The Al13 polycation is the predominant hydroxy-Al species in partially neutralized solutions. However, the existence of the Al13 species and the factors governing its formation in terrestrial environments still remain obscure. The objective of this study was to investigate the influence of pyrogallol, a common polyphenol in soils, on the formation of Al13 tridecamer. Hydroxy-Al solutions with an OH/Al molar ratio of 2.2 (pH 4.53) at pyrogallol/Al molar ratios of 0, 0.01, 0.05, 0.1 and 0.5 were prepared and mixed with 0.5 M sodium sulfate to form aluminum sulfate precipitation products. The solid-state 27Al nuclear magnetic resonance (NMR) spectra of the precipitates show that the pyrogallol perturbed the formation of Al13 tridecamer species as indicated by the decrease in the intensity of resonance peak, observed at 62.5 ppm, with increase in the pyrogallol/Al molar ratio. The crystallization of the precipitated Al sulfates was also hampered by pyrogallol, resulting in the formation of X-ray non-crystalline products at a pyrogallol/Al molar ratio of 0.50. The absorbance at 465 and 650 nm of the hydroxy-Al-pyrogallol solutions, the C coprecipitated, the electron spin resonance and 13C CPMAS-NMR spectra of the precipitates indicate the concomitant enhanced abiotic humification of pyrogallol by the X-ray amorphous Al species.

The golden age of human rights is over, as is the time when rights protection systems developed in a favorable context. Multilateralism is under attack from all sides, authoritarian countries are in the majority around the world, and democracies are increasingly fragile. The resurgence of claims about national sovereignty against universal human rights is part of a global geopolitical context in which authoritarianism and populism are permeating national political scenes. In this context, it is important to understand how regional systems for the protection of human rights manage to continue functioning, to convince states to implement the judgments of the courts, and to avoid denouncing their jurisdiction.

Stacking disorder in celadonite, a dioctahedral mica with Fe and Mg as major octahedral cations and which generally adopts the 1M stacking sequence, was investigated mainly by using transmission electron microscopy (TEM). The selected-area electron diffraction patterns with 0kl reflections along the [100] beam direction correspond to the 1M stacking but those along the [110], $\left[1\overline{1}0\right]$\$\end{document}, [010], [310], and $\left[3\overline{1}0\right]$\$\end{document} directions are frequently streaked along the [001]* direction or contain extra spots from twinned domains. Three-dimensional stacking analyses using sets of two high-resolution TEM images along different directions of the same area of one crystal indicate that all stacking faults involve only 180° layer rotations. These stacking faults produce greater peaks of 0kl reflections than expected in powder X-ray diffraction (XRD) patterns. Simulation of the XRD patterns indicated that 180° layer rotations occur at >10% of total interlayer regions in one celadonite specimen. The interlayer region of celadonite is characterized by a near-zero ditrigonal rotation angle, a small surface corrugation of the basal oxygen plane, and a small amount of Al substitution in the tetrahedral sheets. These features suggest that there is no preference for any of the six stacking angles around the interlayer region. The abundance of 180° layer rotation rather than ±60° and ±120° in the present specimens may be related to their ribbon-like morphologies elongated along the a axis.

Developing low cost and effective phosphate adsorbents is crucial to prevent eutrophication of natural waters. Here, phosphate removal by a natural and abundant shale from the Ivory Coast was investigated in both batch and column experiments with special attention devoted to understand the adsorption process. Batch experiments were carried out to assess the influence of initial phosphate concentration, sorbent dosage, contact time, and pH on phosphate removal. The phosphate removal efficiency increased with increased shale dosage while phosphate uptake decreased. Aqueous Ca, Mg, Al, and Fe species concentrations decreased in the presence of phosphate. Additionally, phosphate uptake strongly decreased with pH increases in the range 2–11, but then increased at pH 12. The kinetics were well described using a pseudo-second order model, and Langmuir adsorption isotherms were used for the equilibrium surface reactions. Adsorption to nanoparticles of goethite was hypothesized to be the major phosphate removal mechanism in the pH range 4–10. Column experiments with a flow rate of 1 mL min−1 and an initial phosphate concentration of 25 mg L−1 showed a breakthrough point at a V/Vp value of ~17, where Vis the volume of phosphate solution added to the column and Vp is the pore volume. A V/Vp value of ~17 corresponded to a phosphate uptake of 0.17 mg/g, which was in agreement with the batch experiments. Column experiments revealed a strong correlation between the aqueous concentrations of Ca, Mg, Al, and Fe species and phosphate removal and, thus, suggest that phosphate removal by the shale occurred by aqueous dissolution/precipitation.

Fougerite (IMA 2003-057) is a mixed M(II)-M(III) hydroxysalt of the green rust group, where M(II) can be Fe or Mg, and M(III) is Fe. The general structural formula is: ${[{\text{Fe}}_{1-}^{2+}x{\text{Fe}}_x^{3+}{\text{Mg}}_y{(\text{OH})}_{2+2y}]}^{+x}{[x\text{/}n{A}^{-n}.m{\text{H}}_2\text{O}]}^{-x}$ where A is the interlayer anion and n its valency, with 1/4 ≼ x/(1+y) ≼ 1/3 and m ≼ (1−x+y). The structure of green rusts and parent minerals can accommodate a variety of anions, such as OH−, Cl−, ${\text{CO}}_3^{2-},{\text{SO}}_4^{2-}$${\rm{CO}}_3^{2 - },\;{\rm{SO}}_4^{2 - }$. The structure of the mineral was studied by Mössbauer, Raman and X-ray absorption spectroscopies (XAS) at the FeK edge. Mössbauer spectra of the mineral obtained at 78 K are best fitted with four doublets: D1 and D2 due to Fe2+ (isomer shift δ ≈ 1.27 and 1.25 mm s−1, quadrupole splitting ΔEQ ≈ 2.86 and 2.48 mm s−1, respectively) and D3 and D4 due to Fe3+ (δ ≈ 0.46 mm s−1, ΔEQ ≈ 0.48 and 0.97 mm s−1, respectively). Microprobe Raman spectra obtained with a laser at 514.53 nm show the characteristic bands of synthetic green rusts at 427 and 518 cm−1. X-ray absorption spectroscopy shows that Mg is present in the mineral in addition to Fe, that the space group is and the lattice parameter a ≈ 0.30–0.32 nm. The mineral forms by partial oxidation and hydrolysis of aqueous Fe2+, to give small crystals (400–500 nm) in the form of hexagonal plates. The mineral is unstable in air and transforms to lepidocrocite or goethite. The name is for the locality of the occurrence, a forested Gleysol near Fougères, Brittany, France. Its characteristic blue-green color (5BG6/1 in the Munsell system) has long been used as a universal criterion in soil classification to identify Gleysols. From a thermodynamic model of soil-solution equilibria, it was proposed that for the eponymous mineral, Fougères-fougerite, OH− may be the interlayer anion. In other environments, the interlayer anion may be different, and other varieties of fougerite may exist. Fougerite plays a key role in the pathways of formation of Fe oxides.

The Kütahya kaolinite deposits are the most important source of raw materials for the ceramics industry in Turkey. To date, no detailed mineralogical or geochemical characterizations of these materials have been carried out; the present study aims to fill that gap. The Kütahya kaolinite deposits formed by alteration of dacite and andesite tuffs related to Neogene volcanism whichwas associated withe xtensional tectonics. The kaolinite deposits contain silica and Fe- and Ti-bearing phases (pyrite, goethite, and rutile) in vertical and subvertical veins that diminish and then disappear upward. Mineralogical zonation outward from the main kaolinite deposit is as follows: kaolinite ± smectite + illite + opal-CT + feldspar; feldspar + kaolinite + quartz + smectite + illite; quartz + feldspar + volcanic glass. The veins and mineral distributions demonstrate that hydrothermal alteration was the main process in the development of the kaolinite deposits of the area. The very sharp, intense, diagnostic basal reflections at 7.2 and 3.57 Å, as well as non-basal reflections, well defined pseudohexagonal to hexagonal crystallinity with regular outlines, ideal differential thermal analysis-thermal gravimetric curves, and ideal, sharp, infrared spectral bands indicate well crystallized kaolinite. Micromorphologically, the development of kaolinite plates at the edges of altered feldspar and devitrified volcanic glass indicates an authigenic origin. Lateral increase in (SiO2+Fe2O3+MgO+Na2O+CaO+K2O)/(Al2O3+TiO2) from the center of the kaolinite deposit outward also indicates hydrothermal zonation. Enrichment of Sr in altered and partially altered rocks relative to freshvolca nic-rock samples demonstrates retention of Sr and depletion of Rb, Ba, Ca, and K during hydrothermal alteration of sanidine and plagioclase within the volcanic units. In addition, depletion of heavy rare earth elements (HREE) relative to light rare earth elements (LREE) in the kaolinized materials may be attributed to the alteration of hornblende. The negative Eu anomaly suggests the alteration of feldspar by hydrothermal fluids. The isotopic data from kaolinite and smectite indicate that hydrothermalalteration processes developed at 119.1–186.9°C and 61.8–84.5°C, respectively. Thus, the kaolinite deposits formed by hydrothermal alteration of volcanic glass, feldspar, and hornblende by a dissolutionprecipitation mechanism which operated under acidic conditions within Neogene dacite, andesite, and tuffs.

Former SHGAPE president Walter Nugent passed away in 2021. On April 1, 2023, historians gathered at the Organization of American Historians (OAH) annual meeting in Los Angeles, California, to remember him. William Deverell, Nancy Unger, Donna Gabaccia, Alan Lessoff, Charles Postel, and Annette Atkins spoke about Walter Nugent as a scholar, a colleague, a mentor, and a friend; then the audience joined in with their own memories and stories. The following roundtable is a lightly edited version of the panelists’ comments from that day, including an introduction that William Deverell wrote for the journal. We have included a Walter Nugent Reading List at the end—a selected bibliography of his books and articles, as well as works about him.

The polymer model provides a relatively simple and robust basis for estimating the standard Gibbs free energies of formation (ΔGfo) and standard enthalpies of formation (ΔHfo) of clay minerals and other aluminosilicates with an accuracy that is comparable to or better than can be obtained using alternative techniques. The model developed in the present study for zeolites entailed the selection of internally consistent standard thermodynamic properties for model components, calibration of adjustable model parameters using a linear regression technique constrained by ΔGfo and ΔHfo values retrieved from calorimetric, solubility, and phase-equilibrium experiments, and assessments of model accuracy based on comparisons of predicted values with experimental counterparts not included in the calibration dataset. The ΔGfo and ΔHfo predictions were found to average within ±0.2% and ±0.3%, respectively, of experimental values at 298.15 K and 1 bar. The latter result is comparable to the good accuracy that has been obtained by others using a more rigorous electronegativity-based model for ΔHfo that accounts explicitly for differences in zeolite structure based on differences in framework density and unit-cell volume. This observation is consistent with recent calorimetric studies indicating that enthalpies of transition from quartz to various pure-silica zeolite frameworks (zeosils) are small and only weakly dependent on framework type, and suggests that the effects on ΔHfo of differences in framework topology can be ignored for estimation purposes without incurring a significant loss of accuracy. The relative simplicity of the polymer model, together with its applicability to both zeolites and clay minerals, is based on a common set of experimentally determined and internally consistent thermodynamic properties for model components. These attributes are particularly well suited for studies of the effects of water-rock-barrier interactions on the long-term safety of geologic repositories for high-level nuclear waste (HLW).

Montmorillonite-rich clays are important in many engineering applications. The compressibility of such plastic clays at high consolidation pressures is important for predicting routine settlement and for applications in nuclear-waste repositories. Laboratory measurement of compressibility data at high consolidation pressures is not only time consuming but very expensive also. Theoretical predictions can help to determine the compressibility of plastic clays at high consolidation pressures. A linear relationship between e/eNvs. 1/√P (eN is the normalization void ratio at normalization pressure N and P is the consolidation pressure) was derived using diffuse double-layer theory. The compressibility data of several plastic clays in published studies were found to support the derived relationship. A generalized theoretical equation was proposed to predict the compressibility data over a wide range of consolidation pressures using an experimentally measured void ratio at low consolidation pressure. The compressibility data for different plastic clays were predicted accurately up to maximum consolidation pressures that ranged from 0.7 to 30 MPa using an experimentally measured void ratio near the pre-consolidation pressure. The preconsolidation pressures for different clays considered here ranged from 25 to 133 kPa. The proposed predictive model is supported by experimental data, is simple, and does not require knowledge of clay-surface and pore-fluid parameters.

The presence of pharmaceutical pollutants in the environment is one of the most pressing environmental problems. Adsorption from solution is an effective way to remove pharmaceuticals from liquid media, but the problem then is to separate the adsorbent from the liquids. The objective of the present study was to remove nitrofurazone from aqueous solutions using a bentonite/magnetite composite, prepared by co-precipitation of magnetite with bentonite, which could then be collected by magnetic separation. The bentonite/magnetite composite was characterized using diverse techniques, such as X-ray diffraction, scanning electron microscopy, low-temperature N2 adsorption/desorption, laser diffraction, and magnetization measurements. The particle size of the composite material did not exceed 50 μm and the particle size distribution was mono-modal with a maximum at 3.2 μm. The strong hysteresis in the magnetization curve revealed that the bentonite/magnetite particles were ferromagnetic. Adsorption of nitrofurazone by the bentonite/magnetite composite from aqueous solutions was measured and the amount of nitrofurazone adsorbed was 3.2×10–2 mmol/g. The adsorption kinetics of nitrofurazone to the bentonite/magnetite composite followed a pseudo-second-order kinetics equation. Upon adsorption, hydrogen bonds were formed between the amide groups of nitrofurazone and oxygen groups in bentonite.

Adsorption by synthetic 2-line ferrihydrite and hematite of glyphosate and phosphate, separately and together, was compared with adsorption results for goethite, gibbsite and two kaolinites in order to determine adsorption differences and similarities, in particular competition and phosphate preference, of these variable-charge minerals. Hematite rapidly adsorbed both compounds, while adsorption by ferrihydrite was slow, in particular of glyphosate, probably because of very slow diffusion of the bulky glyphosate molecules into interior sites in ferrihydrite particles. Accordingly, the Langmuir adsorption capacity of glyphosate (GAC) was considerably smaller (1.85 µmol m−2)than GAC for hematite (2.61 µmol m−2). The phosphate adsorption capacities (PAC) for ferrihydrite and hematite were more alike, 2.91 µmol m−2 and 2.85 µmol m−2, respectively. Differences between surface coordination (mono- or bidentate) may also contribute to the observed differences but conflicting information about the nature of the surface complexes makes this a difficult contributary factor to assess. The minerals were found to exhibit great variation in extent of competition and phosphate preference. Little competition and phosphate preference characterized hematite adsorption, while phosphate almost completely outcompeted glyphosate on goethite; ferrihydrite adsorption fell between these extremes. These differences may be attributed to different numbers of common (competitive) and specific (selective) adsorption sites on the three Fe oxides with a decreasing number of common sites in the order: goethite>>ferrihydrite>hematite, i.e. almost all goethite sites are common but with strong phosphate preference, while most hematite sites are specific for either glyphosate or phosphate. Alternatively, the result may be explained by adsorption in more planes, e.g. glyphosate adsorption onto the inner-Helmholtz-plane-adsorbed phosphate. For all six minerals compared, desorption of glyphosate following phosphate addition was found to be significantly correlated with the difference between the amounts of phosphate and glyphosate adsorbed indicating that this difference may be used as a competition index for predicting the influence of phosphate on glyphosate adsorption.

The most common means of reducing the particle size of solids is by grinding, a process which can affect the surface properties and the behavior of the solid in later stages (granulation, compaction, etc.), and which can influence the end-use properties of the final product. Inverse gas chromatography (IGC) measurements were used here to evaluate the influence of grinding, in a ball mill, on attapulgite. The milling experiments were performed in dry media for various periods. After 30 min of grinding, significant decreases in the particle size and specific surface areas were observed when calculated using different probes. No noticeable variation in the surface properties was observed by IGC either at infinite dilution or at finite concentration, however. In particular, the distribution functions of the adsorption energies (DFAE), giving information about the surface heterogeneity for both an apolar probe (octane) and a polar probe (isopropanol), remained unchanged, regardless of the grinding time. The stability of the surface energy with respect to the grinding process was seen to be related to the particular fibrous structure of the attapulgite clay.

This article examines the different uses made of a marble ostotheke (ossuary) that was discovered in 2021 during archaeological excavations in and around the church in the Araplıtepe district, near the ancient city of Metropolis. Information about the chest’s original use as a funerary object and its production date and ownership is followed by a discussion of its recycled (spolia) use as a sedimentation tank on a water channel, and by an explanation of its third and final function. A bronze lamp discovered inside the ostotheke provides important clues about the object’s final use and its relationship with its surroundings. Christian burials in and around the church dating to as early as the fifth to sixth centuries AD also provide insights into these processes. This ostotheke, which served a variety of functions from the second to the seventh centuries AD, shows that objects made in Roman times might continue to be used in different ways for a long time thereafter. This article therefore examines the ostotheke as a reflection and extension of the changing needs of people and communities over time, rather than simply as a carved marble object.

Bacterial mineralization in weathered pyroclastic deposits of the Kaimondake volcanic ash (4040 ybp) and the Koya pyroclastic flow (6400 ybp) was investigated to evaluate the impacts of bacteria on mineral formation, and to characterize the microbiogenic minerals in the weathering environment. The mineralogy of abiogenic weathering products was also investigated for comparison with the microbiogenic products, and mineral saturation indices were calculated for porewaters using the PHREEQC computer code. The results indicated that these weathered pyroclastic deposits contain 108–109 cells/g, consisting of spherical to rod-shaped bacteria. Associated abiogenic allophane had an Al/Si ratio ranging from 1.01 to 2.13. The bacterial cell surfaces were completely or partially covered by poorly-ordered silicate minerals, which could be divided into two groups based on their chemical and morphological characteristics. Group I was characterized by well developed fibrous to smectite-like flaky habits with variable Al, Si and Fe, corresponding to compositions between proto-imogolite allophane and chamosite. These Al-Si-Fe minerals were the most abundant and major microbiogenic products in both lithologies. Group II exhibited poorly-developed aggregates of allophane-like granular materials composed mainly of Al and Si with minor Fe. Geochemical calculations revealed that the porewaters were saturated with respect to allophane and other crystalline clay minerals such as halloysite, kaolinite, montmorillonite and nontronite. These microbiogenic minerals may be formed as the earliest phase of these clay minerals after interaction of the bacterial cell surfaces with dissolved cations mainly Si, Al and Fe, in the porewaters.

Low-charge beidellites were synthesized by a hydrothermal treatment applied to an amorphous gel phase in basic solution. The hydrothermal conditions for the syntheses were chosen from the stability field of beidellite previously investigated in the literature. The synthetic samples were characterized chemically and structurally using X-ray diffraction, infrared spectroscopy, cation exchange capacity measurement, and chemical and thermal analyses. We compared the synthetic sample with a natural beidellite sample (SbId) from Idaho, USA, looking at chemical composition and particle size. The main difference is the octahedral site occupancy (cis- or trans-vacant layer structure). The natural SbId sample has trans-vacant layers and the synthetic sample has a preferentially cis-vacant character. This character can be modulated, using specific synthesis conditions. The cis- or trans-vacant layer structure of various synthetic beidellites was investigated at low temperature (<350°C) and pressure (<25 MPa). Depending on the pressure and/or synthesis temperature, the proportion of cis-vacant layers ranges from 20 to 100% and increases with the layer-charge deficit.