Elisa Venturini

Bulk deposition close to a Municipal Solid Waste incinerator: One source among many

In order to assess the contribution of a Municipal Solid Waste incinerator to the areas total contamination, metals and soluble ions have been determined in bulk deposition collected at sites affected by different levels of plant emissions, according to the results of the Calpuff air dispersion model. Results show that in general fluxes monitored at the different sites during the same period are quite similar for each analyte. Deposition fluxes of nitrite and ammonium are significantly lower at the more distant site, while copper is significantly higher at this site, possibly because of copper fungicide used on the nearby agriculture land. The presence of sea spray and resuspended soil dust can be inferred from Pearson correlation coefficients, while enrichment factors indicate that Cu, Pb and Zn have a probable anthropogenic origin. A more complete evaluation of the sources affecting the area was obtained with PMF analysis. The sources associated with each factor were identified from the source profile and temporal trends. Six factors were identified, three sources associate with natural matrices, while three factors represent anthropogenic sources. The greatest contribution of heavy metals, the most toxic and persistent components determined, is associated with resuspended soil dust, especially when weighted according to their toxicity. The anthropogenic source contribution is similar at all sites, and therefore the incinerators relative contribution to the total pollutant load appears to be negligible compared to other sources affecting the area.

Source apportionment and location by selective wind sampling and Positive Matrix Factorization

In order to determine the pollution sources in a suburban area and identify the main direction of their origin, PM2.5 was collected with samplers coupled with a wind select sensor and then subjected to Positive Matrix Factorization (PMF) analysis. In each sample, soluble ions, organic carbon, elemental carbon, levoglucosan, metals, and Polycyclic Aromatic Hydrocarbons (PAHs) were determined. PMF results identified six main sources affecting the area: natural gas home appliances, motor vehicles, regional transport, biomass combustion, manufacturing activities, and secondary aerosol. The connection of factor temporal trends with other parameters (i.e., temperature, PM2.5 concentration, and photochemical processes) confirms factor attributions. PMF analysis indicated that the main source of PM2.5 in the area is secondary aerosol. This should be mainly due to regional contributions, owing to both the secondary nature of the source itself and the higher concentration registered in inland air masses. The motor vehicle emission source contribution is also important. This source likely has a prevalent local origin. The most toxic determined components, i.e., PAHs, Cd, Pb, and Ni, are mainly due to vehicular traffic. Even if this is not the main source in the study area, it is the one of greatest concern. The application of PMF analysis to PM2.5 collected with this new sampling technique made it possible to obtain more detailed results on the sources affecting the area compared to a classical PMF analysis.

A New Porous Hybrid Material Derived From Silica Fume and Alginate for Sustainable Pollutants Reduction

In this work a new mesoporous adsorbent material obtained from a natural, high abundant raw material and a high volume industrial by-product is presented. The material is consolidated by the gelling properties of alginate and by decomposition of sodium-bicarbonate controlled porosity at low temperatures (70–80°C) at different scale lengths. The structural, thermal, and morphological characterization shows that the material is a mesoporous organic-inorganic hybrid. The material is tested as adsorbent, showing high performances. Methylene blue, used as model pollutant, can be adsorbed and removed from aqueous solutions even at a high concentration with efficiency up to 94%. By coating the material with a 100 nm thin film of titania, good photodegradation performance (more than 20%) can be imparted. Based on embodied energy and carbon footprint of its primary production, the sustainability of the new obtained material is evaluated and quantified in respect to activated carbon as well. It is shown that the new proposed material has an embodied energy lower than one order of magnitude in respect to the one of activated carbon, which represents the gold standards. The versatility of the new material is also demonstrated in terms of its design and manufacturing possibilities In addition, this material can be printed in 3D. Finally, preliminary results about its ability to capture diesel exhaust particulate matter are reported. The sample exposed to diesel contains a large amount of carbon in its surface. At the best of our knowledge, this is the first time that hybrid porous materials are proposed as a new class of sustainable materials, produced to reduce pollutants in the wastewaters and in the atmosphere.

Heteroaromatic Chromophores: Structure, Electric Properties, Condensed Phase and Aggregation Effects: a Combined Experimental and Theoretical Study

We present a combined computational and experimental study on structural and electric properties of recently synthesized heteroaromatic dyes and their simple aggregates. Ab initio and density functional theory calculations are carried out to investigate ground state and excited state properties along with their modulation induced by the solvent described with the implicit solvent polarizable continuum model. The results are compared with experimental data concerning spectroscopic studies. Electronic and vibrational contributions to the first hyperpolarizability and condensed phase effects on these properties are also evaluated for single or selected dimeric chromophore structures. Intermolecular interactions are evaluated both at correlated ab initio level and with simplified atomistic models employing molecular mechanics force fields parametrized, as regard electrostatic interactions, on the basis of ab initio computed partial atomic charges. Specific chromophore orientations are considered and the resul...