The Çankırı Basin is one of the largest Cenozoic basins in Central Anatolia, Turkey and contains possible economic hydrocarbon and evaporite reserves. Gypsum is the dominant mineral in the evaporite-bearing Pliocene deposits of the Çankırı Basin. In claystones, the abundance of smectite, dolomite, illite/mica and chlorite in association with minor amounts of mixed-layer chlorite-smectite, mica-vermiculite, amphibole, serpentine, quartz and feldspar together indicate an alkaline environment. Minor kaolinite is also present in some clay samples. Smectite is both detrital and authigenic. Palynological analysis revealed the existence of a mixed forest (Pinus, Cathaya, Tsuga, Cedrus, Abies, Quercus, Ulmus, Juglans, Pterocarya, Acer, Carya, Carpinus, Fagus) dominated by Pinus with a widespread herbaceous understory (Poaceae) interspersed sparsely with open areas occupied by Asteraceae. This flora reflects warm-temperate and humid climatic condition. δ13C analyses have shown that the vegetation was dominated by C3 plants.

An experimental investigation was conducted on the alkali activation of a kaolinitic clay using an alkaline mixture composed of hydrated lime (Ca(OH)2) and sodium carbonate (Na2CO3) solution. The Ca(OH)2/Na2CO3 alkaline mixture was developed to overcome the high cost and chemical aggression associated with classical alkaline solutions. The mineralogical composition and microstructure of the alkaline mixture and alkali-activation products were studied using X-ray diffraction, attenuated total reflectance-Fourier transform infrared spectroscopy, thermogravimetric analysis and energy-dispersive X-ray-scanning electron microscopy techniques. Pirssonite (Na2Ca(CO3)2·2H2O), calcite (CaCO3), and sodium hydroxide (NaOH) formed as a result of mixing of Ca(OH)2 with Na2CO3. The alkali activation of natural clay with the Ca(OH)2/Na2CO3 alkaline mixture produced a binding agent identified as hydroxysodalite phase (Na8Al6Si6O24(OH)2·4H2O) when pure kaolinite was used, and cancrinite carbonate (Na6Ca1.5[Al6Si6O24](CO3)1.5·1.8H2O) when kaolinitic clay with high a calcite content was used. The mechanical strength of the binder developed was evaluated on cylindrical specimens containing granite waste as a filler material under dry and soaked conditions. The classical NaOH activator was used for comparison. For specimens produced using a Ca(OH)2/Na2CO3 mixture as the alkaline activator, the recorded strength valuewas 21 MPa which was 35% less than that achieved by the classical NaOH solution. Durability tests on samples soaked in water for 24 h showed a reduction in strength from 34 to 22 MPa for specimens prepared with NaOH solution, and from 21 to 11 MPa for the specimens prepared with a Ca(OH)2/Na2CO3 alkaline mixture.

Ultramarine pigments were synthesized successfully from Na-A zeolite derived from kaolin waste. Na-A zeolite encapsulates the sulfur species formed and which act as chromophores, which circumvents their oxidation and the subsequent liberation of high levels of toxic gases during the reaction. Different Na-A zeolite matrices with various grain sizes (fine to coarse) were mixed with sulfur and sodium carbonate in various proportions to study the influence of these variables on the pigments’ colours and hues. After calcination at 500°C for 5 h, the products were characterized by X-ray diffraction, X-ray fluorescence and Raman spectroscopy and were classified by the Munsell system (colour and hue). Products with colour ranging from blue to green with various hues were obtained. Both colour and hue were affected by the amount of additives and by the particle size.

Resonance energy transfer (RET) in hybrid polymer/inorganic/organic layers in saponite films, prepared using the ‘layer-by-layer’ (LBL) method, was studied. This method allows the fabrication of a multicomposite molecular assembly based on electrostatic and/or other intermolecular interactions between the interacting species. The LBL films were designed by sequential deposition including positively charged polycations ( poly(diallyldimethyl ammonium), PDDA) and negatively charged saponite dispersions with donor molecules (rhodamine 6G) and saponite dispersions with acceptor molecules (rhodamine 3B). In this sequence, the layer of saponite donor molecules was placed on an adjacent layer of saponite acceptor molecules, while the layers were separated by inserting a PDDA polycationic layer. The adsorption process was studied using absorption spectroscopy. The linear deposition regime was completed when ten layers had been deposited. The process of REF was studied by fluorescence spectroscopy. In this case the donor molecules – rhodamine 6G – play the role of lightharvesting antennae and transfer the energy to the next layer covered by energy acceptor, i.e. rhodamine 3B molecules. The insertion of polycation layers is rationalized by the adhesion of negatively charged underlying layers and the stabilization of multicomponent systems. The energy transfer efficiency was affected heavily by changing the distances between the adjacent layers.

The effect of ulexite concentrator waste on the physical and mechanical properties and sintering behaviour of a standard floor tiles (FT) body fired at 1080°C was studied. The linear firing shrinkage, water absorption and fired bending strength of the floor tile/tiles were determined. X-ray diffraction analyses identified quartz, albite, mullite and hematite phases in the floor tiles containing 3 wt.% waste material. The FT body with the smallest water absorption (∼0.2%), the greatest bending strength (∼335 kgf/cm2) and the second greatest linear firing shrinkage values had optimal composition. In light of the excellent physical-mechanical properties and the results of the scanning electron microscopy-energy dispersive X-ray analyses, the authors determined that the sintering temperature of the FT body containing 3 wt.% ulexite concentrator waste was reduced by 100°C.

The function of acid-activated sepiolite clay was evaluated for use in the clarification of apple juice. Optimizing the clarification process was done using response surface methodology (RSM) considering juice turbidity as a response. The efficiency of sepiolite in terms of clarification was compared to that of bentonite and a combination of these fining agents with gelatin and silica gel at optimal conditions. The conditions of 0.05% clay concentration at a temperature of 50°C for 7 h were deemed optimal in terms of juice clarification. The present results showed that treatment of sepiolitegelatin-silica gel was the most active fining agent with 99.7% reduction in apple-juice turbidity. The rate of turbidity, the viscosity, the total phenolic contents and the colour changes were fitted to first-, zero-, first- and zero-order kinetic models, respectively.

Ordovician clastic rocks of the Antalya unit in SW Turkey bear mineralogical/geochemical evidence of Triassic extensional rift timing and spatial relations. The crystal chemistry of the phyllosilicate assemblages (illite, chlorite, kaolinite, mixed-layer illite-smectite, chlorite-vermiculite and chlorite-smectite) is consistent with the rock experiencing a multi-generational burial history. The appearance of kaolinite and illite-smectite-bearing rocks in the Antalya unit is characteristic of diagenetic-anchimetamorphic conditions and is of higher grade than their anchi-epizonal equivalents in other regions of the Tauride belt. Illites and chlorites are of both detrital and authigenic origin, whereas I-S and kaolinites are authigenic. Detrital micas have been altered to chlorite and K-white mica stacks in which relicts suggest the chlorites were derived from detrital biotites. The broad X-ray diffraction illite peaks show that they are composed both of illite and illite-smectite. Na,K-mica and paragonite occur within the chlorite-mica stacks as replacements of muscovite, probably driven by Na-rich solutions. The authigenic clays were formed within the microporous matrix and the interplanar spaces of {001} planes of chlorite-mica stacks, with textures independent of the bedding and foliation planes of the rocks. The authigenic chlorites exhibit higher Si and Fe and lower Mg contents than their detrital counterparts. Authigenic chlorite thermometry indicates rift-related temperatures of 50–150°C, whereas pre-rift detrital chlorites formed at temperatures of  >200°C. Authigenic illite and illite-smectite are phengitic in composition and contain more Si, Mg, Fe and Ca and less Al and K than detrital K-white micas. The textural, mineralogical and chemical characteristics support the hypothesis that the mineral assemblages were a result of a two-step mode of formation with diagenetic overprints of previously anchizonal rocks in extensional basin conditions.

The Tremp–Isona basin (south-central Pyrenees, Lleida, Spain) shows maximum development of the Tremp Group (early Maastrichtian to late Paleocene) covering a wide geological record across the Cretaceous–Paleogene (K/Pg) boundary in continental facies. The mineralogy and geochemistry of lutites were used to assess the evolution of weathering from the Maastrichtian to the Eocene, and particularly for the red beds of the Lower Red and Upper Red Units (pre- and post-K/Pg, respectively). Chemical weathering decreased initially in the Maastrichtian (Gray Unit to Lower Red Unit), increasing subsequently from the Paleocene (Upper Red Unit) to Eocene units. ANOVA analysis of mineralogical compositions and cluster hierarchical analysis have been useful tools to select convenient lutites for assessment of weathering evolution by the chemical alteration index and by broadening of the 001 X-ray diffraction line of illite after ethylene glycol solvation. The lesser chemical weathering found in the Upper Red Unit (Danian) is interpreted in the context of relative warming and aridification, in climates of contrasting seasons and pronounced dry seasons.

Because of the current need for new landfill sites in Ankara, the suitability of Ankara Clay as a liner material for landfill sites was investigated. A mineralogical and geotechnical database was created by compiling the results of previous tests by the present authors as well as those of tests performed in the present study. The mineralogical properties of the samples were investigated by X-ray diffraction, scanning electron microscopy and methylene blue adsorption. The cation exchange capacities (CEC) of the samples vary from 12 to 35 meq/100 g soil and the dominant clay minerals are illite, smectite and kaolinite. The geotechnical properties of the Ankara Clay samples that were assessed included specific gravity, the Atterberg limits (plastic limit, liquid limit, plasticity index), particle-size distribution, compaction properties (i.e. maximum dry density and optimum water content) and hydraulic conductivity. Because the hydraulic conductivity of the samples was lower than the acceptable limit of 1 × 10−9 m/s, it follows that, from a geotechnical perspective, Ankara Clay is a suitable material for use as a compacted clay landfill liner. The relationships between the mineralogical and geotechnical parameters that were investigated by regression analysis indicated that the hydraulic conductivity of the compacted soil samples decreased with increasing plasticity index, clay content, CEC, smectite content, smectite to illite ratio and decreasing illite content. According to the specifications for field construction of compacted clay liners, Ankara Clay is suitable for compaction in the field.

The detection of the plastic limit of clays is subject to human error. Several attempts have been made to correlate across studies the geotechnical properties of fine-grained soils (water content, liquidity index, shear strength, etc.). Based on the premise that the liquidity index and water content ratio can be correlated directly, an alternative method to obtain indirectly the plastic limit is suggested here. The present study investigated 40 natural clayey samples of various mineralogies and origins and other publicly available data, where Atterberg limits and undrained shear strength values obtained with the vane shear tests were given. The liquidity index and water-content ratio correlate very well for defined undrained shear strength values of the clays. Solving the liquidity index equation for the plastic limit, estimated plastic limit values obtained by the liquidity index/water-content ratio relationship were compared with laboratory plastic-limit values. Preliminary results based on 62 values show an exponential trend with a multiple regression coefficient of 0.79. The data need to be confirmed on a larger database, however.

Porous clay heterostructures were prepared from Al-intercalated clays, and they allowed the insertion of Al into the framework of intercalated silica in porous clay heterostructures (PCHs). This method has led to tuneable Al contents within the resulting porous clay heterostructures. X-ray fluorescence confirmed the presence of Al in the intercalated precursors and their derivatives (porous clay heterostructure materials) in various environments, as indicated by 27Al magic-angle spinning nuclear magnetic resonance. The Al porous clay heterostructures exhibited specific surface areas that varied from 743 to 850 m2/g with total acid concentrations which varied from 0.969 to 1.420 mmol of protons/g of material, values which were deduced from the temperature desorption of cyclohexylamine. These acid sites were sufficiently strong to initiate the hydro-isomerization of n-heptane. The catalytic properties of the porous clay heterostructures depended on the Al contents and reached a maximum conversion rate of 50% and an isomer selectivity of 70% at a test reaction temperature of 350°C.

In many countries, compacted bentonite is a candidate engineering barrier material for safe disposal of high-level radioactive waste. The Swedish Nuclear Fuel and Waste Management Company (SKB) set up an in situ experiment (the ABM project) to compare the stability of different bentonites under the conditions of exposure to an iron source and to elevated temperature (up to 130°C) at the Äspö Hard Rock Laboratory, Sweden. Results for the Japanese bentonite (Kunigel V1) are summarized in the present study.

Mineralogical investigation using X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive X-ray spectroscopy (SEM-EDX) suggested no transformation of smectite or neoformed clay phases. However, a distinct change in exchangeable cations of smectite was indicated (i.e. from Na type to Fe type and/or Ca type) in the bentonite in the vicinity of the steel heater.

Measurements of hydraulic conductivity and swelling properties suggest that no significant changes occurred in the bentonite even in the vicinity of the steel heater. This is attributed to the limited portion of the bentonite affected by the iron–bentonite interactions and the incomplete ion-exchange reactions. The methylene blue cation exchange capacity and the determination of the exchangeable cations showed that the lateral distribution for these parameters was constant. However, the total exchangeable cation population has changed significantly compared to the initial sample.

The percolation of water through waste landfills produces leachates with high concentrations of which can generate -exchanged clays within geochemical barriers. These leachates also contain several volatile organic compounds (VOCs) which can interact with the clay barrier. The aim of the present study was to characterize the sorption of eight short-chain VOCs (acetonitrile, methyl tert-butyl ether, dichloromethane, benzene, phenol, ethanol, acetone and aniline) on -smectite, and to identify their sorption mechanisms. The samples treated were characterized by carbon and nitrogen elemental analysis, infrared spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. For acetonitrile, methyl tert-butyl ether, dichloromethane and benzene, no sorption was detected. Phenol, ethanol and acetone were sorbed very weakly, through Van der Waals interactions. Aniline molecules were sorbed strongly on -smectite mainly with hydrogen bonds between aniline and interlayer water molecules. However, aniline sorption decreased the hydrophilic character of the -smectite, which may increase the permeability of the clay barrier.