Several studies have been performed so far for the effective recovery, detection and quantification of specific compounds and their degradation products in archaeological materials. According to the ...literature, lipid molecules are the most durable and widespread biomarkers in ancient pottery. Artificial ageing studies to simulate lipid alterations over time have been reported. In this review, specific lipid archaeological biomarkers and well-established sampling and extraction methodologies are discussed. Although suitable analytical techniques have unraveled archaeological questions, some issues remain open such as the need to introduce innovative and miniaturized protocols to avoid extractions with organic solvents, which are often laborious and non-environmentally friendly.
The binding ability of five bifunctional 3-hydroxy-4-pyridinones towards Cu
and Fe
was studied by means of potentiometric and UV-Vis spectrophotometric measurements carried out at
= 0.15 mol L
in ...NaCl
= 298.15 K and 310.15 K. The data treatments allowed us to determine speciation schemes featured by metal-ligand species with different stoichiometry and stability, owing to the various functional groups present in the 3-hydroxy-4-pyridinones structures, which could potentially participate in the metal complexation, and in the Cu
and Fe
behaviour in aqueous solution. Furthermore, the sequestering ability and metal chelating affinity of the ligands were investigated by the determination of p
and pM parameters at different pH conditions. Finally, a comparison between the Cu
and Fe
/3-hydroxy-4-pyridinones data herein presented with those already reported in the literature on the interaction of Zn
and Al
with the same ligands showed that, from the thermodynamic point of view, the 3-hydroxy-4-pyridinones are particularly selective towards Fe
and could therefore be considered promising iron-chelating agents, also avoiding the possibility of competition, and eventually the depletion, of essential metal cations of biological and environmental relevance, such as Cu
and Zn
.
The thermodynamics of the interaction of L-glutamic-N,N-diacetic acid (GLDA) with protons was studied potentiometrically at different temperatures, ionic strengths and ionic media. Four protonation ...constants and corresponding enthalpy changes occurred at infinite dilution together with temperature and ionic strength coefficients. The medium effect was also interpreted in terms of the formation of weak complexes between the ligand and the cations of supporting electrolytes, resulting in a greater tendency of GLDA to chemically interact with Na+ rather than K+ and, in turn, (CH3)4N+. Formation constants of GLDA with Cd2+ were determined in NaCl(aq) at different ionic strength values. Five complex species were found, namely CdL2−, CdHL−, CdH2L0(aq), Cd2L0(aq), and Cd(OH)L3−, whose formation constant values at infinite dilution were log β = 12.68, 17.61, 20.76, 17.52, and 1.77, respectively. All the species results were relevant in the pH range of natural waters, although the Cd2L0(aq) was observed only for CCd ≥ CGLDA and concentrations of >0.1 mmol dm−3. The sequestering ability of GLDA toward Cd2+, evaluated by means of pL0.5, was maximum at pH~10, whereas the presence of a chloride containing a supporting electrolyte exerted a negative effect. Among new generation biodegradable ligands, GLDA was the most efficient in Cd2+ sequestration.
This work is focused on the design and preparation of polymer inclusion membranes (PIMs) for potential applications for stannous cation sequestration from water. For this purpose, the membranes have ...been synthesized employing two polymeric matrices, namely, polyvinylchloride (PVC) and cellulose triacetate (CTA), properly enriched with different plasticizers. The novelty here proposed relies on the modification of the cited PIMs by selected extractants expected to interact with the target cation in the membrane bulk or onto its surface, as well as in the evaluation of their performances in the sequestration of tin(II) in solution through chemometric tools. The composition of both the membrane and the solution for each trial was selected by means of a D-Optimal Experimental Design. The samples such prepared were characterized by means of TG-DTA, DSC, and static contact angles investigations; their mechanical properties were studied in terms of tensile strength and elastic modulus, whereas their morphology was checked by SEM. The sequestering ability of the PIMs toward stannous cation was studied by means of kinetic and isotherm experiments using DP-ASV. The presence of tin in the membranes after the sequestration tests was ascertained by μ-ED-XRF mapping on selected samples.
Biofouling has destructive effects on shipping and leisure vessels, thus producing severe problems for marine and naval sectors due to corrosion with consequent elevated fuel consumption and higher ...maintenance costs. The development of anti-fouling or fouling release coatings creates deterrent surfaces that prevent the initial settlement of microorganisms. In this regard, new silica-based materials were prepared using two alkoxysilane cross-linkers containing epoxy and amine groups (i.e., 3-Glycidyloxypropyltrimethoxysilane and 3-aminopropyltriethoxysilane, respectively), in combination with two functional fluoro-silane (i.e., 3,3,3-trifluoropropyl-trimethoxysilane and glycidyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononylether) featuring well-known hydro repellent and anti-corrosion properties. As a matter of fact, the co-condensation of alkoxysilane featuring epoxide and amine ends, also mixed with two opportune long chain and short chain perfluorosilane precursors, allows getting stable amphiphilic, non-toxic, fouling release coatings. The sol–gel mixtures on coated glass slides were fully characterized by FT-IR spectroscopy, while the morphology was studied by scanning electron microscopy (SEM), and atomic force microscopy (AFM). The fouling release properties were evaluated through tests on treated glass slides in different microbial suspensions in seawater-based mediums and in seawater natural microcosms. The developed fluorinated coatings show suitable antimicrobial activities and low adhesive properties; no biocidal effects were observed for the microorganisms (bacteria).
A series of new polyhedral oligomeric silsesquioxane ionic liquids (POSS‐ILs) based on the trimethylpropylammonium hepta(isooctyl)octasilsesquioxane cation and a variety of anions have been ...synthesized and characterized. Their thermal behavior has been ascertained by thermogravimetric and differential thermal analyses and differential scanning calorimetry; room temperature conductivity, dielectric constants, and dynamic contact angles have been investigated as well. The obtained data show that the presence of the POSS moiety is responsible not only for their thermal properties, but also for their low room‐temperature conductivity and dielectric constants, which, conversely, display slight differences originating from the nature of the anions. The long alkyl‐chain substituents on the POSS core infer on this series of ILs an overall hydrophobic character and solution properties comparable to those of classic cationic surfactants, resulting in an effective extractant capability of polyanions from aqueous solutions. Their solution diffusion properties, as investigated by room‐temperature dynamic light scattering, solution conductivity, density, and osmometric measurements, do not provide evidence for the occurrence of any significant self‐assembling processes.
A new family of organic/inorganic hybrid polyhedral oligomeric silsesquioxane (POSS) ionic liquids is reported. Their bulk and solution properties are dependent on the nature of the cation.
The archaeological excavations at Villa San Pancrazio (Taormina, Italy) are bringing to light a vast Roman-Imperial residential quarter featuring luxurious dwellings decorated with wall paintings and ...mosaic floors, pointing it out as one of the most significant archaeological sites of the city. The polychrome and black and white mosaics recovered date back to the middle Imperial period, during the 2nd century AD. This work deals with the first archaeometric investigations of the materials employed for the tesserae production with the aim of elucidating the mineralogical composition and obtaining analytical evidence that can contribute to extracting information related to their production technology. For that purpose, a non-invasive methodology, based on micro energy dispersive X-ray fluorescence (μ-EDXRF) spectrometry and Raman spectroscopy, was used to characterize a wide selection of stone, ceramic and glass tesserae. Chemometric tools were exploited to manage the large set of elemental data collected on black and white lithic samples, providing essential clues for the subsequent investigations. The results evidenced the employment of natural lithotypes (calcareous sedimentary, dolomitic and volcanic) local and imported, and also artificial materials, such as ceramic made firing magnesium-rich clays, soda-lime-silica glasses made with different opacifying and coloring agents (such as calcium antimoniate, cobalt and copper).
New star‐shaped quaternary ammonium (QA) polyhedral oligomeric silsesquioxane (POSS) salts based on octakis(tetraalkylammonium) POSS cations bearing alkyl chains of different length (methyl, n‐butyl, ...and n‐octyl) and differently polarizable anions iodide, bis(trifluoromethylsulfonyl)imide, and ibuprofen have been synthesized and characterized. Differential scanning calorimetry (DSC) and thermogravimetric analysis (TGA) investigations show that the nature of the cation plays a key role in determining the thermal behavior of QA POSS salts featuring the longest alkyl chains, whereas the influence exerted by anions becomes relevant for those bearing short and medium alkyl chains. All the QA POSS salts display amorphous behavior and, with the exception of octakis(trimethylpropylammonium)‐ and octakis(tri‐n‐butylpropylammonium)octasilsesquioxane iodide, may be classified as ionic liquids. Dynamic contact‐angle studies reveal their hydrophilic attitude owing to the preferential orientation of the tetraalkylammonium groups at the film–water interface.
Star‐shaped quaternary alkylammonium polyhedral oligomeric silsesquioxane (POSS) salts featuring various alkylammonium chain lengths and differently polarizable anions have been synthesized and characterized. Their ionic liquid behavior as a function of the cation–anion couples is reported.
The potential of pyrene-1-sulfonate to act as an emitting anion for the development of ionic liquids is explored here. Amphiphilic trimethylpropylammonium hepta(isooctyl)octasilsesquioxane and ...conventional imidazolium, namely, 1-vinyl-3-hexyl-, 1-vinyl-3-decyl-, and 1-methyl-3-decyl-imidazolium, featuring moderate alkyl chain length substituents, have been chosen as countercations. The new species have been synthesized via simple metathesis reactions involving pyrene-1-sulfonate sodium salt and the appropriate halide cation precursors. Their thermal behavior has been investigated by thermogravimetric and differential scanning calorimetry at different scanning rates. According to this latter technique, only the trimethylpropylammonium hepta(isooctyl)octasilsesquioxane pyrenesulfonate adduct, displaying a reversible glass transition at −4.2 °C, may be classified as an ionic liquid. All pyrene-1-sulfonate imidazolium-based ion pairs are crystalline solids with the melting point just above 100 °C that produce very complex, nonreversible, and scanning rate-dependent thermograms, very likely arising from polymorphism phenomena. Such a behavior may be attributed to the pyrene-1-sulfonate polycyclic system, which in solution, as confirmed through spectroscopic characterization, displays a general attitude in promoting supramolecular structures via cation interactions. Emission lifetime measurements on the emitting fluorophore reveal that there are at least two different active species, whereas light scattering measurements show the presence of aggregates with hydrodynamic radii depending on the medium and adduct concentration. Tests aimed at investigating the potential of these novel pyrene-1-sulfonate salts in functionalization/exfoliation of graphite flakes are also reported here.
New products to be employed as coatings for construction materials have been synthesized. Room temperature blending of poly(bisphenolA-co-epichlorohydrin), glycidyl endcapped (DGEBA) and ...3-aminopropyl-methyldiethoxysilane (AMTS), as well as of DGEBA, (3-glycidyloxypropyl)trimethoxysilane (GLYTS) and AMTS, in CHCl₃, employing different stoichiometric ratios, leads to transparent and crack free solids. The extent of epoxy cleavage during the hardening reaction and the hydrolysis of the Si(OR)x groups have been followed by ¹³C NMR spectroscopy in solution; the solids have been characterized by means of Raman, FTIR, and TG-DTA studies. The hydrophobic properties of the resulting solids have been investigated by contact angle measurements on coated glass slides, and have been tailored by adding to the above mixtures two fluorine-containing comonomers, namely glycidyl-2,2,3,3,4,4,5,5,6,6,7,7,8,8,9,9-hexadecafluorononyl ether (GLY16F) and 3,3,3-trifluoropropyl-trimethoxysilane (TFP-TMS). Preliminary tests to evaluate the efficacy of the above products, as construction materials coatings, have been carried out by means of mercury intrusion porosimetry and water absorption by the wicking method.
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