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Large-pore silica spheres as support for samarium-coordinated undecamolybdophos...
Mirante, Fátima; Alves, Ana C.; Julião, Diana; Almeida, Pedro L.; Gago, S.; Valença, Rita; Ribeiro, Jorge; De Castro, Baltazar; Granadeiro, CarlosA novel composite has been prepared through the immobilization of the Keggin sandwich-type [Sm (PMo11O39)(2)](11-) anion (SmPOM) on large-pore silica spheres previously functionalized with trimethylammonium groups (TMA). The resulting SmPOM@TMA-LPMS material has been evaluated as heterogeneous catalyst in a biphasic desulfurization 1:1 diesel/extraction solvent system using H2O2 as oxidant. Preliminary experime...
Mesoporous nanosilica-supported polyoxomolybdate as catalysts for sustainable d...
Mirante, Fátima; Gomes, Neide; Branco, Luis; Cunha-Silva, Luís; Almeida, Pedro L.; Pillinger, Martyn; Gago, S.; Granadeiro, Carlos; Balula, SaleteMesoporous silica nanoparticles (MSNs) strategically functionalized were used to immobilize a homogeneous polyoxomolybdate catalyst [PMo12O40](3-) (PMo12), active but unstable. The PMo12@TBA-MSN composite (where TBA refers to surface-tethered tributylammonium groups) conferred high stability to the polyoxomolybdate catalytic center and displayed an increase in efficiency for the oxidative desulfurization (ECODS...
Mesoporous nanosilica-supported polyoxomolybdate as catalysts for sustainable d...
Mirante, Fátima; Gomes, Neide; Branco, Luís C.; Cunha-Silva, Luís; Almeida, Pedro L.; Pillinger, Martyn; Gago, Sandra; Granadeiro, Carlos M.Mesoporous silica nanoparticles (MSNs) strategically functionalized were used to immobilize a homogeneous polyoxomolybdate catalyst [PMo12O40]3- (PMo12), active but unstable. The PMo12@TBA-MSN composite (where TBA refers to surface-tethered tributylammonium groups) conferred high stability to the polyoxomolybdate catalytic center and displayed an increase in efficiency for the oxidative desulfurization (ECODS) ...
Efficient heterogeneous polyoxometalate-hybrid catalysts for the oxidative desu...
Mirante, Fátima; Dias, Luís; Silva, Mariana; Ribeiro, Susana; Corvo, Marta C.; De Castro, Baltazar; Granadeiro, Carlos; Balula, SaleteThe heterogenization of the highly active monovacant polyoxotungstate ([PW11O39](7-), abbreviated as PW11) was achieved by preparing the corresponding long chain quaternary ammonium salt (ODA(7)PW(11), ODA = CH3(CH2)(17)(CH3)(3)N). The complete cation exchange confers total heterogeneity to the monovacant catalyst while keeping its oxidative catalytic activity. In fact, the heterogeneous catalyst allowed for th...
Road tunnel, roadside, and urban background measurements of aliphatic compounds...
Oliveira, Cesar; Martins, Natercia; Mirante, Fátima; Caseiro, Alexandre; Pio, Casimiro; Matos, Manuel; Silva, Hugo; Oliveira, Cristina; Camões, FilomenaParticulate matter samples were collected in a road tunnel in Lisbon (PM0.5, PM0.5-1, PM1-2.5, and PM2.5-10) and at two urban locations representing roadside and background stations (PM2.5 and PM2.5-10). Samples were analysed for organic and elemental carbon (OC and EC), n-alkanes, n-alkenes, hopanes, some isoprenoid compounds, and steranes. Particulate matter concentrations in the tunnel were 17-31 times highe...
Size fractionated aerosol composition at roadside and background environments i...
Mirante, Fátima; Salvador, Pedro; Pio, Casimiro; Alves, Célia; Artiñano, Begoña; Caseiro, Alexandre; Revuelta, M. AranzazuThe chemical composition of size-segregated particulate matter (PM) was studied during summer and winter sampling campaigns, at two different urban sites (roadside and urban background) in the city of Madrid, Spain. PM was sampled with high volume cascade impactors, in 4 size ranges: 10-2.5, 2.5-1, 1-0.5 and <0.5??m. The carbonaceous content (OC and EC) was determined by a thermo-optical method, whilst the wate...
Size-segregated chemical composition of aerosol emissions in an urban road tunn...
Pio, Casimiro; Mirante, Fátima; Oliveira, Cesar; Matos, Manuel; Caseiro, Alexandre; Oliveira, Cristina; Querol, Xavier; Alves, Célia; Martins, NatérciaAn atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5-1, PM1-2.5 and PM2.5-10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble inorganic ions and elemental composition. Three main groups of com...
Size-segregated chemical composition of aerosol emissions in an urban road tunn...
Pio, Casimiro; Mirante, Fátima; Oliveira, César João Santos; Matos, Manuel; Caseiro, Alexandre; Oliveira, Cristina; Querol, Xavier; Alves, CéliaAn atmospheric aerosol study was performed in 2008 inside an urban road tunnel, in Lisbon, Portugal. Using a high volume impactor, the aerosol was collected into four size fractions (PM0.5, PM0.5–1, PM1–2.5 and PM2.5–10) and analysed for particle mass (PM), organic and elemental carbon (OC and EC), polycyclic aromatic hydrocarbons (PAH), soluble inorganic ions and elemental composition. Three main groups of com...
Organic composition of size segregated atmospheric particulate matter, during s...
Mirante, Fátima; Alves, Célia; Pio, Casimiro; Pindado, Oscar; Perez, Rosa; Revuelta, Ma Aranzazu; Artiñano, BegoñaMadrid, the largest city of Spain, has some and unique air pollution problems, such as emissions from residential coal burning, a huge vehicle fleet and frequent African dust outbreaks, along with the lack of industrial emissions. The chemical composition of particulate matter (PM) was studied during summer and winter sampling campaigns, conducted in order to obtain size-segregated information at two different ...
Organic speciation of aerosols from wildfires in central Portugal during summer...
Vicente, Ana; Alves, Célia; Monteiro, Cristina; Nunes, Teresa; Mirante, Fátima; Cerqueira, Mário; Calvo, Ana; Pio, CasimiroThe aim of this study was the detailed organic speciation of fine (PM2.5) and coarse (PM2.5–10) particles and gaseous carbonyl compounds from plumes emitted by wildfires during the summer of 2009 in Portugal. Complementary characterisation of the smoke particulate inorganic fraction, along with emission factors of major trace gases, have already been published in Atmospheric Environment. The detailed speciation...