Diagenesis of the Sedimentary Fe–Ni Deposits of Euboea: Evidence Based on Phyllosilicate Mineralogy

A set of samples with different textures from the sedimentary Fe–Ni deposits of Central Euboea, Greece, were studied with XRD and SEM-EDS to investigate the relationships between phyllosilicates present. The deposits are characterized by the coexistence of smectite, corrensite, R0 mixed-layer chlorite-smectite and discrete chlorite, which indicates disequilibrium conditions. It is suggested that chlorite, the main Ni-host in the deposits, formed by conversion of smectite (nontronite and possibly stevensite), via corrensite and R0 Chl-Sme during diagenesis. This is the first report for chloritization of Fe-rich dioctahedral smectite during diagenesis.

Occurrence and significance of smectite in the Pliensbachian (Lower Jurassic) at Lókút (Bakony Mts., Hungary)

Although the Mesozoic rocks of the Transdanubian Range have been the subject of a multitude of different studies, mineralogical research is largely underrepresented. The clay mineralogy of Lower Jurassic (especially the Pliensbachian and Toarcian) strata was broadly investigated earlier; however, systematic high-resolution clay mineralogical studies remain scarce. Here we present a mineralogical study focusing on the Upper Pliensbachian strata of the Lókút-Hosszúárok section, located near the Eplény Manganese Ore Field. We identified dioctahedral smectite, randomly interstratified illite/smectite, illite as 10 Å phyllosilicate, quartz and cristobalite. Based on our new results we propose that the smectite was formed by aging of Mg or Fe hydroxide-silica precipitates. The smectite and cristobalite were presumably formed from the siliceous tests of radiolarians, whose abundance was controlled by a local upwelling system. The occurrence of Pliensbachian smectite in the Lókút outcrop shows similarities with the Úrkút smectites known from both Pliensbachian and Toarcian strata, which implies that similar processes controlled the sedimentation during the Pliensbachian as well as during the black (gray) shale-hosted ore accumulation in the Eplény and Úrkút basins.

Modification of Spent Bleaching Earth with WO3 and the Application for Photocatalytic Degradation of Waste Dyestuff under Solar Light

Degradation of blue dye waste in Sarong Samarinda production using WO3-bleaching earth (BE) has been conducted. Structural and morphological characterization has conducted using X-ray diffraction (XRD), and Scanning electron microscopy-energy dispersive spectroscopy (SEM-EDX). The X-ray diffraction results show the mineral on bleaching earth is rectorite dioctahedral mica layer and dioctahedral smectite with a ratio 2:1. The WO3 pattern is appeared after the calcination. After calcination at 500°C, the WO3 is deposited homogeneously on the BE surface. The catalytic performance of WO3-BE for photodegradation of the blue dye waste under the solar light is 99.85 % within 1 h.

Smectitization as a Trigger of Bacterially Mediated Mn-Fe Micronodule Generation in Felsic Glass (Livno-Tomislavgrad Paleolake, Bosnia and Herzegovina)

Miocene tuffs preserved in argillaceous sediment interbedded with lacustrine successions are commonly encountered throughout the Dinarides Lake System (DLS) in south-eastern Europe. In this contribution the volcanic glass degradation and co-genetic Mn-Fe precipitation were studied in a 14.68 Ma felsic tuff from DLS Livno-Tomislavgrad Basin. Microbial activity has been involved in both reactions thus adding the interest of revealing effects of biotic and abiotic processes taking place during tuff eogenesis. X-ray diffraction and electron microbeam analysis with energy-dispersive X-ray spectroscopy revealed the pitting or granular structures developed at glass rims along with smectite flakes protruding from a degrading glass. Mn-Fe mineralization emerges in the form of Mn-Fe coatings, an initial step to micronodule formation, where traces of biogenetic influence included a high content of phases rich in structural Mn (IV) (i.e., ranciéite and jacobsite) and presence of microbial microfossils. Co-genetic ties between glass degradation and Mn-Fe precipitation were established through the report of dioctahedral smectite formed out of altered glass; which then served as nuclei of the ongoing biotic and abiotic Mn-Fe mineralization. These processes manifest on a continuous involvement of microbial life in the course of eogenesis of pyroclastic material in lacustrine environments.

Mineralogy, Geochemistry and Genesis of Zeolites in Cenozoic Pyroclastic Flows from the Asuni Area (Central Sardinia, Italy)

Natural zeolite occurrences have been recognized in several Cenozoic pyroclastic deposits in central Sardinia. This study concerns the mineralogical and geochemical characterization of the zeolitized tuffites in the Asuni area (Oristano province) and aims to complement information regarding the zeolitization processes developed in the nearby Allai deposits. Optical and scanning electron microscopy, X-ray powder diffraction, qualitative vs. quantitative microanalyses and bulk-rock geochemistry were performed. Analytical results allow defining the mineral distribution, textural relationships and geochemical features of the zeolite-bearing rocks. The most abundant secondary minerals are Ca-Na mordenites. Contrarily to the most common worldwide clinoptilolite + mordenite paragenesis, mordenite is dominant and occurs in different morphologies, rarely coexisting with clinoptilolite in the studied volcanic tuffites. Glauconite and dioctahedral smectite complete the authigenic assemblages. The primary volcanic components mostly include plagioclase, quartz and glass shards, roughly retaining their original appearance. The tuffites range in composition from dacite to rhyolite. The collected dataset shows that zeolitization is most abundant in coarser-grained deposits and points to a genetic process that mainly involves an open hydrothermal environment governed by aqueous fluids with significant marine component, in post eruption conditions.

The Triple Mechanisms of Atenolol Adsorption on Ca-Montmorillonite: Implication in Pharmaceutical Wastewater Treatment

The adsorption of atenolol (AT) from aqueous solutions by Ca-montmorillonite (SAz-2) was investigated in batch studies under different physicochemical conditions. The AT existed in neutral un-dissociated form at pH 10, and was adsorbed on dioctahedral smectite (SAz-2) obeying the Langmuir isotherm with a maximum adsorption capacity of 330 mmol/kg. The kinetic adsorption suggested that both strong and weak adsorption sites existed on SAz-2 and participated in the adsorption mechanisms. The amount of exchangeable cations desorbed from SAz-2 during AT adsorption was linearly correlated with the amounts of adsorbed AT having slopes of 0.43, which implied that a cation exchange based adsorption mechanism was also in place. A comprehensive basal spacing change of SAz-2 was observed after AT adsorption on the clay mineral when tested with or without AT recrystallization. The intercalation of AT into the SAz-2 interlayers did not result in swelling due to the low adsorption capacity of the drug. Prominent interactions between the pharmaceutical molecule and SAz-2 were evidenced by apparent shifts of the infrared absorption bands after adsorption. The interlayer configurations and hydrogen bonding of AT on SAz-2 were also supported by infrared, X-ray diffraction and thermogravimetric analyses. This study suggested that SAz-2 is an excellent material to remove not only AT from pharmaceutical wastewater, but can potentially remove many other β-receptor blocker drugs. The results helped us to understand the possible interlayer configurations and adsorption mechanisms of the drugs on natural clay mineral based adsorbents.

USE OF SORPTION PROCESSES IN THE TECHNOLOGY OF DRUG DELIVERY SYSTEMS

The aimof this research is the review of scientific and technical literature regarding possibility of using sorption processes in the technology of drug delivery systems.Materials and methods. The materials are the following electronic resources: eLIBRARY, CyberLeninka, PubMed. The methods of review are analysis and synthesis. The study covers the scientific literature from 1996 up to the present time.Results.Sorbents are used as carriers for various medicinal peroral substances, they are also dispensers of various compounds in the form of polymeric eye films and stents in the human body. The delivery of medicinal substances occurs with the help of sorption processes of mass transfer. Currently, the following medical substances are used as carriers for medicinal substances: activated carbon, mineral sorbents (medical clays, synthetic sorbents), polymers and their biosimilars. 6 groups of pharmaceutical substances are registered for the production of enterosorbents in Russia and they can be used as sorbent carriers in the sorption drug system. They are: activated carbon, colloidal silicon dioxide, polyvinylpyrrolidone, dioctahedral smectite, polymethylsiloxane polyhydrate. As a result of the study, the model of the sorption drug system has been developed. It consists of sorbent carrier, active pharmaceutical ingredient and excipients that provide the desorption. Desorption of the active pharmaceutical ingredient may contribute to its modified release. The technology for obtaining sorption medicinal systems requires further study and development of modeling methods, searching for experimental pharmacological models and technological methods, which make it possible to obtain sorption dosage form with modified release.Conclusion.The review of the sorption processes used in the technology of drug delivery systems has been carried out. The model of the sorption drug system has been developed.