Contamination of the environment with heavy metals, including cationic radionuclides, is a serious problem which has yet to be fully overcome. A class of potentially effective cation exchangers for sequestering heavy metals which has received little attention is K-depleted mica. The purpose of this study was to investigate the heavy-metal cation exchange properties of K-depleted phlogopite and biotite, which were prepared from a natural phlogopite and biotite, respectively, using sodium tetraphenylborate (NaTPB). The X-ray diffraction (XRD) patterns showed that interlayer K+ ions were completely replaced with exchangeable Na+ ions, resulting in the expansion of the d001 spacing of both K-depleted phlogopite and K-depleted biotite. In order to investigate the cation exchange selectivity of K-depleted phlogopite and biotite for Co2+ and Ni2+, cation exchange isotherms and Kielland plots were constructed. The isotherms and Kielland plots indicated that both K-depleted phlogopite and biotite are highly selective for Co2+ as well as Ni2+. The XRD patterns after both 2Na+ → Co2+ and Ni2+ exchange reactions suggest that double sheets of interlayer water are present in the interlayer. These K-depleted micas are potential cation exchange materials for removal of some heavy metals such as Ni and radioactive species such as 60Co from solution.

The flavonoid naringin is the main source of the undesirable bitter taste in some citrus juices. In commercial debittering processes, the naringin is adsorbed on non-ionic polymeric resins. Organo-clays (OCs), which have been used as sorbents for organic pollutants, could also have affinity for the naringin molecule, and thus potentially could serve as a debittering agent. The objective of the present study was to characterize the sorption capacity of a prepared OC to evaluate its ability to remove naringin from aqueous solutions, investigating the effect of adsorbent dose, initial concentration of naringin, temperature, contact time, and pH. The OC was prepared by the intercalation of cationic surfactant hexadecyltrimethylammonium bromide in a Mexican bentonite. The host clay and the OC were characterized by X-ray diffraction, Fourier-transform infrared, and nitrogen gas adsorption. The OC showed a surface area of 9.3 m2 g-1, 11.35 nm average pore diameter, and a basal spacing, d001, of 2.01 nm. The adsorbent removed naringin at the rate of 60-72% at 25°C and pH 3. The sorption capacity increased with pH and temperature. Experimental data were well fitted by both Langmuir and Freundlich adsorption models. Most of the sorption took place during the first 10 min and the equilibrium time was reached within 720 min. The rate of sorption was adjusted to pseudo second-order kinetics.

The strong adsorption to kaolinite of four polyaromatic, cationic dyes (9-aminoacridine, 3,6-diaminoacridine, azure A and safranin O), which adsorb much less to alumina or silica, was investigated by means of acid-base titrations, measurements of adsorption at varying pH and dye concentration, and by ATR-FTIR spectroscopy. The four dyes adsorb to kaolinite to similar extents, with little change over the pH range 3–10, but at higher pH (above the pKas of the dyes) the adsorption of 9-aminoacridine and 3,6-diaminoacridine decreases, that of azure A increases, and that of safranin O stays approximately constant. Although the dyes adsorb to kaolinite much more strongly than metal ions do, titration and spectroscopic data show that there is only limited chemical interaction between the adsorbed dyes and the kaolinite surface. The results indicate that electrostatic interaction between the dye molecules and the kaolinite surface is necessary for adsorption, but that hydrophobic interactions also contribute. It is proposed that the relatively hydrophobic silica faces of kaolinite, which carry low-density permanent negative charge, facilitate aggregation and adsorption of the positively charged, flat, aromatic dye molecules.

Explanations for the successful expansion and consolidation of the European Union and its legal system have long emphasized the importance of domestic courts’ sending preliminary references to the Court of Justice. Key to many of these theoretical accounts is the claim that domestic courts are better equipped than the Court of Justice to compel national governments to comply with EU law. Integrating insights from the comparative judicial politics literature into the context of the EU's preliminary references system, we provide a theoretical and empirical foundation for this claim by arguing that incorporating domestic courts into the EU legal process enhances public support for expansive judicial interpretations of EU law. We go on to argue, however, that this transfer of legitimacy depends on citizens’ views of the national and European courts. We support our argument with evidence from a preregistered survey experiment fielded in Germany.

The Söğüt kaolinite deposits at Çaltı, İnhisar, and Küre, Turkey, are an important source of raw materials for the ceramics industry of that country, but no detailed mineralogical or geochemical characterizations of these economically important materials have been carried out to date. The purpose of this study was to fill this gap by performing mineralogical, geochemical, and isotopic characterizations of these kaolinite deposits which occur within Paleozoic granite-granodiorite complexes that are crosscut by aplite and pegmatite dikes, and overlain by Neogene sedimentary units. These units are dominated by quartz veins and networks of subvertical fractures and weak zones that were invaded by hydrothermal fluids, resulting in their kaolinization and silicification. Altered units and related host rocks were examined using polarized-light microscopy, X-ray diffractometry, scanning electron microscopy, infrared spectroscopy, and chemical and isotopic methods. Feldspar crystals are either sericitized or kaolinized, and mica exhibits partial chloritization; Fe-Ti-Mn oxides occur within fractures. Kaolinite crystals occur in authigenic vermiform or plate-like stacked forms, having contacts with resorbed feldspar crystals which locally exhibit thick, platy, and subparallel orientations relative to microfractures, the pathways for hydrothermal-fluid injection. Altered feldspar relicts are associated mainly with kaolinite, smectite, quartz crystals, and illite/mica. Increase in (Al+Fe)/Si in the kaolinized units (relative to host-rock granite and granodiorite complexes and silicification), depletion of Ba+Rb, and a negative Eu anomaly reveal that the alteration of feldspar by hydrothermal fluid, the character of which was determined from O- and H-isotopic values, resulted in the precipitation of kaolinite. Thus, the Söğüt kaolinite deposit possibly formed by hydrothermal alteration and a feldspar dissolution-precipitation mechanism in both the granite-granodiorites complexes and related overlying sedimentary units under acidic environmental conditions, which developed via depletion of the soluble elements Na and Ca.

Removing trace water from oil is an important industrial process and is commonly accomplished using vacuum filtration. The drawbacks of this method, however, are: poor efficiency, large oil loss, and significant energy consumption. The objective of the current study was to develop a better system to solve these problems using a sodium polyacrylate (PAA-Na)-modified bentonite as the dehydrating agent and, for the first time, to apply it to transformer oil. PAA-Na was prepared by aqueous solution polymerization. A dehydration test was carried out to determine the optimum addition of PAA-Na, and the highest dehydration rate of 76.5% was obtained with the addition of 20 wt.% PAA-Na. The steady dehydration rate of the PAA-Na-modified bentonite was better than that of other adsorbents (calcium chloride, zeolite 5A, unmodified bentonite). The process of adsorbing saturated water vapor on PAA-Na modified bentonite was studied and interpreted from the aspects of adsorption isotherms and thermodynamic properties. The results showed that the adsorption isotherm data followed the Freundlich isotherm model and the thermodynamic parameters indicated that the process was endothermic. Fourier-transform infrared spectroscopy results revealed that PAA-Na was synthesized successfully and it had a huge proportion of hydrophilic groups. According to thermogravimetric analysis, the PAA-Na-modified bentonite was stable up to 200°C, giving a flexible region for pretreatment and regeneration. X-ray diffraction showed no change in the diffraction pattern before and after modification. Moreover, considering the results of scanning electron microscopy and surface-area analyses, one may safely say that PAA-Na was distributed homogeneously on the surface of the bentonite. In addition, PAA-Na-modified bentonite exhibited a high dehydration rate in xylene, naphtha, and diesel, indicating a broad range of applications.

The thermal behavior of two clinoptilolites from an epiclastic and a pyroclastic deposit of central-northern Sardinia and of their exchanged forms (Li, Na, K, Cs, Mg, Ca, Sr and ammonium) were investigated by differential thermal analysis and thermogravimetry up to 1000°C. Their thermal stability was studied by evaluating the residual crystallinity (expressed as rehydration capacity) after 2 h thermal treatments at 450, 600 and 900°C. The water loss at 1000°C was linearly related to the radius (r) and the charge (z) of the exchangeable cations by the equations r2/z or r3/z, which are proportional to the inverse of the charge density over the surface or to the charge density over the volume of the cations.

The cation composition plays a crucial role in determining the thermal behavior of clinoptilolite. The presence of cations such as Cs or K, which have low surface or volume charge densities, was found to increase the thermal resistance. In particular, the crystallinity of Cs- and K-exchanged forms of both clinoptilolites was not affected by thermal treatment at 450°C and was only slightly reduced by thermal treatment at 600°C.

Predicting the thermal behavior of natural and cation-exchanged forms of these clinoptilolites can provide useful information for possible applications in catalysis, in the case of high thermal stability, or for thermal transformation into ceramics or lightweight aggregates.

Powder-type semiconductor photocatalysts are widely applicable but their defects (e.g. easy agglomeration during preparation and recyclability in the suspension system) limit their practical application. In the current study, perovskite oxide photocatalytic material was loaded onto a muscovite substrate to overcome the problems of low stability, easy agglomeration, and difficult recovery. A photocatalytically active LaNi0.95Fe0.05O3/muscovite composite material was synthesized by a sol-gel impregnation method. Phase composition, morphology, and interfacial interaction of the composites, denoted as LNFBY-x (x: mass ratio of LNF to muscovite), were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and other analytical methods. According to the results, the particle size of LNF nanoparticles was regulated effectively by compounding with muscovite, and the agglomeration of LNF decreased. LNF nanoparticles were distributed evenly and attached in dense fashion to the surface of muscovite, thereby increasing the contact area with the reaction medium. The nanoparticles were connected to the silicon-oxygen tetrahedral sheet of the muscovite via Si–O–La, Si–O–Ni, and Si–O–Fe bonds, which increased the bonding strength between the composite components and expedited the transfer of photogenerated charge. More highly active oxygen species were produced, and a growing number of chemically active moieties (٠O2- and ٠OH) was generated in the photocatalytic reaction. LNFBY-1.00 demonstrated the best photocatalytic activity. A degradation rate of methyl orange of 99.03% was achieved after visible-light irradiation for 120 min, which decreased to 75.75% after five repeated uses, thereby indicating high stability and recycling ability. The photocatalytic LaNi0.95Fe0.05O3/muscovite composite material exhibited potential for application in environmental remediation practices.

X-ray diffraction (XRD) of powdered materials is one of the most common methods used for structural characterization as well as for the quantification of mineral contents in mixtures. The application of the Rietveld method for that purpose requires structure models for each phase. The recursive calculation of structure factors was applied here to the Rietveld refinement of XRD powder patterns of illite-smectite (I-S) minerals. This approach allowed implementation of stacking disorder in structural models. Models for disordered stacking of cis-vacant and trans-vacant dioctahedral 2:1 layers as well as rotational disorder were combined with models for mixed layering of illitic and smectitic layers.

The DIFFaX code was used to simulate non-basal (hk) reflections of illites with different degrees of disorder. Rietveld refinements of these simulated patterns were used to evaluate the application of this new approach. A model describing rotational disorder (n·120° and n·60° rotations) and mixed layering of cis-vacant and trans-vacant dioctahedral layers was tested. Different starting parameters led to identical results within the ranges of standard deviations and confirmed the stability of the automatic refinement procedure. The influence on the refinement result of an incorrect choice of fixed parameters was demonstrated.

The hk model was combined with models describing the basal reflections of disordered I-S and tested on measured data. A glauconitic mineral (Urkut, Hungary), an ordered I-S (ISCz-1, a special clay in the Source Clays Repository of The Clay Minerals Society), and a dioctahedral I-S (F4, Füzérradvány, Hungary) were used as test substances. Parameters describing the mixed layering of illitic and smectitic layers were compared with the results from refinements of oriented mounts and showed good agreement. A pattern of a physical mixture of an I-S mineral and a turbostratically disordered smectite was analyzed in order to test the new approach for application in quantitative phase analysis. The quantitative Rietveld phase analysis results were found to be satisfactory.

Short- and long-term exposure to inorganic solutions can cause significant degradation of the hydraulic properties of bentonite clay used in geosynthetic clay liners (GCLs). In particular, the increase in hydraulic conductivity due to cation exchange when Na-montmorillonite is subjected to leachates rich in Ca and Mg has caused problems in incinerator ash landfill liners located in wet environments, where large quantities of leachates are generated. Experimental results are presented to evaluate the immediate change in hydraulic conductivity of seven types of GCL clays upon permeation with leachate generated from three ash landfills. The composition of the ash, which is a by-product of the incineration of municipal solid waste (MSW), in turn influences the composition of the resulting leachate. Falling head permeability tests were performed on flexible-wall permeameter specimens, with back-pressure saturation. Chemical analysis shows that the three leachate products contain high, medium, and low concentration Ca and Mg cations. The clay component of GCL materials tested in this study consists of regular and polymer-treated bentonite. Polymer treatment is believed to render the clay non-reactive to many organic and inorganic chemicals. The results of this study indicate that: (1) polymer treatment is generally more beneficial if the clay is first saturated with water and not directly with the leachate; (2) high swell potential of the bentonite is more advantageous than polymer treatment, especially when low hydraulic conductivity is required in the short term and if the clay is pre-hydrated. Experiment setup and special specimen preparation procedures are also discussed.

Ranulf Higden's Polychronicon was the most widely read Latin chronicle of late medieval England. It (and its later continuations) influenced the production of several major chronicles that are frequently employed by scholars of the period, such as the Eulogium historiarum, Henry Knighton's Chronicle, John of Reading's Chronicle, John of Tynemouth's Historia aurea, and Thomas Walsingham's Chronica maiora. The continuations to 1377 are particularly valuable for providing contemporary narratives on the latter years of Edward III's reign, a period which saw hardly any independent historical narrative. Despite this, knowledge of the Polychronicon and its continuations has remained rather opaque and spotty. This article provides an assessment of the texts and manuscripts of the Polychronicon and its continuations to 1377 and beyond and serves as a starting point for further study and the production of much-needed critical editions. It lays out clear details on the development of these texts, including dates of composition and textual relationships. It newly identifies three previously unknown continuations, Crowland (for 1339), Suffolk (1340–73), and Abingdon (1380–1400), and offers information on several little-known continuations past 1377. This article also corrects many errors in previously available knowledge on these texts. It concludes with a detailed list of 188 manuscripts, adding to and correcting the 162 manuscripts scattered across previous works in varying degrees of detail.

The oil sands of western Canada represent the third largest hydrocarbon deposit in the world. Bitumen, a very heavy petroleum, is recovered from mined oil sands using warm water extraction followed by separation treatments to isolate the bitumen product. The high energy, water use, as well as tailings remediation challenges associated with the warm water extraction process raise major environmental concerns. Non-aqueous extraction using organic solvents at room temperature has been investigated extensively as an alternative to the warm water extraction process. The main challenge to the large-scale implementation of non-aqueous extraction is the retention of solvent in the tailings. The objective of this work was to present and validate a computational model for the interaction of solvents used in non-aqueous extraction with minerals, such as the abundant and adsorbent clay mineral kaolinite. The model system contained a periodically extended kaolinite platelet immersed in a solvent and all were treated at the atomic level using the 3D Reference Interaction Site Model with the Kovalenko-Hirata closure approximation (3D-RISM-KH) molecular theory of solvation. The solvent solvation free energy of interaction with kaolinite as well as site-specific adsorption energies and kinetic barriers for desorption were computed based on the solvent site density distribution functions. Moreover, the lateral and integrated density distributions were computed to analyze the organization of solvent at kaolinite surfaces. The integrated density distribution profiles were correlated with experimental adsorption isotherms. The results showed very strong adsorption of ethanol and weak adsorption of hydrocarbon solvents on kaolinite, which were in qualitative agreement with experimental solvent extraction reports. The model and these findings are valuable in understanding the mechanism of solvent retention in tailings after non-aqueous extraction and highlight the action of hydroxylated cosolvent additives to enhance extraction using nonpolar solvents.