Toxic metal contamination of waste waters can be mitigated by metal adsorption to clay and zeolitic minerals, but in developing countries such environmental remediation can be cost prohibitive if these minerals are not readily available. Because of its abundance, low cost, and excellent selectivity for several toxic metal ions, clinoptilolite from the Zlatokop deposit in Serbia was investigated for its ability to remove copper ions from aqueous solutions and serve as an effective local resource for this purpose. The sorption capacity of the clinoptilolite at 298 K varied from 8.3 mg Cu g−1 (for C0 = 100 mg Cu dm−3) to 16.8 mg Cu g−1 (for C0 = 400 mg Cu dm−3). The sorption data were best described by the Freundlich isotherm and the sorption kinetics followed the pseudo-second-order model. Intra-particle diffusion of Cu2+ was present but it is not the rate-limiting step. The sorption of Cu2+ on the clinoptilolite occurred spontaneously, the free energy change decreasing with temperature. The sorption was endothermic and was accompanied by an increase in entropy. Dehydration of the Cu-loaded clinoptilolite at 540°C led to the formation of nanocrystalline Cu(I) oxide particles with an average size of ~2 nm, suggesting possible novel applications for the Cu-loaded clinoptilolite.

Aluminum substitution is a common phenomenon in environmental iron oxides and oxyhydroxides, affecting the color, magnetic character, surface features, etc. Several methods for preparing Al-substituted iron oxyhydroxides can be found in the literature, resulting in samples with particular properties. In the present study, the synthesis of aluminum-substituted goethites, AlxFe1-xOOH with 0 ⩽ x ⩽ 0.15, by homogeneous precipitation and the transformation to aluminum-substituted hematites, (AlxFe1-x)O3, are presented. The goethite samples were produced at 90°C from solutions of urea and iron and aluminum nitrates in the presence of ammonium sulfate (GU series). Although attempts were made to incorporate up to 33 mole% of Al into the goethite, only ~15 mole% was found to be within the structure, due to the final pH, ~7, of the synthesis. Another feature of these goethites was a lateral alignment of the tabular particles. By heating batches of the GU samples at 400°C and 800°C, two series of Al-hematites were obtained, denoted here as the HX400 and HX800 samples, respectively. X-ray diffraction, thermal analysis, Karl-Fischer titration, transmission electron microscopy, and Mössbauer spectroscopy were used to characterize the samples. The X-ray patterns showed the samples to be pure iron phases, with particle sizes of ~10 nm for the GU and HX400 samples, and of ~70 nm for the HX800 samples. An inversion in the intensities of the (104) and (110) diffraction peaks of hematite was observed to be dependent on the aluminum substitution and was explained by small particle sizes, shape anisotropy, and the presence of nanopores. The cell parameters of both GU and HX samples showed a small decrease with increasing aluminum substitution up to x ≈ 0.15. The amount of adsorbed sulfate, presumably as an aluminum hydroxy sulfate gel, increased with aluminum substitution in all GU and HX samples, reaching a maximum of ~6.5 wt.% for the highest substitution. Heating at 100°C did not remove all of the adsorbed water, and significantly higher temperatures were required to achieve complete removal. Mossbauer spectra at 295 K and 80 K are typical for small-particle goethite and hematite, and revealed that Al-for-Fe substitution in all samples seems to be limited to ~15 mol.%.

The effects of pH and ionic strength on the rheological behavior of aqueous suspensions of both crude and purified Wyoming bentonite and natural interstratified illite-smectite from Tunisia were investigated. Flow tests were performed on the four clay suspensions at a 10% clay concentration at different pH values. They showed that the rheological properties were highly sensitive to pH and the nature of the clay. The evolution of the yield stress as a function of pH is characterized by the presence of maxima and minima attributed to changes in the mode of association of the particles. The effect of pH on the behavior of clay suspended in NaCl solutions was also studied. The results show that the presence of NaCl has very little effect on the pH and yield stress values of the four materials.

Iron-bearing K-dioctahedral 1M and 1Md micas are abundant in diverse geological environments and vary in composition from illite to celadonite through Fe-illite, Al-glauconite, and glauconite. The chemistry and structural features of these micas are complex and heterogeneous, reliable diagnostic criteria are lacking, and the conventional mineralogical nomenclature is ambiguous, which complicate the identification of these mica varieties. The objectives of the present study were to reveal the structural and crystal-chemical variability in Fe-bearing, K-dioctahedral 1M micas and to define composition ranges and identification criteria for the mica varieties in the series. A collection of samples of various compositions was studied using X-ray diffraction (XRD) and Fourier-transform infrared (FTIR) spectroscopy. Analysis of the relationships between unit-cell parameters and cation composition showed that the series included four groups, namely, Fe-bearing illites, Al-glauconites, glauconites, and celadonites and each group was characterized by a specific combination of unit-cell parameters and variation ranges. The illite group contained two distinct subgroups; Fe-bearing, Mg-rich illites and Feillites; which differ in the range of cation compositions and in FTIR characteristics. The boundary between Fe-illites and Al-glauconites occurs at a unit cell b value of ~9.05 Å and at ratios of octahedral Al to total trivalent octahedral cations that range between 0.60 and 0.65. The partially overlapping cation composition and cell parameter ranges may complicate the distinction between Al-glauconites and glauconites, which can still be unambiguously differentiated using FTIR data. The dramatically different XRD and FTIR characteristics confirmed that glauconite and celadonite should be treated as separate mineral species. The distinctive features of celadonite are relatively low csinβ values and reduced |ccosβ/a| values combined with b parameters lower than glauconites, but similar to Fe-illites. Celadonites also have distinct and sharp FTIR absorption bands at specific positions in the Si-O and OH stretching regions.

CaMnt is much less important than NaMnt due to its limited commercial applications. The time-dependent property of NaMnt gel has been studied extensively as it is exploited in many applications such as drilling mud and viscosity-modifier applications. In contrast, the time-dependent property of CaMnt suspension and the factors affecting it are largely unknown. The speciation of Ca2+ ions is one such factor to be evaluated. In the current study, pH and solids concentration were examined and then used to validate a recent theory on clay gel time dependency. The results supported the theory that a strong electrostatic double layer (EDL) repulsion in the 3-D network is needed to reorganize the structure and drive it toward the state of minimum free energy. The 12 wt.% CaMnt (STx-1b) gel displayed time-dependent behavior at pH 5 but not at its natural pH of 8.4. At pH 5, the interlayer Ca2+ ions became fully hydrated and desorbed from the platelet surface. This enhanced the EDL repulsion between the platelets. At pH >6.5, the positively charged hydrolysis product Ca(OH)+ began to form and was adsorbed, partially neutralizing the permanent layer charge and weakening the repulsion. However, at 19.4 wt.% solids, the gel displayed pronounced time-dependent behavior despite the high natural pH of 8. The platelets were much closer together, allowing the EDL force to operate and effect structural reorganization. The microstructure of these CaMnt gels showed high platelet concentrations interacting to form a relatively open structure. The microstructure of a kaolin (KGa-2) suspension which showed no time-dependent behavior even after 1 day of ageing revealed the importance of particle morphology and layer charge on time dependency. Its 3-D structure was formed by relatively thick, layered platelets with a low layer charge.

Cronstedtite from Lostwithiel, Cornwall, England, in which two polytypic groups (A and C) are present within the same crystal, has been investigated using various techniques to reveal the distribution of the two groups and the relationship between polytypic structure and chemical composition. X-ray precession photographs from cleaved fragments of pyramidal crystals revealed the variable proportions of the two groups from the top to the base. Near the top, the crystal consists entirely of group C, with 1T as the dominant polytype. Near the base, both groups A and C are present. Back-scattered electron images from cross-sections parallel to the pyramidal axis showed mosaic contrast near the base, suggesting that two compositionally-different domains of several tens of microns in size are present, whereas the contrast was uniform near the top. Electron microprobe chemical analysis indicated the compositions $\left({\text{Fe}}_{2.31}^{2+}{\text{Fe}}_{0.69}^{3+}\right)\left({\text{Si}}_{1.31}{\text{Fe}}_{0.69}^{3+}\right){\text{O}}_5{\left(\text{OH}\right)}_4$ and $\left({\text{Fe}}_{2.16}^{2+}{\text{Fe}}_{0.84}^{3+}\right)\left({\text{Si}}_{1.16}{\text{Fe}}_{0.84}^{3+}\right){\text{O}}_5{\left(\text{OH}\right)}_4$. Electron back-scattered patterns (EBSPs) confirmed that the domain with Si-rich composition belongs to group C and that with Si-poor composition to group A. This is the first evidence that specific chemical compositions are related to the polytypic structures in cronstedtite. Transmission electron microscopy revealed that intergrowth of groups A and C at the monolayer level is also present as stacking disorder in both domains near the base, whereas such intergrowth was not observed in the region near the top.

The normal prograde diagenetic and low-grade metamorphic sequence of dioctahedral clay minerals including illite-rich I-S and illite, as observed by TEM, proceeds from a partially disordered 1Md stacking sequence to 2M1; i.e. 1M does not normally occur as an intermediate polytype. Examples of 1M illite stacking sequences have been studied, however, from the Golden Cross gold deposit, New Zealand, the Broadlands-Ohaaki geothermal system, New Zealand, the Potsdam Sandstone, New York, and the Silverton Caldera, Colorado. Specific clay-mineral packets identified by TEM techniques as 1M illite were found to have anomalously high Mg contents. The Broadlands illite provides the most definitive data, as separate packets of 1M and 2M1 illite coexist. Average compositions for 1M and 2M1 illite are (K1.66Ca0.04)Σ1.70(Al3.32Fe0.31Mg0.57Mn0.06)Σ4.26(Si6.43Al1.57)Σ8O20(OH)4 and (K1.57Na0.31Ca0.03)Σ1.91(Al3.58Fe0.05Mg0.29Mn0.01)Σ3.93(Si6.70Al1.30)Σ8O20(OH)4, respectively. In addition, 1Mdillite, which is the polytype occurring in the common 1Mdto 2M1 prograde sequence, is relatively Mg poor, but coexists with Mg-rich illite in the Silverton Caldera sample.

These data confirm that 1M stacking is caused by compositional anomalies, and thus explain the lack of the 1M stacking sequence in normal diagenetic sequences in pelitic rocks, as most illite in such environments has a relatively small phengitic component. The parameter Δz, a measure of the corrugation of the oxygen sheets, may be the key parameter reflecting the polytypic state of dioctahedral and trioctahedral micaceous minerals. Such composition-determined relations may be related to the occurrence of 1M polytypism in glauconite and celadonite, both dioctahedral 2:1 clay minerals having large Mg or Fe octahedral-cation components, and in trioctahedral micas. Insofar as the 1M stacking sequence does not have the same composition as 2M1 material, these data confirm that the different varieties of illite are not polytypes, sensu stricto.

Differences in equilibration rates among crystals of different sizes may be used to deduce paleofluid changes over time if the crystal-growth mechanism is known. To explore isotopic equilibration rates as a function of illite growth, we studied B-isotope changes during illitization of smectite. Montmorillonite (<2.0 µm SWy-1, K saturated) was reacted with aqueous boric acid (1000 ppm B) at 300°C, 100 MPa in sealed Au capsules (1:1 fluid:mineral ratio). The initial fluid was 0‰ (NBS 951 standard) but after R1 ordering occurred (65 days of reaction) the fluid was changed to −7‰ in order to examine the rate of isotopic re-equilibration. Samples were taken intermittently throughout the experiment. Each aliquot was NH4 exchanged and size separated into fine (<0.2 µm), medium (0.2–2.0 µm) and coarse (>2.0 µm) fractions. The isotopic composition of B in the tetrahedral sheet was then measured for comparison with the predicted equilibrium values.

The fine fraction showed equilibrium isotope ratios within 10 days, indicating that small, newly nucleated crystals precipitate in equilibrium with the fluid under supersaturated, closed conditions. These fine-fraction minerals did not re-equilibrate when the fluid was changed. The medium fraction gradually equilibrated with the initial fluid as illite grew to values >50%, but did not re-equilibrate with the later fluid. The coarse fraction was slow to begin recrystallization, perhaps due to dissolution kinetics of large crystals or the presence of detrital contaminants. However, it showed the fastest rate of isotopic change with crystal growth after R1 ordering. We conclude that at 300°C, the initial B–O bonds formed in illite are stable, and isotopic re-equilibration only occurs on new crystal growth. Therefore, different isotope ratios are preserved in different crystal size fractions due to different rates of crystal growth. Large crystals may reflect equilibrium with recent fluid while smaller crystals may retain isotope compositions reflecting equilibrium with earlier fluids.

Soil aggregates consist of sand, silt, and clay size particles. Many of the clay size particles in soils are clay minerals, which actively influence soil behavior. The properties of clay minerals may change significantly as soil particle size decreases to the nanoscale; however, little information is available about these properties for the Ultisols in China. In the present study, the clay mineral components and structural characteristics of four particle-size fractions (i.e., <2000, 450–2000, 100–450, and 25–100 nm) of two Ultisol samples (Ult-1 and Ult-2) were investigated using elemental analysis, X-ray diffraction, Fouriertransform infrared spectroscopy, and thermal analysis. The molar SiO2 to Al2O3 ratios were lower in the nanoscale particle-size fraction (25–100 nm) than in the 450–2000 and <2000 nm fractions. This indicates greater desilicification and allitization of the smaller Ultisol particles. Furthermore, the Fe oxide and Al oxide contents increased and reached a maximum level in the 25–100 nm fraction of the two Ultisols. Goethite was mainly found in the 100–450 nm and 25–100 nm fractions. The dominant clay minerals in the Ultisol 25–100 nm fraction were kaolinite and illite with a small amount of a hydroxy-interlayered mineral in Ult-1 and gibbsite in Ult-2. The kaolinite crystallinity decreased as particle size decreased. The low crystallinity of the kaolinite in the A horizon 25–100 nm fraction was attributed to a reduction in the thickness of coherent scattering domains, as well as to decreases in OH groups and the dimensions of octahedral AlO6 sheets. A determination of the chemical and mineralogic properties of the different size fractions of the Ultisols is important to understand the desilicification and Al and Fe oxide enrichment mechanisms during soil formation. The significance of these results can help to reveal the nanoscale transformations of clay minerals. Analysis of clay mineral compositions in nanoparticles can provide the additional data needed to understand the adsorption and mobility of nutrients and pollutants.

The Art Discovery Group Catalogue is a virtual bibliographic resource based on the catalogues of over 70 art and museum libraries. Its future is closely linked to the question of technically and topically innovative data concepts on the one hand and to new retrieval and analysis procedures on the other. Will it be possible to interpret both the quantity and the diversity of the data in a more future-oriented and efficient way for scientific questions than traditional catalogues do?

The alteration of spodumene to cookeite has been identified in a Li-bearing aplite-pegmatite from northern Portugal. Optical microscopy and scanning and transmission electron microscopy (SEM/TEM) were used to characterize the alteration products in both cookeite + quartz and cookeite + kaolinite ± mica assemblages. Mutual relationships between the minerals were assessed using back-scattered electron imaging. The first assemblage occurs along the cleavage planes of spodumene, whereas the second forms as the result of spodumene breakdown. Fine mica grains surrounded the cookeite aggregates in the second assemblage only. Precipitations of cookeite and quartz in open pore spaces and parallel packets of cookeite and kaolinite were identified by TEM. Selected area electron diffraction carried out on cookeite identified a layer-stacking sequence from highly disordered to one-layer order-disorder with a lesser participation of two-layer polytypes. The thickness of one-layer cookeite packets averaged ∼85 −100 nm. Disordered cookeite has a mean thickness of 450 nm. The chemistry of cookeite was analyzed by both electron and ionmicroprobe techniques. The structural formula of cookeite from the first assemblage corresponds to: Al2.0(Si3.23Al0.766)O10(OH)2(Al1.80Li1.166Mg0.004Fe0.09)(OH)6. Two distinct compositional varieties were found: one corresponding to ideal cookeite, whereas the second belongs to the cookeite-donbassite join.

The thermodynamic stability field for the observed minerals was calculated using the SUPCRT® programme. Two distinct stages of cookeite crystallization are discussed. The lower pressure and temperature stability of the reaction of spodumene to cookeite + quartz were estimated at ∼2.4 kbar and 240°C. The cookeite + kaolinite ± mica assemblage is still in equilibrium with quartz at ∼2.2 kbar and 220°C. The lower limit for the stability of cookeite was found at 205°C and 2 kbar.

Upper Cretaceous—Danian chalk and interbedded clay-rich layers from wells of the South Arne Field and adjacent wells in the North Sea and from Stevns in Zealand have been investigated to determine the clay mineralogy in the chalk and the origin of the interbedded clay-rich layers. The mineralogy, with emphasis on clay mineralogy, was determined after removal of the calcite by dissolution at pH 4.5–5 in order to preserve the other minerals. Generally, mixed-layer minerals are the dominant clay minerals, except for two wells, Rigs-1 and Rigs-2, where a 3D ordered kaolinite prevails. A detailed structural characterization of the mixed-layer minerals was carried out by modeling of the X-ray diffraction (XRD) patterns. In most of the samples dominated by mixed-layer minerals, two mixed-layer phases, a high-smectite illite-smectite (I-S) and a low-smectite illite-smectite-chlorite (I-S-Ch), prevail, irrespective of depth or location of the samples. However, some samples contain I-S-Ch and ordered S-Ch, and others a chlorite-serpentine (Ch-Sr) phase, and these samples probably formed during diagenesis at higher temperatures. The clay-rich layers and the adjacent chalk have the same or quite similar clay mineralogy, both with respect to kaolinite vs. mixed-layer minerals and with respect to their detailed structure. In conclusion, the kaolinite is detrital and the I-S minerals formed in the chalk from volcanic ash. The main conclusion is that the clay-rich layers in the North Sea chalk formed by dissolution of the calcite in the chalk and that this dissolution took place at burial depths of >1 km, probably through migration of solutions through permeable chalk layers.

A Mg-rich palygorskite sample from phosphorite deposits of Ganntour (Morocco) with the structural formula ${\text{Si}}_8\left({\text{Mg}}_{2.6}{\text{Al}}_{1.19}{\text{Fe}}_{\text{0.33}}^{\text{III}}{\square }_{0.88}\right){\text{Ca}}_{0.056}{\text{Na}}_{0.024}{\text{K}}_{0.104}{\text{O}}_{20}{\left(\text{OH}\right)}_2{\left({\text{OH}}_2\right)}_{4\cdot }4{\text{H}}_2\text{O}$, was studied by FTIR spectroscopy. In both OH-stretching and OH-bending regions, there is evidence of dioctahedral Al2□OH, AlFe□OH and trioctahedral Mg3OH features, leading to a di-trioctahedral crystallochemical model of octahedral site occupancies in ribbons of Ganntour palygorskite.

This model, established through the IR spectroscopy study of a Mg-rich palygorskite, seems to be appropriate for many other palygorskites with lower Mg content in the octahedral sheet.

Selective sorption and/or fixation of cations with low hydration energies (e.g. K+, NH4+, Rb+, Cs+) by vermiculites is a well known phenomenon in soil science and it has been described by many investigators since the 1950s. Because most of the available studies deal with trioctahedral vermiculites, cation fixation in dioctahedral vermiculites is not as well understood as fixation by trioctahedral structures. The objective of the present study was to investigate the influence of NH4+ saturation on the structure of a natural dioctahedral vermiculite. Because no dioctahedral vermiculite standard reference material was available, two natural dioctahedral vermiculite-rich soil clay samples were used in the study. The clays were saturated with NH4+ using different protocols to simulate natural processes that likely take place in soils. The degree of NH4+ fixation by the dioctahedral vermiculite was evaluated using X-ray diffraction, elemental N analysis, and infrared spectroscopy. All the treatments that involved NH4+ saturation caused NH4+ fixation and irreversible collapse (i.e. contraction to ~10 Å) of at least a portion of the previously hydrated (vermiculitic) interlayers. Air drying of the NH4+-saturated samples greatly enhanced the degree of the collapse. The results indicated that the collapse of dioctahedral vermiculite leads to the formation of a NH4-illite-like phase that is likely to occur in some soils and sediments that are rich in organic matter. The formation of a NH4-illite-like phase by NHNH4+ fixation in vermiculitic interlayers needs to be taken into consideration in studies that deal with the clay mineralogy of sedimentary basins.

The adsorption of two dinitrophenol herbicides, 4,6-dinitro-o-cresol (DNOC) and 4,6-dinitro-o-sec-butyl phenol (dinoseb), by two reference smectite clays (SWy-2 and SAz-1) was evaluated using a combination of sorption isotherms, Fourier transformation infrared (FTIR) spectroscopy, X-ray diffraction (XRD) and molecular dynamic simulations. Clays were subject to saturation with various cations, and charge reduction. The DNOC adsorption decreased with increasing pH indicating that DNOC was primarily adsorbed as the neutral species. The FTIR spectra of DNOC-clay films showed that DNOC molecules are oriented parallel to the clay surface. Interlayer cations have a strong effect on adsorption depending largely on their hydration energies. Weakly hydrated cations, e.g. K+ and Cs+, resulted in greater sorption compared to more strongly hydrated cations such as Na+ or Ca2+. Lower hydration favors direct interactions of exchangeable cations with -NO2 groups of DNOC and manifests optimal interlayer spacings for adsorption. In the presence of sorbed DNOC, an interlayer spacing for K-SWy-2 of between 12 and 12.5 Å was maintained regardless of the presence of water. This d-spacing allowed DNOC molecules to interact simultaneously with the opposing clay layers thus minimizing contact of DNOC with water. The charge density of clays also affected sorption by controlling the size of adsorption domains. Accordingly, DNOC adsorption by low-charge clay (K-SWy-2) was much higher than by high-charge clay (K-SAz-1) and Li-charge reduction greatly enhanced dinoseb adsorption by K-SAz-1. Steric constraints were also evident from the observation that adsorption of DNOC, which contains a methyl substituent, was much greater than dinoseb, which contains a bulkier isobutyl group. Adsorption of DNOC by K-SAz-1 was not affected in the presence of dinoseb, whereas dinoseb adsorption was greatly reduced in the presence of DNOC.

During the reign of Elizabeth I the ecclesial and legal ‘revolution’ under Henry VIII, to establish in England a national church under the royal supremacy, was converted into a ‘settlement’. It steered a course between radical puritans and recusant Catholics. Clothed in legal propriety, this settlement was articulated both juristically and theologically by the great Richard Hooker (d. 1600). After the return to Rome under Mary, the Elizabethan Acts of Parliament re-established the English Church, revived legislation made under Henry VIII and Edward VI, and imposed uniformity in worship. The period also sees the use of ‘soft-law’, like Articles, Admonitions, and Advertisements. Parliament rejects the Reformatio Legum Ecclesiasticarum in 1571, but Canons were passed piecemeal in 1571, 1575, 1585, and 1598. The turn of the Welsh Tudors to rule ended in 1603. The Scottish Stuarts came next. The reign of James I (1603–1625) saw bitter dispute between the King and the common lawyers over the royal supremacy in matters ecclesiastical. But there was one lasting legal landmark: the Canons Ecclesiastical 1603/4. This new code was studied theologically by a contemporary cleric, Francis Mason. Whilst several notable civilians from that time have become well-known – such as John Cowell (d. 1611), Daniel Dun (d. 1617), Clement Colmore (d. 1619), and Thomas Ridley (d. 1629), Francis Mason is largely unknown. However, he is very worthy of inclusion in the canon of Anglican priest-jurists. What follows sketches the life and career of Mason, outlines his treatise on the Canons, and discusses that treatise in a wider context, including comparing it with a similar work by Bishop Edward Stillngfleet (d. 1699).