer guest species, a superstructure forms which is less commensurate with the host structure of high-charge vermiculite than it is for lower-charged material. Secondly, although a commensurate 3a × b interlayer superstructure forms when HDTMA+ cations are the only interlayer guests, an increasing number of charge-balancing cations must be accommodated as the layer charge increases. This results in some structural disorder which is only observed in the diffraction pattern of HDTMA+-intercalated, high-charge vermiculite. Organic ion pairs tend to order along widely spaced rows corresponding to the intersections of two sets of scattering planes. For the acetate form, one set of planes has spacings of 3.52 Å, but for the bromide form the value is 3.67 Å. Scattering planes in the second set have spacings of 4.02 Å, independently of counter-anion size. These two sets of planes diverge from one another by ∼10°. Ordering is more apparent in the presence of acetate anions than it is for the smaller Br− anions. In the high-charged intercalates, from which organic ion pairs have been removed, HDTMA+ cations occupy positions on a centered two-dimensional superlattice and also randomly, some interstitial positions as necessitated by layer charge.

Diagenesis of the Holocene-Pleistocene volcanogenic sediments of the Mexican Basin produced, in strata of gravel and sand, 1H2O- and 2H2O-smectite, kaolinite, R3-2H2O-smectite (0.75)-kaolinite, R1-2H2O-smectite (0.75)-kaolinite, R3-kaolinite (0.75)-2H2O-smectite and R1-1H2O-smectite (0.75)-kaolinite. Smectite platelets were formed from volcanic glass by loss of Si4+. Partially-formed platelets have Si4+ between 4.55−4.10 a.p.f.u., Mg+Mn and the interlayer charge are relatively uniform while VIAl+Fe3++Ti varies between 0.98 and 1.63 a.p.f.u. Almost fully transformed platelets have Si4+ of 4.08−4.04 a.p.f.u.; Mg+Mn and the interlayer charge decrease proportionally to increasing VIAl+Fe3++Ti. Smectite-kaolinite mixed layers have octahedral occupancies of 2.01–2.15 a.p.f.u., IVAl3+ 0.09–0.55 a.p.f.u. and interlayer charges about half that of smectite; structural formulae corresponding to smectite (0.75–0.80)-kaolinite indicate octahedral occupancy of 2.50 a.p.f.u., tetrahedral replacement 0–0.31 a.p.f.u., and interlayer charge 0.24–0.51 equivalents, some indicating interstratifications of beidellite. Kaolinite is presumed to have formed from K-feldspar; smectite-kaolinite interstratifications sustain the transformation of kaolinite to smectite in an increasingly siliceous high-cation environment. In the mudstones of low-hydraulic conductivity and practically stagnant alkaline fluids, glass was transformed to 2H2O-smectite lamellae of IVAl between 0 and 0.47 a.p.f.u., octahedral occupancy 1.70–2.00 a.p.f.u. and interlayer charge of 0.23–1.21 equivalents, some corresponding to beidellite. The interlayer charge increases with IVAl and decreasing occupancy of the octahedral sheet; the abundance of Mg+Mn is inverse to that of VIAl+Fe3++Ti.

Clay suspensions containing 1H2O- and 2H2O-smectite, kaolinite and R3-2H2O-smectite (0.75)-kaolinite lead to low-energy edge-to-edge particle associations, non-Newtonian pseudoplastic behavior, and maximum apparent viscosity of 180 Pa s at 0.008 s−1 followed by rapid descent. Clay fractions with slightly larger 2H2O-smectite contents and smaller kaolinite contents reach maximum viscosity of 3611 Pa s at a shear rate of 0.0018 s−1 and of 3300 Pa s at 0.0024 s−1. They denote two high-energy face-to-face particle associations, followed by slow descent of the apparent viscosity under viscous flow. Suspensions change from elastic to viscous behavior at shear stresses of 1.03 and 5.91 Pa, respectively. Clay suspension vibrated at a frequency of 1 Hz develops a shear storage dynamic modulus greater than the shear dynamic loss modulus or the energy is preferentially stored, whereas at 5 Hz more energy is dissipated than stored.

As a common mineral phase on Earth and Martian regolith, natural rutile was reported as a potential candidate for use as a Fenton catalyst in this study. The influences of Fe and V in various chemical states on the generation of reactive oxygen species (ROSs) and the catalytic activity of rutile were examined. A series of rutile samples with various surface and bulk states of Fe and V were obtained initially by hydrogen annealing of natural rutile at ~773–1173 K. X-ray diffraction, electron paramagnetic resonance spectra, and X-ray photoelectron spectroscopy demonstrated that the atomic fractions of Fe(III) and V(V) decreased sharply with increasing temperature, along with the accumulation of surface Fe(II) and bulk V(III). All as-prepared materials showed enhanced Fenton degradation efficiency on methylene blue (MB) compared with P25-TiO2, and the treated samples exhibited up to 3.5-fold improvement in efficiency at pH 3 compared to the untreated sample. The improved efficiency was attributed mainly to Fenton catalysis involving Fe(II) and V(III). The dissolved Fe2+ played a crucial role in the homogeneous Fenton reaction, while the bound V(III) favored adsorption primarily and may have facilitated heterogeneous Fenton reaction and the regeneration of Fe2+. The pH regulated the reaction mechanism among homogeneous (pH = 3) and heterogeneous (pH = 3.7) Fenton catalysis and physical adsorption (pH = 5, 6). The aim of the present study was to improve the understanding of the potential role of natural rutile with advanced oxidation functions in Earth systems and even on Mars, which also provide an inspiration for screening natural rutile and any other similar, Earth-abundant, low-cost minerals for environmental application.

As a photocatalyst with good prospects, TiO2 has the shortcomings of easy agglomeration and no catalytic performance under visible light. The purpose of the present study was to help solve these problems by employing muscovite as a carrier for N-doped TiO2 in a nanocomposite. The nanocomposites were prepared by a liquid precipitation-grinding method using muscovite as the matrix and urea as the nitrogen source. The crystal structures, chemical bonding, and micromorphology of the nanocomposites were analyzed by X-ray diffraction, infrared absorption spectrometry, and field emission scanning electron microscopy, respectively. Visible and ultraviolet (UV-Vis) light absorption of the nanocomposites was analyzed by solid ultraviolet diffuse reflectance spectroscopy. The photocatalytic effect of the nanocomposites was studied based on the degradation of rhodamine B (RhB) solution. The photocatalytic degradation product of RhB was detected by high-performance liquid chromatography-mass spectrometry, revealing that N-doping inhibits the growth of TiO2 nanoparticles. The photocatalytic performance of N-TiO2/muscovite composite nanomaterials decreased with increasing heat-treatment temperature. N-doped TiO2/muscovite nanocomposites that were heated at 400°C showed the best photocatalytic performance under visible-light illumination with an RhB degradation of 97%.

The number of studies of controlled drug-release systems is growing constantly. Bionanocomposite materials which can be prepared from the combination of biopolymers with inorganic solids such as clay minerals offer interesting alternatives for use as drug-delivery systems. In the present study, new bionanocomposite drug-release systems were prepared from the intercalation of the antibiotic drug ciprofloxacin into montmorillonite using an ion-exchange reaction. In order to prepare more stable systems for oral ciprofloxacin release, this ciprofloxacin-clay intercalation compound was incorporated into i-carrageenan-gelatin biopolymer blend to produce bionanocomposite materials. Bionanocomposites of two distinct i-carrageenan and gelatin mass ratios were conformed as beads through an ionic gelification reaction with Ca2+ ions, and dried by freeze-drying where liquid nitrogen or conventional freezing was adopted in the freezing step. The resulting ciprofloxacin-clay hybrid was characterized by X-ray diffraction (XRD) analysis, Fourier-transform infrared (FTIR) spectroscopy, solid state 13C Nuclear Magnetic Resonance (NMR), thermal analysis, and scanning electron microscopy (SEM). The montmorillonite-ciprofloxacin hybrid incorporated into the bionanocomposite beads was evaluated by in vitro release studies which showed a significant difference in the release profiles in the aqueous medium used to simulate the gastrointestinal tract, depending on the blend composition and the freezing method employed in the preparation of the beads. The results point to bionanocomposite systems based on ciprofloxacin-clay hybrids and biopolymers that may be used as devices in the biomedical area.

The conventional method of zeolite synthesis involves an expensive hydrothermal step whereby a mixture of a metakaolinite, sodium hydroxide, and water is preactivated by thermal treatment between 400°C and 1000°C. The objective of the current study was to determine whether Jordanian kaolinite could be converted to zeolite materials without thermal pre-activation. The alkaline hydrothermal transformation of kaolinite into hydroxysodalite (HS) was achieved, then followed by a reaction with citric acid and solid sodium hydroxide to obtain Zeolite A, or by adding solid Na2SiO3 to prepare zeolite X. These materials were tested for their ability to serve as removal agents for Basic Blue 41 (BB-41) dye from artificially contaminated water, at concentrations ranging from 25 to 1000 mg/L. The maximum removal capacities were estimated using the Langmuir model, with a value of 39 mg/g for hydroxysodalite. Zeolite-X achieved the lowest value (19 mg/g). The feasibility of BB-41 removal was deduced from the Freundlich model for the zeolites studied. The reported low-cost method is proposed as an alternative way to reduce the cost of synthesizing zeolite, and the materials were shown to be potential candidates for the removal of BB-41 dye.

This article examines a cohort of post–World War II temperance activists who attempted to legally curtail the circulation of advertisements for liquor, wine, and beer. These activists, who were primarily associated with Protestant church and lay organizations, pressured lawmakers to hold multiple Senate hearings for a series of bills that would prevent any media bearing enticements to purchase alcoholic beverages from moving across state lines. The proposed legislation not only threatened the growth of alcoholic beverage industries, it also took aim at the media makers and advertising firms that endorsed and benefited from the sale of liquor, wine, and beer. This article explores the under-studied archives of the mid-century temperance movement—including the transcripts of their Senate hearings, the minutes of their organizing meetings, the mail they sent to media makers, and their published pamphlets—to illuminate their antagonistic approach to the ballooning world of mass media. I argue that efforts to censure liquor advertising were efforts to discipline and censure the communications industry elites whose products increasingly defined daily life. While many histories describe the Christian actors who took mass media by storm, this article highlights those who situated themselves as a moral check on the perceived excesses of mid-century mass culture.

Beginning in 1867 with the invention of the miniature (or “hobby”) press, young people in the United States began to publish their own amateur newspapers. Within the pages of those publications, adolescents included news articles, editorials, short stories, serialized fiction, poetry, and jokes. The collective result of their literary efforts was referred to as Amateurdom, or “the ’Dom” for short. Included in this teaching supplement are several representative short stories and editorials published by adolescents during the 1870s and 1880s. After reading the primary source material, students might be prompted to address some the questions for discussion included below.

In Christian tradition, Paul is the apostle to the nations. However, his portrayal in the Book of Acts is more nuanced. For a longer period, Paul's ministry is limited to Jews. Only from Acts 13 onwards does Paul slowly emerge as ministering to non-Jews. Yet even then, Paul remains foremost an emissary to diaspora Judaism. In its apology for Paul and his disputed way of including non-Jews into the people of God, Acts emphasises that Paul did so without diminishing the priority of Israel, as a staunch proponent of Jewish monotheism and in a way that took full account of the precarious situation of diaspora Judaism.

The mechanism for the kaolinization of smectite is extremely complex. The purpose of this study was to explore this mechanism by providing more microscopic information about kaolinite-smectite (K-S) intermediate phases. Crystal-chemical changes were investigated and integrated in a model of the transformation mechanism. Eight K-S samples from three localities, derived from volcanic ash beds, were studied using transmission and analytical electron microscopy (TEM, AEM) and high-resolution TEM (HRTEM). The study completes a previous investigation, using several analytical techniques. The samples cover the range of K-S composition available from the previously studied sample set. Analysis by TEM indicated the preservation of particle morphology throughout the process. Most K-S particles had anhedral, smectite-like morphology, and only the most kaolinitic specimen revealed the coexistence of anhedral and euhedral, hexagonal particles. Analytical electron microscopy showed large chemical variations within samples, corresponding to various degrees of smectite kaolinization. Comparison of chemical results (Si/Al) and d060 values (proxy for octahedral composition) with the extent of kaolinization from thermogravimetry (TG) indicates that chemical changes in the octahedral sheet occur mainly when the proportion of kaolinite is 40–70%. The results above are consistent with kaolinization occurring via layer-by-layer transformation through the progressive loss of individual tetrahedral sheets in smectite layers and subsequent chemical changes in the octahedral sheet. Such a mechanism would produce the results observed in this study: (1) most particles preserve their original morphology; (2) significant variation in terms of the extent of transformation of particles within samples, and (3) formation of crystal structures intermediate between those of smectite and kaolinite, with parts of the tetrahedral sheets missing (kaolinite-like patches). Such structures become least stable at kaolinite ∼50%, when the perimeter of the kaolinite-like patches is largest and chemical changes in the octahedral sheet can occur more easily. Kaolinite layers could not be resolved by HRTEM in most cases and showed lattice fringes corresponding to superstructures. A model was established to quantify kaolinite and smectite layers in the HRTEM images with results which matched TG-derived values.