Simone Cavenati

Universidade da Madeira | UMA · Centro de Química da Madeira - ISOPlexis

In natural environment, plants are exposed to constant biotic and abiotic stresses (including exposure to trace metals) which may unbalance their equilibrium. As a result, plants have developed important defense mechanisms as, for instance, the production of low molecular weight thiols such as cysteine (Cys) and reduced glutathione (GSH). Much effo...

Minocycline, oxytetracycline, tetracycline, enrofloxacin and ceftiofur, commonly used veterinary pharmaceuticals, were searched in four urban, two livestock and two slaughterhouse effluents from wastewater treatment plants (WWTPs) in the north of Portugal. A simple method that includes solid-phase extraction followed with analysis by high-performan...

Removal of nitrogen from methane-rich streams is one of the most energy-intensive gas separations. Nitrogen rejection units are very expensive units and in streams with small and intermediate flowrates, adsorption technologies proved to be an economic alternative, if N2 is selectively adsorbed in the adsorbent. In this work we have synthesized sodi...

The discovery of new materials with enhanced selectivity or capacity will boost adsorption applications, especially for environmental control. In particular, it was mentioned that metal-organic frameworks (MOF) with different tailored properties may be prepared for desired separations. To promote industrial application of MOF materials, up-scaling...

A vacuum pressure swing adsorption (VSA-PSA) process is studied for the removal of carbon dioxide in a contaminated stream of natural gas to achieve fuel grade methane. The adsorbent used was zeolite 13X (CECA) where CO2 is strongly adsorbed. A Skarstrom-type cycle comprising pressurization with product, feed, countercurrent blowdown, and countercu...

A novel compact adsorption-based process for removal of carbon dioxide and nitrogen from low and medium natural gas flowrates is discussed. The layered pressure swing adsorption (LPSA) process studied is composed of a zeolite 13X to selectively remove carbon dioxide followed by a layer of carbon molecular sieve 3K to make the separation of nitrogen...

One of the developments in separation technologies by adsorption is the use of new shaped structured materials offering some attractive properties rather than pellet or extrudates behavior. Monolithic adsorbents have actually been studied in a wide range of applications. It is the purpose of this work to report the behavior of a square honeycomb mo...

Adsorption equilibrium of methane and nitrogen on CMS 3K from Takeda Corp. were gravimetrically measured at 298, 308, and 323 K and at pressures up to 2000 kPa. The most adsorbed gas is methane followed by nitrogen. The adsorption loading at 550 kPa and 308 K is 1.73 mol/kg for methane and 0.91 mol/kg for nitrogen. Experimental data were fitted wit...

This work focuses on the production of pipeline grade methane from landfill gas (LFG). Vacuum pressure swing adsorption technology using a kinetic adsorbent, Carbon Molecular Sieve 3K (Takeda), was employed for the separation of methane−carbon dioxide mixture. Adsorption equilibrium and kinetics of methane and carbon dioxide are reported at 298, 30...

The use of vacuum pressure swing adsorption (VSA-PSA) with carbon molecular sieves (CMS) as selective sorbents is evaluated as an alternative technology for methane−nitrogen and propane−propylene separations. The larger molecules, methane and propane, are very low-diffusing species, resulting in processes where nitrogen and propylene are retained i...

In this paper we discuss the performance of Layered PSA (Layered Pressure Swing Adsorption) for methane/carbon dioxide/nitrogen separation for methane upgrading from contaminated natural gas. A four-step PSA cycle was defined using extrudates of zeolite 13X (selective for carbon dioxide) and CMS 3 K (nitrogen selective) in a layered packed bed. Ter...

The members of the MERCOSUR as well as the European Union have agreed in the Kyoto protocol to diminish 12% the emissions of carbon dioxide up to 2010. Carbon dioxide emissions are quite high in the entire European continent with many countries being in the top 20 larger polluting countries of the world. Co-generation of electricity and heat has pr...

Methane is an environmental friendly fuel. The main source of methane is natural gas. Despite the presence of other heavier hydrocarbons, methane is contaminated with undesired impurities such as nitrogen and carbon dioxide that have to be removed for fuel usage. Carbon dioxide may be up to 17% (%mol) in natural gas and nitrogen contamination can b...

New adsorbents were prepared and tested for the separation of propane-propylene mixtures by adsorption. The ordered mesoporous material SBA-15 was used as the starting material for silver-ion deposition for pi-complexation with propylene. Two different loadings of silver were evaluated. Adsorption equilibrium and kinetic measurements of propane and...

High-pressure adsorption of methane, carbon dioxide, and nitrogen on zeolite 13X was measured in the pressure range (0 to 5) MPa at (298, 308, and 323) K and fitted with the Toth and multisite Langmuir models. Isosteric heats of adsorption were (12.8, 15.3, and 37.2) kJ/mol for nitrogen, methane, and carbon dioxide respectively, which indicate a ve...

New adsorbents were prepared and tested for the separation of propane-propylene mixtures by adsorption. The ordered mesoporous material SBA-15 was used as the starting material for silver-ion deposition for pi-complexation with propylene. Two different loadings of silver were evaluated. Adsorption equilibrium and kinetic measurements of propane and...

Tese de mestrado. Engenharia Mecânica. Faculdade de Engenharia. Universidade do Porto. 1998