Search results for "ambiente"
showing 10 items of 1727 documents
Mutazioni del paesaggio ai tempi della diffusione dei centri commerciali
2014
Il contributo intende riflettere sulla scelta operata da parte di diverse amministrazioni locali che negli ultimi anni, dietro l’alibi di ampliare la gamma delle occasioni di sviluppo, hanno assecondato acriticamente, quantomeno in Sicilia, le iniziative imprenditoriali relative alla realizzazione di grandi centri commerciali e/o di intrattenimento. Spesso la loro realizzazione è stata prevista in aree contigue a quartieri periferici, con l’auspicio che la presenza di un grande attrattore commerciale potesse innescare processi di rigenerazione urbana. In realtà l’ubicazione di tali strutture, pensata in stretta simbiosi con la grande viabilità, risponde a precise logiche speculative molto d…
Polycyclic aromatic hydrocarbons (PAHs) in indoor emission from decorative candles
2011
Abstract This study investigates PAHs indoor emissions from burning decorative candle in an indoor environment because emissions from burning wax in home have rarely been addressed. A total of 12 air samples were collected during the entire burning period of the decorative candles. Particulate and gaseous PAHs emissions were simultaneously measured by passing effluent through a filter (to collect particulate-phase PAHs), a cold trap and ORBO 43 tubes (to capture gaseous-phase PAHs). Analysis involved ultrasound extraction, followed by gas chromatography–mass spectrometry (GC–MS). The measured total PAHs concentration (particulate + aqueous phase + gas phases) for the candles, reported as ma…
Cyclodextrin/surfactant inclusion complexes: An integrated view of their thermodynamic and structural properties
2021
Cyclodextrins (CDs) play an important role in self-assembly systems of amphiphiles. The structure of CDs provides distinguished physicochemical properties, including the ability to form host-guest complexes. The complexation affects the properties of guest molecules and can produce supramolecular aggregates with desirable characteristics for fundamental and practical applications. Surfactants are particularly attractive host molecules due to their wide variety, availability, responsiveness to different stimuli, and high relevance in different fields, e.g. medical, cosmetic, pharmaceutical, and food industries. The tendency of organization in higher-order supramolecular aggregates arises the…
Exploring the limits of anaerobic biodegradability of urban wastewater by AnMBR technology
2018
[EN] Anaerobic membrane bioreactors (AnMBRs) can achieve maximum energy recovery from urban wastewater (UWW) by converting influent COD into methane. The aim of this study was to assess the anaerobic biodegradability limits of urban wastewater with AnMBR technology by studying the possible degradation of the organic matter considered as non-biodegradable as observed in aerobic membrane bioreactors operated at very high sludge retention times. For this, the results obtained in an AnMBR pilot plant operated at very high SRT (140 days) treating sulfate-rich urban wastewater were compared with those previously obtained with the system operating at lower SRT (29 to 70 days). At 140 days SRT the …
Contamination from polycyclic aromatic hydrocarbons (PAHs) in the soil of a botanic garden localized next to a former manufacturing gas plant in Pale…
2010
The Botanical Garden lies within the city of Palermo, a few meters away from one of the largest unused Manufacturing Gas Plant in Sicily. The total concentrations of PAHs (23 compounds) in the soil of Botanical Garden ranged from 947 to 18,072 microg/kg. The wide range of PAH concentrations (RSD=84%) found in the soil samples indicates heterogeneous levels of contamination in the area and this can be explained by considering the different tree distributions which prevents the homogeneous deposition of pollutants on the soil. Soils collected in the Botanical Garden generally showed the highest PAH concentrations, being almost 2-3 times higher than the concentration samples obtained in the ur…
Chemical speciation of polycyclic aromatic hydrocarbons in sediments: partitioning and extraction of humic substances.
2010
The primary objective of this study was to examine the chemical speciation of polycyclic aromatic hydrocarbons (PAHs) found in sediments endowed with different characteristics. To achieve this purpose and because the nature of the sediments influences the distribution of PAHs, we have analyzed four different types of sediments. To study the role of organic matter in the sequestration of PAHs, we fractionated humic substances into humic acids and humin–mineral fractions. After their separation and purification, the humic components were examined for their sorptive reactivity by extracting them with organic solvents; these extracts were subsequently subjected to GC/MS analysis. Our results sh…
Polycyclic Aromatic Hydrocarbons in Sediments of Marine Coastal Lagoons in Messina, Italy: Extraction and GC/MS Analysis, Distribution and Sources
2004
The content of 21 polycyclic aromatic hydrocarbons (PAHs) has been determined in 16 samples of sediments collected from Ganzirri and Faro marine coastal lagoons in Messina (Italy). Analysis was performed by gas chromatography/mass spectrometry (GC/MS) in selected ion monitoring (SIM) mode. The total concentration of polycyclic aromatic hydrocarbons (PAHs) ranged from 74 to 5755 ...g/Kg of dry matrix. The resulting distributions and molecular ratios of specific compounds have been discussed in terms of sampling location and origin of organic matter. The results obtained show that levels of contamination are not homogeneous throughout the stations, while the relative distributions of PAH are…
Determination of selected polyaromatic hydrocarbons by gas chromatography–mass spectrometry for the analysis of wood to establish the cause of sinkin…
2014
Abstract The aim of this paper was to establish the cause of sinking of an old wooden vessel by polycyclic aromatic hydrocarbon (PAH) analyses because wood combustion is a source of PAHs. In particular, the molecular PAH patterns generated by each source are like fingerprints and it is possible to determine the processes that generate PAHs by studying their distribution in wood samples. The relative abundance of high molecular weight PAHs, together with the PAH compound ratios and with total index (proposed by us) has demonstrated that samples owe their PAHs in wood archaeological material to a predominant single mode of origin, i.e. combustion processes, therefore we can say that the sinki…
Platinum in indoor settled dust matter (homes and cars)
2015
Abstract This paper presents a method for Pt analysis in indoor (homes and cars) settled dust, used as passive samplers, and the results relative to samples collected in the Sicilian area are used to evaluate the magnitude and distribution of concentrations inside common environments and the possible origins of the considered contaminant. The concentrations of platinum in settled indoor dust were measured by differential pulsed voltammetry (DPV). Concentrations of Pt in homes are in the range from 30 to 1460 μg kg − 1 d.w. while, in the vehicles from 30 to 1750 μg kg − 1 d.w. Considering the geoaccumulation index (I geo ), 42% of the settled dust sampled in homes could be classified as extr…