Contributi per una flora vascolare di Toscana. XI (664-738)

Vengono presentate nuove località e/o conferme relative 75 taxa specifici e sottospecifici di piante vascolari della flora vascolare toscana, appartenenti a 67 generi e 41 famiglie: Delosperma (Aizoaceae), Dysphania (Amaranthaceae), Leucojum, Nothoscordum (Amaryllidaceae), Bupleurum, Coriandrum (Apiaceae), Araujia (Apocynaceae), Lemna (Araceae), Hydrocotyle (Araliaceae), Aristolochia (Aristolochiaceae), Bellevalia (Asparagaceae), Asphodelus (Asphodelaceae), Artemisia, Crepis, Eclipta, Erigeron, Hieracium, Senecio, Symphyotrichum, Tolpis (Asteraceae), Symphytum (Boraginaceae), Alyssum, Cardamine, Eruca, Isatis (Brassicaceae), Valerianella (Caprifoliaceae), Petrorhagia, Scleranthus (Caryophyllaceae), Commelina (Commelinaceae), Dichondra (Convolvulaceae), Sedum (Crassulaceae), Diospyros (Ebenaceae), Moneses (Ericaceae), Euphorbia (Euphorbiaceae), Medicago, Trifolium (Fabaceae), Myriophyllum (Haloragaceae), Juncus (Juncaceae), Salvia, Teucrium (Lamiaceae), Broussonetia (Moraceae), Spiranthes (Orchidaceae), Phelipanche (Orobanchaceae), Papaver (Papaveraceae), Passiflora (Passifloraceae), Cedrus, Pseudotsuga (Pinaceae), Bromopsis, Calamagrostis, Cenchrus, Drymochloa, Melica, Oloptum, Phleum, Sporobolus, Tragus (Poaceae), Stuckenia (Potamogetonaceae), Lysimachia (Primulaceae), Anemone, Aquilegia (Ranunculaceae), Eriobotrya (Rosaceae), Crucianella (Rubiaceae), Verbascum (Scrophulariaceae), Typha (Typhaceae), Urtica (Urticaceae), Viola (Violaceae). Infine, viene discusso lo status di conservazione delle entità e gli eventuali vincoli di protezione dei biotopi segnalati.New localities and/or confirmations concerning 75 specific and subspecific plant taxa of Tuscan vascular flora, belonging to 67 genera and 41 families are presented: Delosperma (Aizoaceae), Dysphania (Amaranthaceae), Leucojum, Nothoscordum (Amaryllidaceae), Bupleurum, Coriandrum (Apiaceae), Araujia (Apocynaceae), Lemna (Araceae), Hydrocotyle (Araliaceae), Aristolochia (Aristolochiaceae), Bellevalia (Asparagaceae), Asphodelus (Asphodelaceae), Artemisia, Crepis, Eclipta, Erigeron, Hieracium, Senecio, Symphyotrichum, Tolpis (Asteraceae), Symphytum (Boraginaceae), Alyssum, Cardamine, Eruca, Isatis (Brassicaceae), Valerianella (Caprifoliaceae), Petrorhagia, Scleranthus (Caryophyllaceae), Commelina (Commelinaceae), Dichondra (Convolvulaceae), Sedum (Crassulaceae), Diospyros (Ebenaceae), Moneses (Ericaceae), Euphorbia (Euphorbiaceae), Medicago, Trifolium (Fabaceae), Myriophyllum (Haloragaceae), Juncus (Juncaceae), Salvia, Teucrium (Lamiaceae), Broussonetia (Moraceae), Spiranthes (Orchidaceae), Phelipanche (Orobanchaceae), Papaver (Papaveraceae), Passiflora (Passifloraceae), Cedrus, Pseudotsuga (Pinaceae), Bromopsis, Calamagrostis, Cenchrus, Drymochloa, Melica, Oloptum, Phleum, Sporobolus, Tragus (Poaceae), Stuckenia (Potamogetonaceae), Lysimachia (Primulaceae), Anemone, Aquilegia (Ranunculaceae), Eriobotrya (Rosaceae), Crucianella (Rubiaceae), Verbascum (Scrophulariaceae), Typha (Typhaceae), Urtica (Urticaceae), and Viola (Violaceae). In the end, the conservation status of the units and eventual protection of the cited biotopes are discussed

DEVELOPMENT AND APPLICATION OF THE ZERO LENGTH COLUMN (ZLC) TECHNIQUE FOR MEASURING ADSORPTION EQUILIBRIA BY

This thesis reports the results of an experimental study aimed at developing the "zero length column " (ZLC) method as a useful technique for measuring adsorption equilibria. In a ZLC experiment a small sample of adsorbent is preequilibrated with the sorbate, at a known partial pressure, in a He carrier. Information concerning the sorption kinetics and equilibria can be obtained fkom the desorption curve when the flow is switched to a pure He purge under carefully controlled conditions. This technique has been widely used to measure intraparticle diffusivities but, when operated at sufficiently low flow rate, it provides a simple and convenient way to obtain equilibrium data, including both Henry's Law constants and complete isotherms. The practical viability and limitations of this approach have been explored by measuring the adsorption isotherms for COz on several different zeolites on the sameadsorbents and under the same conditions at which the isotherms had been measured, at the Air Products Laboratory, by a conventional volumetric/piezometric method. It was shown that; with careful attention to the details of the experiment, the ZLC measurement replicates the volumetric/piezometric isotherms within a few percent

Biomethane production by adsorption technology: New cycle development, adsorbent selection and process optimization

International audienceGas separation by adsorption processes such as pressure swing adsorption (PSA) presents an attractive alternative for upgrading biogas to biomethane. A new vacuum pressure swing adsorption (VPSA) cycle is proposed for a unit designed to purify pre-cleaned biogas (40% CO 2 and 60% CH 4) in industrial conditions (feed flow rate more than 500Nm 3 /h and large-volume equipment). The process simulations performed to optimize the VPSA unit consider the kinetic separation of the feed components by using an appropriate carbon molecular sieve (CMS) adsorbent having a high kinetic separation selectivity for CO 2 with respect to CH 4. The designed VPSA unit is composed of five columns that perform three equalization steps. Minimizing methane losses during the regeneration steps necessitates injecting part of the off-gas rich in CO 2 at the bottom of the column during the production step to push the CH 4 forward. The produced biomethane meets the specification (97% CH 4) of grid injection purity. The developed cycle allows a CH 4 recovery of 92% to be obtained with a specific energy consumption of 0.35kWh/Nm 3 , thus meeting the initial requirements for industrial exploitation of VPSA technology for biomethane purification from biogas sources

MW-Assisted Regeneration of 13X Zeolites after N₂O Adsorption from Concentrated Streams: A Process Intensification

N2O has a global warming potential about 300 times higher than CO2, and even if its contribution to the greenhouse effect is underrated, its abatement in industrial production’s tail gas has become imperative. In this work, we investigate the feasibility of the microwave (MW)-assisted regeneration of a 13X zeolite bed for N2O capture from tail gases. Several consecutive adsorption–desorption cycles were performed to verify the microwave heating effect on the zeolite’s adsorption properties. The results of the experimental tests, performed at N2O concentrations of 10, 20 and 40% vol, highlighted that (i) the steps are perfectly repeatable in terms of both adsorbed and desorbed amount of N2O, meaning that the MWs did not damage the zeolite’s structure, (ii) the presence of both H2O and O2 in the feed stream irreversibly reduces the adsorbent capacity due to nitrites and nitrates formation, and (iii) the presence of H2O alone with N2O still reduces the adsorbent capacity of the zeolites, which can be recovered through MW-assisted regeneration at 350 °C. Moreover, the MW-assisted TSA assured an energy and purge gas saving up to 63% and 82.5%, respectively, compared to a traditional regeneration process, resulting in effective process intensification