Search results for "Fondamenti"
showing 10 items of 542 documents
POLYMER ELECTROSPUN NANOFIBERS AS INTERLEAVES FOR ENANCHEMENT OF CFRP LAMINATES DELAMINATION RESISTANCE
2019
Electrospinning process is a technique to produce nanoscale fibers that has evinced more interest in recent years due to its versatility and potential for applications in several applications. The mall size and the concomitant ultra-high specific surface area of electrospun nanofibers make them suitable for several applications, such as tissue engineering, biosensors, filtration and advanced polymer composites (1). In particular for carbon fiber reinforced polymers (CFRPs) the huge specific surface area of electrospun nanofibers results in very large interfacial area between nanofibers and polymer matrix and therefore leads to substantial improvement of fiber-matrix interfacial interactions…
TIO2 brookite: Properties, synthesis and applications
2017
Brookite is one of the less studied polymorphic phases of titanium dioxide. Indeed, synthetic procedures affording brookite as a pure phase were not straightforward and have been only recently optimized. For this reason, brookite has received particular attention in the last years, especially as a promising photocatalytic material for environmental remediation and for the synthesis of valuable organic products. The present chapter will review the main synthetic methods reported in literature to produce brookite as a pure phase or mixed with rutile and/or anatase. Morphological, structural and electronic properties both of pure or variously modified brookite will be presented. The particular…
REWAQUA: an advanced technology for water purification in sustainable aquaculture based on photocatalytic ozonation
2017
The present study has been undertaken in order to test the real potential of photocatalytic ozonation in a bench-scale recirculating aquaculture system working on a 180 L reef coral aquarium. Notably, this choice may be considered representative. In fact, (i) the system is virtually closed so that fresh water turnover is practically negligible, (ii) the presence of living organisms is highly diversified (corals, fishes, molluscs, echinoderms and crustaceans) and some of them are particularly sensitive to water quality, (iii) high salinity strongly puts a strain on the purification system. The hereby presented purification method has been named REWAQUA, which stands for REcycling Water for A…
Biological effects and photodegradation by TiO(2) of terpenes present in industrial wastewater.
2010
Abstract The aim of this work was to study the biological effects of four monoterpenes, i.e. α-pinene, β-pinene, 3-carene and d -limonene present in the wastewater of a citrus transformation factory. The study was carried out by exposing V79 Chinese hamster cells to single terpene or to the mixture of four terpenes at concentrations corresponding to those in the wastewater evaluated by head space solid phase micro extraction and gas chromatography (HS-SPME-GC) analyses. Treatments with single or combined terpenes similarly affected cell vitality, but only the combined treatments induced the 6-thioguanine resistant mutants. Moreover the photocatalytic degradation of the four terpenes was suc…
A survey of photocatalytic materials for environmental remediation
2012
Abstract Heterogeneous photocatalysis is an advanced oxidation process which has been the subject of a huge amount of studies related to air cleaning and water purification. All these processes have been carried out mainly by using TiO 2 -based materials as the photocatalysts and ca. 75% of the articles published in the last 3 years is related to them. This review illustrates the efforts in the search of alternative photocatalysts that are not based on TiO 2 , with some exceptions concerning particularly innovative modifications as nanoassembled TiO 2 or TiO 2 composites with active carbon, graphite and fullerene. Papers reporting preparation, characterization and testing of binary, ternary…
Sequential biological and photocatalysis based treatments for shipboard slop purification: A pilot plant investigation
2019
This study investigated the treatment of a shipboard slop containing commercial gasoline in a pilot plant scale consisting of a membrane biological reactor (MBR) and photocatalytic reactor (PCR) acting in series. The MBR contributed for approximately 70% to the overall slop purification. More precisely, the biological process was able to remove approximately 40%, on average, of the organic pollution in the slop. Nevertheless, the membrane was capable to retain a large amount of organic molecules within the system, amounting for a further 30% of the influent total organic content removal. However, this affected the membrane fouling, thus resulting in the increase of the pore blocking mechani…
Photocatalytic activity of TiO2/SiO2 systems
2009
Silica-supported TiO(2) powders were synthesized by a wet method under mild conditions. The aim of the work was the preparation of TiO(2)/SiO(2) additives for photocatalytic cements. Three types of commercial SiO(2) were used as supports: Cabot, Axim and Fly Ash. Cabot silica was ultra-pure whereas the other two silica contained different percentages of various oxides. The TiO(2)/SiO(2) samples, denoted TiO(2)/Cabot, TiO(2)/Axim and TiO(2)/Fly Ash, were prepared by boiling suspensions obtained by addition of silica to a solution of TiCl(4) in water (volume ratio 1:10). The photocatalytic activity was evaluated in a gas-solid system both in batch and in continuous reactors using 2-propanol a…
Photochemical and photocatalytic isomerization of trans -caffeic acid and cyclization of cis -caffeic acid to esculetin
2016
Abstract The photoisomerization of trans-caffeic acid to cis-caffeic acid has been studied in the presence of N2 in homogeneous aqueous solutions and in suspensions of various TiO2 catalysts. The results supported the hypothesis of an energy transfer process from TiO2 to the substrate due to the recombination of the photogenerated electron–hole pairs. The differences among the measured photostationary [cis]/[trans] ratios have been attributed to the different physico-chemical properties of the catalysts. In particular, the lowest ratio measured in the presence of Merck TiO2 was ascribed to the very low adsorption of trans-caffeic acid onto the surface of this sample. In the presence of O2 a…
Attività catalitica e fotocatalitica di eteropoliacidi Wells-Dawson e Keggin per la disidratazione del 2-propanolo in regime gas-solido
2016
Tra i più studiati poliossometallati (nanoagglomerati di ossigeno con metalli transizionali), figurano gli eteropoliacidi (EPA) che sono degli acidi inorganici forti con ben defin ite strutture molecolari. In funzione della loro geometria, essi vengono classificati come Keggin e Wells-Dawson. Gli (EPA) sono usati in catalisi omogenea ed eterogenea e funzionano anche come fotocatalizzatori, essenzialmente in sistemi omogenei. Questi materiali sono, inoltre, economici e non tossici.
Opals infiltrated with a stimuli-responsive hydrogel for ethanol vapor sensing
2013
We report on a novel class of optical materials for ethanol vapor sensing, based on polystyrene opals infiltrated with an innovative stimuli responsive hydrogel. We describe the fabrication process of the bare polystyrene opals and their subsequent infiltration. The optical characterization of the photonic crystal templates was performed to prove the good quality of the samples. Measurements on the infiltrated opals showed that the transmission spectra in the visible range strongly change at varying concentrations of ethanol vapor. The fabricated structures show a linear optical response in the visible range, for high values of ethanol concentration.