The increasing levels of industrial wastewater released to the environment present a serious threat to human health, living resources, and ecological systems. Fe-modified zeolites were developed and tested for removal of Cu2+ and Zn2+ from contaminated water. The surfaces of the naturally occurring zeolite, clinoptilolite, were modified with Fe(III) oxyhydroxides using three different methods, denoted I, II, and III (FeCli1, FeCli2, and FeNaCli1, respectively). The oxyhydroxides were prepared in Method I using 0.1 M FeCl3·6H2O in an acetate buffer (pH = 3.6); in Method II, using 10ai] FeCl3·6H2O solution in 0.1 M KOH (pH = 10); and Method III was the same as Method I except the clinoptilolite was pretreated with NaCl. Newly synthesized materials from these three methods were then tested for their ability to enhance the sorption capacity for Cu and Zn compared to the natural sample (Cli). Powder X-ray diffraction measurements and the chemical composition of these modified samples confirmed that clinoptilolite maintained its structure while amorphous Fe3+ species were synthesized. The specific surface area (BET method) of both the natural and modified clinoptilolite increased by 2 and 7.5 times for Methods I and II, respectively. Scanning electron microscopy and energy dispersive X-ray spectroscopy revealed that CaO was formed during Method I (FeClii). Throughout the adsorption process, the hydrolysis of CaO and the release of OH− caused the precipitation of Cu and Zn hydroxide, which made the determination of the sorption capacity of FeClii impossible. This phenomenon was avoided in Method III (FeNaClii) because of the absence of exchangeable Ca2+. The adsorption experiments with Method II resulted in double-enchanced adsoprtion capacity. Laboratory batch experiments revealed that the sorption capacities increased in the following order: Cli < FeCli2 < FeNaCli1, for Cu: 0.121 mmol/g < 0.251 mmol/g < 0.403 mmol/g and for Zn: 0.128 mmol/g < 0.234 mmol/g < 0.381 mmol/g.

The molecular aggregation of organic dyes onto clay mineral particles is a very complex phenomenon including dye adsorption, the migration of dye molecules, rearrangement of initially formed aggregates, etc. Some details of this complex process are not yet fully understood. The objective of the present study was to understand the influence of dye surface concentration on the dynamic processes in dye molecular aggregation. A stopped-flow rapid mixing device was used for accurate measurements of the molecular aggregation of the cationic dye rhodamine 123 (R123) in montmorillonite (MntK) colloidal dispersions. The influence of dye surface concentration, which was changed by altering the ratio of the amount of R123 to the mass of MntK (nR123/mMntK), was examined in detail. Chemometric analysis was used to reconstruct the spectral matrix to obtain linearly uncorrelated spectral profiles of the major components and their concentrations at the respective reaction times. The conversion of isolated R123 cations into oblique J-aggregates (head-to-tail molecular assemblies) was observed over time and the existence of a J-dimers intermediate was hypothesized. The reaction kinetics followed a biphasic exponential function. An unexpected effect of dye surface concentration on R123 aggregation was observed: the initial formation of the molecular aggregates increased significantly with dye surface concentration, but an inverse trend was observed after longer reaction times. While dye aggregates were formed slowly at low dye loadings, systems with high R123/MntK ratios (nR123/mMntK) reached spectral stability after the first few seconds of the reaction. After longer reaction times, the greatest degree of dye aggregation was achieved in the dispersion of the lowest dye loading. Such a phenomenon is described for the first time. The results presented here are important for understanding the complex processes occurring in systems based on organic cations and clay minerals, and should be considered in the development of functional hybrid materials of dyes and nanoparticles with a layered structure.

A hybrid of montmorillonite (Mnt) and rifampicin (RIF) was synthesized and the structure and stability of the drug carrier system clarified. Density functional theory calculations involving dispersion corrections (DFT-D3) were performed to characterize interactions acting in the interlayer space of montmorillonite intercalated with rifampicin. The structure and stability of the RIF-Mnt intercalated complex were determined. Calculations revealed the deformation of the molecular structure of rifampicin after intercalation into the Mnt interlayer space due to the clay environment. The ansa chain of RIF was bent in the interlayer space compared with the structure of the RIF molecule in the monocrystal. RIF was keyed into the Mnt surface by means of numerous hydrogen bonds of weak to moderate strength. The calculated vibrational spectrum from ab initio molecular dynamics (AIMD) was in good agreement with the FTIR measured spectra and helped to analyze the overlapped vibrational bands. Based on analysis of structural stability, theoretical calculations revealed that Mnt is a suitable drug carrier for delayed release of the RIF drug. Batch adsorption experiments showed the large adsorption capacity of montmorillonite for RIF.

Attempts at optical resolution and asymmetric syntheses using smectite clay minerals are described. Use of the method was prompted by the discovery that the saturated adsorption of a tris(chelated) metal complex, [Ru(1,10-phenanthroline)3]2+, by Na-montmorillonite depended heavily on the stereochemical properties. The pure enantiomer was adsorbed by cation exchange at negative surface sites of the clay mineral, while the racemic mixture was adsorbed to two times excess of the cation exchange capacity. The chelate takes a uniform orientation on a clay mineral surface due to the matching between the molecular symmetry and the two-dimensional network of a phyllosilicate layer. On a clay mineral surface covered with the enantiomeric chelates, a vacant space capable of chiral discrimination was generated. Based on this, an ion-exchange adduct of smectite and the chiral chelate was used as an adsorbent for separating racemic mixtures or selectively producing either one of the optical isomers.

Micromorphological studies were performed in order to understand the factors and processes involved in the formation of calcium carbonate (CaCO3) in twenty three soil series of Vertisols representing sub-humid, semi-arid and arid climatic regions of Peninsular India. The study indicates that Vertisols contain both pedogenic calcium carbonate (PC) and non-pedogenic calcium carbonate (NPC) irrespective of the ecosystems to which they belong. The NPCs are part of the parent material of Vertisols. Dissolution of NPCs and recrystallization of dissolved Ca2+ ions are responsible for the formation of PCs. Vertisols of arid and semi-arid climates contain more PC in their soil control section (SCS) than those of sub-humid climates. Formation of PC is the prime chemical reaction responsible for the increase in pH, the decrease in the Ca/Mg ratio of exchange site with depth and in the development of subsoil sodicity. Petrographic and scanning electron microscopic (SEM) examination of quartz, feldspars and micas indicate little or no alteration, discounting the possibile formation of smectite during Vertisol formation. X-ray diffraction (XRD) analysis of clays indicates that smectites of Vertisols are fairly well crystallized and do not show any sign of transformation except for hydroxy interlayering. The preservation of the crystallinity of smectite and the lack of transformation of primary minerals thus validate the hypothesis of positive entropy change during the formation of Vertisols.

The precise cause-effect relationship between CaCO3 of pedogenic and non-pedogenic origin, and exchangeable Mg, Na and Ca percentages (EMP, ESP and ECP) has been established in the study. This indicates that impoverishment of Ca2+ ions on the exchange sites of Vertisols needs to be controlled by rehabilitation methods that can replenish Ca2+ ions, and thus the study provides relevant information for future land resource management programmes not only on Vertisols of India but also on similar soils occurring elsewhere.

Among the many techniques used to remove toxic dyes from the environment, layered double hydroxides (LDH) are considered to be especially environmentally friendly, but, this quality may be altered by variations in the octahedral Mg/Al molar ratios in the LDH structure. The aim of the present study was to synthesize environmentally sound LDH for use as an economically viable sorbent for the adsorption of reactive brilliant orange X-GN. Layered double hydroxides with Mg/Al molar ratios of 2:1 and 4:1 were prepared by co-precipitation. The materials obtained were characterized by powder X-ray diffraction (XRD), Fourier-transform infrared (FTIR) spectroscopy, X-ray fluorescence spectroscopy (XRF), and surface-area analysis. Batch experiments were carried out to investigate the effects of contact time, pH, adsorbent dosage, and initial dye concentration on the adsorption behavior of the reactive brilliant orange X-GN by Mg-Al LDH. The results showed that the optimum pH value for dye adsorption was 3.0, at which the adsorption capacities of the reactive brilliant orange X-GN by the 2:1 LDH and the 4:1 LDH at 298 K were 79.370 mg/g and 83.343 mg/g, respectively. Further analysis of the dye-adsorption kinetics show that they fit the pseudo second-order model well. The adsorption equilibrium data showed that the Langmuir model provided better correlation of the equilibrium data than the Freundlich model. This result indicates that LDH provide specific homogeneous sites where monolayer dye adsorption occurs. The results of XRD and FTIR analyses of LDH before and after the dye adsorption demonstrated that the adsorption mechanisms were ion exchange and coulombic attraction.

A major issue for the oil sand industry is the settling of thin fine tailings (TFT) which are a byproduct of the oil sand extraction process. These tailings are deposited in large ponds and settling takes decades. The aim of the present study was to increase understanding of the role of specific ion types (monovalent/divalent) present in the water in flocculation behavior, and hence the settling of flotation fine tailings of the Athabasca oil sands (which consist predominantly of kaolinite). In this study, two series of measurements were conducted and compared: one with TFT and with varying pH and salinity, and another with kaolinite suspensions with varying pH, salinity, and volume fraction. The volume fraction of kaolinite and TFT used was in the range 0.01–1% volume fraction for any ionic strength or ion. In this range the electrophoretic mobility was constant indicating that there were no particle-particle interactions, a required condition for electrophoretic mobility measurements. Electrokinetic measurements were made as a function of concentration of salt added and pH. The flocculation behavior of both TFT and kaolinite can be linked to the electrokinetic mobility at high ionic strength. The electrophoretic mobility values and therefore the electrokinetic charge of the particles were smaller for divalent salt than for monovalent salt. As a consequence, both kaolinite and fine tailings should and do flocculate more quickly in the presence of a divalent electrolyte during settling-column experiments. The electrophoretic mobility of kaolinite and tailings in electrolytes containing a majority of monovalent ions (NaCl) decreased in absolute values with decreasing pH while their electrophoretic mobility in electrolytes containing a majority of divalent ions (MgCl2) did not depend on pH. The flocculation of the fine tailings in an electrolyte where divalent ions are predominant is therefore not expected to be influenced by pH.

The stable carbon isotope composition of CO2 occluded in the gibbsite structure is proposed as a potential atmospheric paleo-PCO2 proxy. Analysis of pedogenic gibbsite from a modern Ultisol in the Piedmont of Georgia, USA, was conducted to test the basis for this concept and to help constrain the parameters used to describe physical and biological processes affecting such factors as the respiration rate of CO2. Co-variation of the δ13C and δ18O values with depth along a gradient parallel to the mixing line between the atmosphere and the soil organic material implies that diffusion is the process that determines the stable isotope composition of soil CO2. In the upper 40 cm, the measured δ13C values are not consistent with the expected diffusive depth profile assumed in paleo-PCO2 models. The isotope signature is reset downward in the depth profile with a concentration of the most atmosphere-like δ13C and δ18O values occurring at the top of the Bt horizon by some as-yet-unknown process. Bioturbation, recrystallization, and physical translocation are potential explanations for this observation. Regardless of the process at work, the net effect is an apparent two-component mixing curve between the top of the Bt horizon and deep within the saprolite. In cases where the A horizon is eroded but the Bt horizon is preserved it is possible that δ13C values of gibbsite-occluded CO2 can serve as a proxy for atmospheric paleo-PCO2. Careful textural study of all paleosols is therefore essential to match stable carbon isotope signatures with the horizons preserved. Understanding of modern dynamics and preservation of these isotopic signatures may also be important for those that employ other carbonate proxies.

The results from mesoscale simulations of the formation and evolution of microstructure for assemblies of Na-smectite particles based on assumed size distributions of individual clay platelets are presented here. The analyses predicted particle arrangements and aggregation (i.e. platelets linked in face—face configurations) and are used to link geometric properties of the microstructure and mechanical properties of the particle assemblies. Interactions between individual ellipsoidal clay platelets are represented using the Gay-Berne potential based on atomistic simulations of the free energy between two Na-smectite clay-platelets in liquid water, following a novel coarse-graining method developed previously. The current study describes the geometric (aggregate thickness, orientation, and porosity) and elastic properties in the ‘jammed states’ from the mesoscale simulations for selected ranges of clay particle sizes and confining pressures. The thickness of clay aggregates for monodisperse assemblies increases (with average stack thickness consisting of n = 3–8 platelets) with the diameter of the individualclay platelets and with the level of confining pressure. Aggregates break down at high confining pressures (50–300 atm) due to slippage between the platelets. Polydisperse simulations generate smaller aggregates (n = 2) and show much smaller effects of confining pressure. All assemblies show increased order with confining pressure, implying more anisotropic microstructure. The mesoscale simulations are also in good agreement with macroscopic compression behavior measured in conventional 1-D laboratory compression tests. The mesoscale assemblies exhibit cubic symmetry in elastic properties. The results for larger platelets (D = 1000 Å) are in good agreement with nano-indentation measurements on natural clays and shale samples.

A collection of green earths belonging to traditional artists’ pigments was examined in terms of mineralogy and provenance. The studied specimens included both mineralogical reference compounds and selected commercially available artists’ pigments, and contained green micas (glauconite or celadonite), chlorite, or smectite as pigmenting agents. The samples were examined by X-ray diffraction, Mössbauer spectroscopy, infrared (IR) spectroscopy, ultraviolet-visible (UV-Vis)-near-IR diffuse-reflectance spectroscopy and voltammetry of microparticles. Particular attention was paid to the Kadaň green earth, mined until the 20th century in the West Bohemia deposit. The Greene-Kelly charge-reduction test, detailed description of non-basal diffraction patterns and characteristic vibrations in the mid-IR spectra were used to classify the major pigmenting agent of the Kadaň green earth as ferruginous smectite with separately diffracting saponite-like clusters. The smectite contains ∼15% Fe, mainly in the trivalent form, a detectable fraction of Fe in tetrahedral sites, and it is accompanied by a significant amount of Ti-bearing relict minerals due to its volcanogenic origin. On the contrary, in green micas (glauconite and celadonite) the Ti content is much smaller. Diffuse reflectance spectroscopy was found suitable for distinguishing Fe as a constituent of free Fe oxides from Fe in the clay structure. It was also found to be useful for discriminating between green micas and smectites.

Hydroxymetal-clay complexes, which contain reactive surface hydroxyl groups, have a strong affinity for both heavy-metal cations and oxyanions and hence can serve as efficient sorbents for ionic contaminants. The co-sorptive behavior of heavy-metal cations and oxyanions on the surface of hydroxymetal-clay complexes is not well understood, however. The objective of the present investigation was to help bridge that gap by determining the feasibility of co-sorbing Cd cations and phosphate from aqueous solution to a hydroxyiron-montmorillonite complex (HyFe-mont). A montmorillonite-rich clay from Inner Mongolia, China, was the starting material. The results showed that Cd and phosphate could be sorbed, simultaneously and synergistically, to HyFe-mont without a change in solution pH. Similarly, when phosphate was sorbed before Cd, the sorption capacities were comparable to those obtained in the simultaneous sorption experiment, and the solution pH did not change.When Cd was pre-sorbed, however, the subsequent sorption of both Cd and phosphate decreased as did solution pH. X-ray photoelectron spectroscopy (XPS) indicated that the binding energies of P2p, Cd3/2, and Cd5/2 were of similar magnitude for both the simultaneous sorption system and the phosphate pre-sorbed system. In addition, the single Cd and Cd pre-sorbed systems had similar Cd3/2 and Cd5/2 binding energies. The combined sorption and XPS results suggested that sorbed phosphate and Cd formed P-bridged ternary complexes on the HyFe-mont surface, contributing to the synergistic uptake of the contaminants in the simultaneous sorption system.

This essay inquires whether digitally transformed work can be virtuous and under what conditions. It eschews technological determinism in both utopian and dystopian versions, opting for the premise of free human agency. This work is distinctive in adopting an actor-centric and explicitly ethical analysis based on neo-Aristotelian, Catholic social teaching (CST), and MacIntyrean teachings on the virtues. Beginning with an analysis of digital disruption, it identifies the most salient human advantages vis-à-vis technology in digitally transformed work and provides philosophical anthropological explanations for each. It also looks into external, organizational characteristics on both the macro and the micro levels of digitally transformed work, underscoring their ambivalence (efficiency and profits vs. exclusion and exploitation, flexibility and freedom vs. standardization and dependency) and the need to mitigate their polarizing effects for the sake of shared flourishing. The article presents standards for virtuous work according to neo-Aristotelian, CST, and MacIntyrean frames and applies them to digitally transformed work, giving rise to five fundamental principles. These basic guidelines indicate, on one hand, actions to be avoided and, on the other, actions to be pursued, together with their rationales.

The early stages of amphibole weathering result in the crystallization of several clay mineral species: tri- and dioctahedral smectites, interstratified dioctahedral kaolinite-smectite (K-S), and halloysite. Each clay mineral crystallizes into specific microsites which develop from etch pits along specific crystallographic directions in the host amphibole. Two types of microsites are recognized according to their location in the amphibole crystal and their clay mineral crystallizations. The first type is a plane surface related to the (110) amphibole cleavages where saponite particles crystallize in a characteristic honeycomb texture. The second type is a ‘sawtooth’ (001) fracture surface generated by etch-pit coalescence where (1) platy K-S particles crystallize directly in contact with the amphibole at the top of ‘teeth’, (2) halloysite particles with tubular habits crystallize directly in contact with the amphibole on the side of the ‘teeth’, and/or on the K-S particles, and (3) montmorillonite crystallizes in the central part of the (001) fracture as a layer with honeycomb texture in contact with the K-S platelets located at the top of ‘teeth’. The microtextural relationships between the clay minerals and their host mineral suggest the following crystallization sequence: (1) saponite and montmorillonite crystallize first on the (110) and (001) surfaces, respectively; (2) as amphibole dissolution proceeds perpendicular to the (001) fracture planes, montmorillonites continue to form in the middle part of the widening fracture whereas K-S crystallizes on the ‘sawtooth’ termination; (3) in the last stage of weathering, tubular halloysite crystallizes on the side of the ‘teeth’, and/or on the K-S.

Hybrid films consisting of Sumecton SA smectite (SSA) and a diacetylenic two-photon absorptive dye; 1,4-bis(2,5-dimethoxy-4-{2-[4-(N-methyl)pyridinium]ethenyl}phenyl) butadiyne triflate (MPPBT) were fabricated. The MPPBT-clay composites were prepared by the cation exchange method in a dimethylsulfoxide (DMSO)-water mixed solvent. A low-light-scattering film, suitable for use in optical devices, was obtained by filtration of the dispersion of the MPPBT-clay composites. Estimation of the two-photon absorption cross-section (σ(2)) by means of the open-aperture Z-scan technique was performed using the present film. The σ(2) value of MPPBT in the film fabricated at the MPPBT loading levels vs. 20% cation exchange capacity was 1030 GM (1 GM= 1 × 1050 cm4 s photon−1 molecule−1) at an excitation wavelength of 800 nm. The value was 1.3 times greater than the maximum value of the σ(2) of MPPBT diss lved in DMSO with ut clay.

A number of different types of bentonite deposits formed by hydrothermal alteration and diagenetic processes are to be found in the Ordu area of the Eastern Black Sea region. The Ca- and Na-bentonite deposits are related to Upper Cretaceous tholeitic to calc-alkaline volcanites, predominantly dacite and andesite, and also include rhyodacite with lesser basalt and their pyroclastic equivalents. In the present study, dacite (PR1), perlite (PR2), moderately altered rocks (MPR), and Na- and Ca-bentonites were studied to describe and compare their mineralogical and geochemical properties and their conditions of formation by means of X-ray diffraction, optical microscopy, scanning electron microscopy, and chemical analytical techniques.

Ca-bentonites, except for smectite, contain opal-CT, feldspar, biotite, and rarely pyrite, while Na-bentonites contain smectite and less feldspar, opal-CT, kaolinite, and illite.

Progressive alteration of the PR2 caused depletion in K2O and Na2O and enrichment in MgO and CaO in all of the Ca-bentonite samples. Na2O was depleted in all of the Na-bentonites and in most of the MPR. The medium and heavy rare earth elements (MREE and HREE) show mass gain or mass loss in the Na-bentonites. The HREE show nearly immobile behavior in the Ca-bentonites. The rare earth elements (REE) and transition elements (TRE) mostly gained mass in the Ca-bentonites in contrast to Na-bentonites. Large-ion lithophile elements (LILE) are strongly depleted in all of the bentonites. The LREE, MREE, and HREE were strongly depleted in most of the MPR samples. TiO2, Lu, Tm, and Tb show immobile behavior in all samples.

PR1 exhibits a slightly positive Eu anomaly. Two MPR samples show slightly positive Eu anomalies (1.03, 1.13), and one Na-bentonite sample displays a slightly positive Eu anomaly (1.04). Most of the Nabentonites have weakly negative Eu anomalies, whereas perlite and the Ca-bentonite have a strongly negative Eu anomaly. The PR1, PR2, MPR, and Na-bentonite present a positive Ce anomaly, and the Ca-bentonite shows a moderately negative Ce anomaly. The Ca-montmorillonites are mainly hydrothermal in origin and derived from alteration of volcanoclastic material in situ and/or in the subaerial environment. The Na-montmorillonites formed by alteration and diagenesis of volcanoclastic material in the sedimentary basin.

The long, continuous deposition of dust in the Chinese loess plateau offers a unique opportunity to study the nature of Fe oxide formation in a wide range of climatic conditions. A technique to obtain quantitative estimates of the concentration of hematite and goethite in loess and paleosol samples is reported. Experiments using diffuse reflectance spectroscopy on sets of laboratory mixed and natural loess and paleosol samples show that it is possible to obtain rapid and quantitative estimates of the absolute concentration of hematite and goethite in the Chinese loess sediments. Typical loess and paleosol samples were deferrated using the CBD procedure to produce a natural matrix material to which hematite and goethite in known weight percentages were added to produce a set of calibration standards. Spectral violet, blue, green, yellow, orange, red and brightness of standards were calculated from the reflectance data and served as independent variables for a multiple linear regression analysis. The effect of changing matrix from loess to paleosol was overcome by including a variety of different loess and paleosol samples in the regression equations. The resulting calibration equations provide estimates of wt.% hematite and goethite and have correlation coefficients >0.93. The total measured hematite and goethite concentrations exhibited consistent variations with CBD extractable iron. Tests of the equations for buffering changes in matrix composition were run with samples of varying mineralogical composition (calcite, illite, etc.) and demonstrated that the equations are well buffered for changes in matrix composition from loess to paleosol.

Hydrophobicity, high viscosity, and dispersion are important properties for organo-montmorillonites, and all organo-montmorillonite configurations have yet to be fully characterized with respect to this property. High-viscosity montmorillonite (Mnt) is useful in gels and as an adsorber. The current study focused on modifying Mnt using organic cations and anions of various chain lengths in batch experiments with various concentrations and ratios. The viscosity of organic Mnt reached up to 395 mP.s. Molecular dynamics simulations and X-ray diffraction (XRD) were used to identify the conditions and arrangement of organic cations and anions in the Mnt interlayer area. The intercalation mechanism of organic cations and anions was also determined, providing a theoretical basis for the preparation of high-viscosity Mnt.