Effects of processing on the mineralogy and solubility of carbonate-rich clays for alkaline activation purpose: mechanical, thermal activation in red/ox atmosphere and their combination

The present study focuses on the assessment of the effects of different activation methods on carbonate-rich clays, to understand the mineralogical differences originated and to exploit such information to industry for traditional and innovative applications, especially as a precursor for alkali activated binders. Illite carbonate-rich clay samples were subjected to thermal activation in ox/red atmosphere between 400 and 900 °C, mechanical activation (grinding for 5, 10 and 15 min) and to a combination of such treatments. Mineralogical and textural changes in the activated samples were evaluated through X-ray powder diffraction, Fourier transform infrared spectroscopy and thermal techniques. The activated samples with the highest content of amorphous phase underwent leaching tests in a 3 M NaOH solution by means of inductively coupled plasma-mass spectrometry. The application of the three processing routines, yielded three types of activated clays with different leaching modes of Si, Al, K and Ca: (1) high energy grinding preferentially delaminates clay minerals and reduces the grain size of calcite. K leaching reaches the highest values; (2) thermal heating at 800 °C increases relatively the Si/Al solubility ratio, but the absolute concentrations of these elements are equal or lower than those obtained from ground clays. The relatively higher leaching of Ca is influenced by the formation of non-stoichiometric and poorly crystalline Ca-silicates and -aluminosilicates; (3) high energy grinding combined with heating treatment yields an extended amorphisation, mainly at the expense of clay minerals, with the highest leaching of Si and Al, and the lowest of Ca. New formed K-feldspars inhibit the concentration of K in alkaline solution

Multi-spectroscopic approach to explore the technological features of medieval gilded and enamelled glasses from Melfi (PZ)

Gilded and enamelled glasses of Islamic style, coming from a 13th century landfill in Melfi castle, a Swabian emperor Frederick II fortress, were subjected to a multi-techniques approach in order to explore the complex and very fascinating ancient production technology of gilding and enamelling on glass. Non-destructive μ-Raman spectroscopy was employed on the most important and well-preserved objects, optical (OM) and electron (SEM) microscopies were used to investigate the sections stratigraphy of tiny fragments sampled from the borders of the already damaged objects. In order to provide the chemical analyses of the bodies and the enamels, energy dispersive X-rays spectroscopy (EDS) and X-rays photoelectron spectroscopy (XPS) were also employed. The body of the objects proved to be made of silica-soda-lime glass, while the enamels of lead-rich glass (“soft enamels”) and coloured by lapis lazuli and cobalt for blue, hematite and minium for red, lead-tin yellow for green and calcium phosphate for white. The gilding was found to be applied on a red enamel basis. The presence of carbon inside the gildings and the detection of two different gold signals by XPS suggested the hypothesis of the use of the so-called “liquid gold”. This study gave thus an important contribution to the understanding of the production of this class of rare and precious objects, also confirming that the materials and technological procedures are consistent with the Islamic tradition, probably due to the presence of Islamic artisans at the court of Frederick II

An analytical techniques pool to hit the target. A comprehensive examination on an Apulian red figured pottery collection

No abstract availabl

An Innovative, easily fabricated, silver nanoparticles-based titanium implant coating: development and characterization

Microbial colonization and biofilm formation on implanted devices represent an important complication in orthopaedic and dental surgery and may result in implant failure. Controlled release of antibacterial agents directly at the implant site may represent an effective approach to treat these chronic complications. Resistance to conventional antibiotics by pathogenic bacteria has emerged in recent years as a major problem of public health. In order to overcome this problem, non-conventional antimicrobial agents have been under investigation. In this study, polyacrylate-based hydrogel thin coatings have been electrosynthesised on titanium substrates starting from poly(ethylene glycol diacrylate)–co– acrylic acid. Silver nanoparticles (AgNPs) with a narrow size distribution have been synthesized using a “green” procedure and immobilized on Ti implant surfaces exploiting hydrogel coatings’ swelling capabilities. The coatings have been characterized by XPS and SEM/EDX, while their silver release performances have been monitored by ICP–MS. The antibacterial activity of these AgNP-modified hydrogel coatings was tested evaluating in vitro inhibition growth of Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli, among the most common pathogens in orthopaedic infections. Moreover, a preliminary investigation of the biocompatibility of silver-loaded coatings versus MG63 human osteoblast-like cells has been performed. An important point of strength of this paper, in fact, is the concern about the effect of silver species on the surrounding cell system in implanted medical devices. Silver ion release has been properly tuned in order to assure antibacterial activity while preserving osteoblasts’ respons

RIvestimenti musivi di Ercolano. Indagine archeometrica su tessere

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