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From the Pioneer Era of the aviation to World War I the evolution of aircraft technology and chemical synthesis enabled a unique coexistence of traditional craftsmanship, artistic decoration practices, and technological advancements. The study of the materials used in these early years of aviation is still an uncharted territory: a vast portion of remaining planes has been partially or completely repaired and restored, usually by total replacement of the fabric. The Italian biplane Ansaldo A.1 (1918) is a fighter aircraft and is one of the few planes in the world that still preserves its own original materials. In the last years, the fabric sections of the airplane have started to become brittle and loose cohesion, severely compromising the integrity of the aircraft, and resulting in a general alteration of the pictorial layers of the painted sections. A chemical investigation was undertaken to unveil the materials, and to elucidate the causes of the degradation. This study presents one of the first steps into the study of early historical aircrafts, defining the background for the conservation plans to preserve these objects for future generations. [ABSTRACT FROM AUTHOR]

We developed a methodology for the cost optimization of electrokinetic treatment porous media contaminated by toxic metals. A two-dimensional reactive-transport model was implemented to simulate the transport of chemical species by diffusion, electromigration and electroosmosis, coupled with a geochemical model which calculates precipitation and dissolution of species, adsorption and desorption reactions, and aqueous speciation. The model was applied to the case study of an electrokinetic remediation prototype plant built in Livorno (Italy), treating 150 m 3 of dredged sediments contaminated by toxic metals. The plant consisted of an ex-situ treatment basin equipped with electrodic wells arranged on a rectangular grid, connected to an electrolyte management system for catholyte and anolyte pH control. We validated the model by comparing the simulated electric field with the measured electric potential and the simulated pH profiles with the pH values of field samples. Good agreement was achieved between the modelled and measured data. On the basis of the validated model, we performed a parametric study to evaluate the influence of electrode distance and sediment buffering capacity on treatment costs and calculated the overall cost as a function of these two parameters. The results and costs were evaluated in terms of Pb removal, which was taken as the representative toxic metal. The results revealed the existence of distinct minima, representing the best set of parameters which optimized the overall treatment costs. We believe that the methodology and results obtained can be employed as a valuable tool to support the evaluation and design of electrokinetic remediation systems. [ABSTRACT FROM AUTHOR]

In this paper we investigated the presence of Polycyclic Aromatic Hydrocarbons and Polychlorobiphenyls in a 50-m deep snow/firn core collected at the peripheral site GV7 in East Antarctica during the 2013–2014 XXIX Italian expedition. The concentration depth profile was obtained on the basis of the total concentration of fourteen PAHs and seven PCBs individually determined by gas chromatography triple quadrupole mass spectrometry. Both classes of pollutants showed synchronized concentration vs time profile throughout the whole period of time covered by the snow/firn core (1892–2012). A correlation between major explosive volcanic eruptions and the concentration maxima of the pollutants was found. PAH maximum (9 ng/L) was about twice the background level (5 ng/L). PCBs showed a similar but more limited trend with barely visible volcanic maxima. This concurrence highlights the contribution of the major explosive volcanic events to the global contamination level for PAHs, as expected, but also for PCBs whose industrial production and use began in 1930. Excluding the maximum values, PAHs and PCBs showed an increase in the period 1956–1986: PCBs from about 0.05 to 0.21 ng/l (400% increase), and PAHs from about 3.5 to 7.8 ng/l (100% increase). Finally, in the last decade (2000–2010) the trend of these pollutants was different: (i) PCBs constantly decrease (from 0.15 ng/L to 0.10 ng/L), thanks to the implemented restriction on their production and on their use only in closed systems in many countries; (ii) PAHs remains practically constant around 6.5 ng/L. [ABSTRACT FROM AUTHOR]

Iodine has proven to be a promising alternative to xenon as a propellant for Hall and ion thrusters. High atomic mass and favourable ionization characteristics, comparable to xenon in terms of propulsive performance, together with lower cost compared to xenon makes it an attractive option. However, its reactivity and corrosive nature raise concerns. Tests to assess material compatibility and determine whether thruster components are susceptible to corrosion are unavoidable for its safe adoption as a propellant. This paper describes the main results of an experimental campaign aimed at a qualitative assessment of the compatibility with iodine of different materials. The study included more than fifteen materials that find application in electric propulsion devices, such as cathodes, thrusters and feeding systems, including ceramics such as LaB 6 , polymers, iron and aluminum alloys, and graphite. The specimens were exposed to iodine vapor environments at temperatures reaching approximately 200 °C for extended periods (from three to over 30 h) or were directly exposed to liquid iodine. The experimental setup and results of morphological and elementary analyses are presented and discussed. The research provides some insights into the viability of using iodine as a propellant and the potential challenges associated with its corrosive properties. [ABSTRACT FROM AUTHOR]

The total mass of individual synthetic polymers present as microplastic (MP < 2 mm) pollutants in the sediments of interconnected aquatic environments was determined adopting the Polymer Identification and Specific Analysis (PISA) procedure. The investigated area includes a coastal lakebed (Massaciuccoli), a coastal seabed (Serchio River estuarine), and a sandy beach (Lecciona), all within a natural park area in Tuscany (Italy). Polyolefins, poly(styrene) (PS), poly(vinyl chloride) (PVC), polycarbonate (PC), poly(ethylene terephthalate) (PET), and the polyamides poly(caprolactame) (Nylon 6) and poly(hexamethylene adipamide) (Nylon 6,6) were fractionated and quantified through a sequence of selective solvent extractions followed by either analytical pyrolysis or reversed-phase HPLC analysis of the products of hydrolytic depolymerizations under acidic and alkaline conditions. The highest concentrations of polyolefins (highly degraded, up to 864 µg/kg of dry sediment) and PS (up to 1138 µg/kg) MPs were found in the beach dune sector, where larger plastic debris are not removed by the cyclic swash action and are thus prone to further aging and fragmentation. Surprisingly, low concentrations of less degraded polyolefins (around 30 µg/kg) were found throughout the transect zones of the beach. Positive correlation was found between polar polymers (PVC, PC) and phthalates, most likely absorbed from polluted environments. PET and nylons above their respective LOQ values were found in the lakebed and estuarine seabed hot spots. The pollution levels suggest a significant contribution from riverine and canalized surface waters collecting urban (treated) wastewaters and waters from Serchio River and the much larger Arno River aquifers, characterized by a high anthropogenic pressure. [ABSTRACT FROM AUTHOR]

Leather represents the principal industrial product derived from the skin of animals. Leather manufacturing has evolved from artisanal practice, making use of vegetable tannins, to industrial production, today mostly based on chromium salts. Chromium tanning accounts for the most efficient and affordable process available on the market, but the environmental pressure caused by heavy metal pollution has pushed towards the development of Metal-Free leather tanning agents. This paper aims at highlighting the potentialities and limits of analytical pyrolysis to characterise metal-free leather samples and to identify the tanning agents. To this aim, thirty-three bovine split leather samples tanned with various metal-free tanning agents (constituted by single or combined formulations of GRANOFIN® F90, glutaraldehyde, tetrakis(hydroxymethyl)phosphonium sulphate, oxazolidine and three different synthetic tannins), provided by bovine split suppliers (Tuscany, Italy) were analysed by flash Pyrolysis coupled with Gas Chromatography - Mass Spectrometry (Py-GC-MS). For most of the tanning formulations, Py-GC-MS was able to determine pyrolytic markers in reference materials, intermediates (wet-white metal-free and metal-free crust) and end-products (metal-free final products). Evolved Gas Analysis coupled with Mass Spectrometry (EGA-MS) was used to evaluate, from the molecular point of view, the thermodegradative profiles of metal-free leathers and compare them with that of chromium tanned leather. • Py-GC-MS was tested to characterise metal-free leather samples. • Pyrolytic markers were determined for most of tanning formulations investigated. • Py-GC-MS was proposed as aneasy-to-use method for the analysis of leathers products at each stage of the production. • The semi-quantitative evaluation of the pyrograms allowed to roughly indicate the proportions of the tanning agents. • EGA-MS was used to evaluate the different thermal stability of wet-white and wet-blue products. [ABSTRACT FROM AUTHOR]

Gold extraction from aqueous solutions has been performed by micellar enhanced ultrafiltration (MEUF), using SDS and DTAC micelles. DTAC entraps 92–100% of the metal, which is present in form of AuCl 4 − , owing to electrostatic interaction. Using SDS the extraction of gold is unsuccessful. However, addition of PADA, as a metal extractor agent, according to the ligand modified micellar enhanced ultrafiltration (LM-MEUF) procedure, makes the extraction yield to approach 100% also with SDS. The recovery of gold entrapped in the micellar pseudo-phase has also been investigated. Different stripping agents have been used, the most efficient of them being a mixture of NaCl and NH 3 which allowed the metal to be expelled from the micelle with a yield of 85%. Finally, Au(III)/Cu(II) separation is achieved with DTAC or SDS between pH 3 and 5. Almost 100% of Au(III) is retained on DTAC micelles while all Cu(II) remains in the aqueous medium, while the opposite occurs in SDS. [ABSTRACT FROM AUTHOR]

Pollution from microplastics (MPs) has become one of the most relevant topics in environmental chemistry. The risks related to MPs include their capability to adsorb toxic and harmful molecular species, and to release additives and degradation products into ecosystems. Their role as a primary source of a broad range of harmful volatile organic compounds (VOCs) has also been recently reported. In this work, we applied a non-destructive approach based on selected-ion flow tube mass spectrometry (SIFT-MS) for the characterization of VOCs released from a set of plastic debris collected from a sandy beach in northern Tuscany. The interpretation of the individual SIFT-MS spectra, aided by principal component data analysis, allowed us to relate the aged polymeric materials that make up the plastic debris (polyethylene, polypropylene, and polyethylene terephthalate) to their VOC emission profile, degradation level, and sampling site. The study proves the potential of SIFT-MS application in the field, as a major advance to obtain fast and reliable information on the VOCs emitted from microplastics. The possibility to obtain qualitative and quantitative data on plastic debris in less than 2 min also makes SIFT-MS a useful and innovative tool for future monitoring campaigns involving statistically significant sets of environmental samples. Image 1 • VOCs released from plastic debris were analyzed non-destructively by SIFT-MS. • Aged polymeric materials were characterized based on their SIFT-MS spectra. • PCA analysis of spectra correlated VOC profile, degradation level and sampling site. • SIFT-MS provided fast and reliable information on the VOCs emitted by microplastics. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) quantification in benthic marine sediments is typically performed by time-consuming and moderately accurate mechanical separation and microscopy detection. In this paper, we describe the results of our innovative Polymer Identification and Specific Analysis (PISA) of microplastic total mass, previously tested on either less complex sandy beach sediment or less demanding (because of the high MPs content) wastewater treatment plant sludges, applied to the analysis of benthic sediments from a sublittoral area north-west of Leghorn (Tuscany, Italy). Samples were collected from two shallow sites characterized by coarse debris in a mixed seabed of Posidonia oceanica, and by a very fine silty-organogenic sediment, respectively. After sieving at <2 mm the sediment was sequentially extracted with selective organic solvents and the two polymer classes polystyrene (PS) and polyolefins (PE and PP) were quantified by pyrolysis-gas chromatography-mass spectrometry (Pyr-GC/MS). A contamination in the 8–65 ppm range by PS could be accurately detected. Acid hydrolysis on the extracted residue to achieve total depolymerization of all natural and synthetic polyamides, tagging of all aminated species in the hydrolysate with a fluorophore, and reversed-phase high performance liquid chromatography (HPLC) (RP-HPLC) analysis, allowed the quantification within the 137–1523 ppm range of the individual mass of contaminating nylon 6 and nylon 6,6, based on the detected amounts of the respective monomeric amines 6-aminohexanoic acid (AHA) and hexamethylenediamine (HMDA). Finally, alkaline hydrolysis of the residue from acid hydrolysis followed by RP-HPLC analysis of the purified hydrolysate showed contamination by polyethylene terephthalate (PET) in the 12.1–2.7 ppm range, based on the content of its comonomer, terephthalic acid. [ABSTRACT FROM AUTHOR]