The use of nano-particles to produce iridescent metallic effects on ancient ceramic objects.

Nano-sized materials have been often used in the past to realize objects with particular characteristics. One of the most outstanding examples is represented by luster pottery, showing shining surfaces with particular optical properties. Luster was one of the most sophisticated technique for the decoration of majolicas. It consists of a thin metallic film containing silver, copper and other substances, like iron oxide and cinnabar, applied in a reducing atmosphere on a previously glazed ceramic. In such a way, beautiful iridescent reflections of different colours (in particular gold and ruby-red) are obtained. This technique, at first developed in Iraq, was introduced in Italy from Spain. In Italy the potters of the two centres of Gubbio and Deruta, in central Italy, became so expert that nowadays modern artisans are not able to reproduce the wonderful effects obtained during Renaissance. A complete characterization by means of numerous techniques has been carried out on a great number of shards and precious work of arts conserved in many important museums. This allowed to draw some correlations between the preparation technique and the obtained nano-structure.

Near-infrared LEDS provide persistent and increasing protection against E. faecalis.

In a previous study, we have shown that non-coherent light-emitting diodes (LEDs) are able to significantly decrease Enterococcus faecalis viability, in vitro. In particular, the concurrent treatment for 5 min with sodium hypochlorite (NaOCl) 1.0% and LED permitted to obtain the total inactivation of the culture. The primary outcome of this study was to verify if the photoinactivation was only temporary or stable over 1 week. The secondary outcome was to verify if using a minor concentration of NaOCl together with LED irradiation, it was possible to reach the total inactivation of the culture. Bacterial suspensions were subjected to different protocols. NaOCl samples were treated with 0.5% sodium hypochlorite for 5 min; LED 5 were subjected to 880-nm LED irradiation for 5 min and LED+NaOCl were contemporary subjected to LED irradiation and 0.5% sodium hypochlorite for 5 min. Then the colony forming units per milliliter (CFU/mL) were analyzed and recorded at 5 min, 24 h, 48 h and 1 week. The data were submitted to ANOVA and LSD post hoc tests at a level of significance of 0.05. Live dead assay and fluorescent microscope observations were also performed for all group at all timing points. The results showed that the 3 protocol treatments were able to decrease significantly the bacterial count respect controls, however, after 5 min, 24 h and 48 h the most effective reduction was measured for NaOCl and NaOCl+LED 5. In the first 48 h LED 5 alone reduced significantly the bacterial count respect controls, but it was higher respect the other tested groups. On the contrary, after 1 week we found an interesting result: samples treated with LED were characterized by a decrement of bacterial count, independently from the addition of sodium hypochlorite. Samples treated with NaOCl alone were characterized by a mild increment of bacterial count, although results were still significant respect C+. The secondary outcome was not confirmed: a concentration of NaOCl 0.5% together with LED irradiation did not permit to reach the total inactivation of the culture.

Outdoor spatial distribution and indoor levels of NO2 and SO2 in a high environmental risk site of the South Italy.

In the frame of the project EDOC@WORK3.0, Education and Work on Cloud, a monitoring plan has been carried out in the highly industrialized town of Taranto (one of the most polluted sites of Italy) in order to investigate contemporary indoor and outdoor concentrations of NO2 and SO2 by passive sampling devises (Radiello). Simultaneously indoor and outdoor samplings of NO2 and SO2 were performed from 2nd November 2015 to 2nd December 2015 in nine sites scattered in the investigated area at different quotes and distances from the industrial complex. Our findings show substantial differences between the spatial distributions of the two pollutants and support the hypothesis of two different prevalent sources for NO2 and SO2. In particular, we find diffusive sources of NO2 linked mainly to the vehicular traffic and secondarily to industrial sources. In contrast, SO2 was mainly associated to industrial sources present in the area, representing also a proxy of the mixture of air contaminants associated to industrial processes. Our hypothesis is also confirmed by analysis of data measured by ARPA air quality monitoring stations. Comparison between indoor and outdoor concentrations confirms that outdoor pollutants infiltrate to indoor environments, moreover it highlights potential NO2 indoor sources basically linked to cooking activities, representing adverse health effects for population risk categories such as children or cooks. Considering that urban people spend a lot of their time in indoors, attention should be paid both to outdoor pollutant sources and to indoor sources.

Composition and origin of PM2.5 in Mediterranean Countryside.

In this work PM2.5 was collected during winter and summer in a Sardinian village (Gonnostramatza, Italy) highly affected by biomass burning emissions. A multi-technique approach was adopted for the complete PM chemical characterization. The bulk characterization was performed by IC (Ion Chromatography), HPAEC (High-Performance Anion-Exchange Chromatography), TOT (Thermal Optical Transmittance) and ED-XRF (Energy-Dispersive X-Ray Fluorescence) while XPS (X-ray Photoelectron Spectroscopy) was used for the surface characterization. Using levoglucosan as specific tracer of biomass burning emissions, the assessment of the impact of this source was carried out and it represent the major PM source at the investigate site during winter. In winter the average levoglucosan concentration is 2096 ±â€¯324 ng/m3 while during summer its concentration is negligible (18 ±â€¯7 ng/m3). Levoglucosan content in PM2.5 during winter is on average 13.7%; it is estimated that 65% of PM2.5 is due to wood burning. XPS has been exploited in this work aiming at highlighting possible differences between surface and bulk composition of PM2.5. The surface of the particulate matter resulted enriched in carbon compared to the bulk. Among the components of XPS C1s signals recorded on the samples collected during winter, it was found that the signal at 286.5 eV, which is due to the presence of COH, reflects the bulk composition of levoglucosan.

Assessment of light extinction at a European polluted urban area during wintertime: Impact of PM1 composition and sources.

In this paper, results from receptor modelling performed on a well-characterised PM1 dataset were combined to chemical light extinction data (bext) with the aim of assessing the impact of different PM1 components and sources on light extinction and visibility at a European polluted urban area. It is noteworthy that, at the state of the art, there are still very few papers estimating the impact of different emission sources on light extinction as we present here, although being among the major environmental challenges at many polluted areas. Following the concept of the well-known IMPROVE algorithm, here a tailored site-specific approach (recently developed by our group) was applied to assess chemical light extinction due to PM1 components and major sources. PM1 samples collected separately during daytime and nighttime at the urban area of Milan (Italy) were chemically characterised for elements, major ions, elemental and organic carbon, and levoglucosan. Chemical light extinction was estimated and results showed that at the investigated urban site it is heavily impacted by ammonium nitrate and organic matter. Receptor modelling (i.e. Positive Matrix Factorization, EPA-PMF 5.0) was effective to obtain source apportionment; the most reliable solution was found with 7 factors which were tentatively assigned to nitrates, sulphates, wood burning, traffic, industry, fine dust, and a Pb-rich source. The apportionment of aerosol light extinction (bext,aer) according to resolved sources showed that considering all samples together nitrate contributed at most (on average 41.6%), followed by sulphate, traffic, and wood burning accounting for 18.3%, 17.8% and 12.4%, respectively.

Archaeometric researches on the provenance of Mediterranean Archaic Phoenician and Punic pottery.

The aim of this study is to setup a first chemical database that could represent the starting point for a reliable classification method to discriminate between Archaic Phoenician and Punic pottery on the base of their chemical data. This database up to now can discriminate between several different areas of production and provenance and can be applied also to unknown ceramic samples of comparable age and production areas. More than 100 ceramic fragments were involved in this research, coming from various archaeological sites having a crucial importance in the context of the Phoenician and Punic settlement in central and western Mediterranean: Carthage (Tunisia), Toscanos (South Andalusia, Spain), Sulci, Monte Sirai, Othoca, Tharros (Sardinia, Italy) and Pithecusa (Campania, Italy). Since long-time archaeologists hypothesised that Mediterranean Archaic Phoenician and Punic pottery had mainly a local or just a regional diffusion, with the exception of some particular class like transport amphorae. To verify the pottery provenance, statistical analyses were carried out to define the existence of different ceramic compositional groups characterised by a local origin or imported from other sites. The existing literature data are now supplemented by new archaeometric investigations both on Archaic Phoenician ceramics and clayey raw materials from Sardinia. Therefore, diffractometric analyses, optical microscopy observations and X-ray fluorescence analyses were performed to identify the mineralogical and chemical composition of Othoca ceramics and clayey raw material. The obtained results were then compared with own literature data concerning Phoenician and Punic pottery in order to find features related to the different ceramic productions and their provenance. Principal component analysis (PCA) and hierarchical cluster analysis (HCA) were also performed on the chemical compositional data in order to discriminate ceramic groups. A very complex situation was found: imported ceramics coming from Carthage, with a large-scale distribution, were found together with a predominant local production pottery. The archaeometric results demonstrate that historical and typological approach has to be supported by scientific analyses to better understand local or Mediterranean exchanges.

Size-segregated aerosol in a hot-spot pollution urban area: Chemical composition and three-way source apportionment.

In this work, a comprehensive characterisation and source apportionment of size-segregated aerosol collected using a multistage cascade impactor was performed. The samples were collected during wintertime in Milan (Italy), which is located in the Po Valley, one of the main pollution hot-spot areas in Europe. For every sampling, size-segregated mass concentration, elemental and ionic composition, and levoglucosan concentration were determined. Size-segregated data were inverted using the program MICRON to identify and quantify modal contributions of all the measured components. The detailed chemical characterisation allowed the application of a three-way (3-D) receptor model (implemented using Multilinear Engine) for size-segregated source apportionment and chemical profiles identification. It is noteworthy that - as far as we know - this is the first time that three-way source apportionment is attempted using data of aerosol collected by traditional cascade impactors. Seven factors were identified: wood burning, industry, resuspended dust, regional aerosol, construction works, traffic 1, and traffic 2. Further insights into size-segregated factor profiles suggested that the traffic 1 factor can be associated to diesel vehicles and traffic 2 to gasoline vehicles. The regional aerosol factor resulted to be the main contributor (nearly 50%) to the droplet mode (accumulation sub-mode with modal diameter in the range 0.5-1 µm), whereas the overall contribution from the two factors related to traffic was the most important one in the other size modes (34-41%). The results showed that applying a 3-D receptor model to size-segregated samples allows identifying factors of local and regional origin while receptor modelling on integrated PM fractions usually singles out factors characterised by primary (e.g. industry, traffic, soil dust) and secondary (e.g. ammonium sulphate and nitrate) origin. Furthermore, the results suggested that the information on size-segregated chemical composition in different size classes was exploited by the model to relate primary emissions to rapidly-formed secondary compounds.

Advanced mortar coatings for cultural heritage protection. Durability towards prolonged UV and outdoor exposure.

In the present work, two kinds of hybrid polymeric-inorganic coatings containing TiO2 or SiO2 particles and prepared starting from two commercial resins (Alpha®SI30 and Bluesil®BP9710) were developed and applied to two kinds of mortars (an air-hardening calcic lime mortar [ALM] and a natural hydraulic lime mortar [HLM]) to achieve better performances in terms of water repellence and consequently damage resistance. The two pure commercial resins were also applied for comparison purposes. Properties of the coated materials and their performance were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Tests were also performed to determine the weathering effects on both the commercial and the hybrid coatings in order to study their durability. Thus, exposures to UV radiation, to UV radiation/condensed water cycles and to a real polluted atmospheric environment have been performed. The effectiveness of the hybrid SiO2 based coating was demonstrated, especially in the case of the HLM mortar.

On the role of hydrophobic Si-based protective coatings in limiting mortar deterioration.

In order to avoid both natural and artificial stone decay, mainly due to the interaction with atmospheric pollutants (both gases such as NOx and SO2 and particulate matter), polymeric materials have been widely studied as protective coatings enable to limit the penetration of fluids into the bulk material. In the current work, an air hardening calcic lime mortar (ALM) and a natural hydraulic lime mortar (HLM) were used as substrates, and commercially available Si-based resins (Alpha®SI30 and Silres®BS16) were adopted as protective agents to give hydrophobicity features to the artificial stones. Surface properties of coatings and their performance as hydrophobic agents were studied using different techniques such as contact angle measurements, capillary absorption test, mercury intrusion porosimetry, surface free energy, colorimetric measurements and water vapour permeability tests. Finally, some exposure tests to UV radiation and to real polluted atmospheric environments (a city centre and an urban background site) were carried out during a wintertime period (when the concentrations of the main atmospheric pollutants are higher) in order to study the durability of the coating systems applied. The effectiveness of the two commercial resins in reducing salt formation (sulphate and nitrate), induced by the interaction of the mortars with the atmospheric pollutants, was demonstrated in the case of the HLM mortar. Graphical Abstract ᅟ.

MSWI fly ash particle analysis by scanning electron microscopy-energy dispersive X-ray spectroscopy.

Municipal solid waste incinerator (MSWI) fly ash was investigated to study metal distribution on the particle surface. A detailed investigation into the distribution of chlorine, copper, iron, and zinc was carried out by electron microscopy coupled with X-ray fluorescence spectroscopy. Compositional and leaching test data were used to identify the correlation of significant variables and to formulate a hypothesis about metals speciation. The presence of copper chloride, iron, and zinc oxides was inferred. The iron and zinc accumulation in the submicron nuclei indicates that these metals came from the condensation of volatile species. As far as concerns copper, morphological data together with the element correlation study suggest that this element accumulates on particles involved in heterogeneous condensation processes. Furthermore, during such processes, particles of small size containing copper are formed.

Analytical characterization of municipal solid waste incinerator fly ash. Part II.

The synergy of the micro FT-IR (Fourier Transform-Infrared) and SEM-EDX (Scanning Electron Microscopy-Energy Dispersive X-ray) techniques has been shown to be particularly helpful and effective for the characterization of inorganic compounds in fly ashes. The experimental data obtained by these techniques have been interpreted in comparison with those of other techniques. The presence of calcium carbonate, some sulfates, ammonium nitrate, calcium hydrogen phosphate, some chlorides, some oxides and aluminium silicates have been verified.

Thermal oxidation kinetics and mechanism of sludge from a wastewater treatment plant.

The organic fraction of a sludge from a wastewater biological treatment plant is characterized by the total organic carbon, TOC, content, cyclohexane and toluene extractions, and thermal desorptions in nitrogen and air flow at different temperatures. The inorganic fraction is characterized by water extraction, FT-IR spectroscopy, thermogravimetric analysis, and scanning electron microscopy/energy dispersion X-ray analysis. The thermal degradation rate of organic carbon is studied in batch experiments in air, in the 250-500 degrees C temperature range. The sample TOC is used to measure the decrease of reagent concentration with time. The TOC vs time data are well fitted by a generalized kinetic model, previously proposed for the MSWIs fly ash thermal degradation. The rate constants of the immediate carbon gasification, k2, and of the dissociative oxygen chemisorption, k1, followed by C(O) intermediate gasification, k3, together with activation and thermodynamic parameters are calculated. The rate determining step is the C(O) oxidation. The influence of desorbed or extracted organic compounds on kinetics and the role of the C(O) formation in explaining the reaction mechanism as well as the comparison with fly ash kinetics are discussed.