26 documents found, page 1 of 3
Evolution of porosity of activated carbon fibres prepared from pre-oxidized acr...
Carrott, P.J.M.; Ribeiro Carrott, M.M.L.; Correia, P.F.M.M.Industrially pre-oxidized acrylic fibres were used to prepare activated carbon fibres (ACF). The results obtained show that pre-oxidation was effective in increasing the carbon yield during carbonization and reducing the reactivity of the char with CO2 during activation, making it possible to obtain ACF with high pore volumes, up to 1.15 cm3 g−1, with BET area of 2064m2 g−1, even without a prior laboratory stab...
Using Different Co-Adjuvant Activating Agents to Improve Activated Carbon Adsor...
Cansado, I.P.P; Mourão, P.A.M.; Ribeiro Carrott, M.M.L.; Carrott, P.J.M.Activated carbon (AC) has proved to be an effective adsorbent for the removal of an assortment of organic and inorganic pollutants from aqueous or gaseous media. However, the pursuit for more effective and cheaper AC is still very active and a diversity of textural and chemical treatments are described as a way to expand their applications. It is well known that the surface area and surface chemistry of AC stro...
Carbon aerogels used in carbon dioxide capture
Marques, L.M.; Carrott, P.J.M.; Ribeiro Carrott, M.M.L.In this work the maximum carbon dioxide adsorption capacity of carbon aerogels, obtained by a sol-gel process using 2,4-dihydroxybenzoic acid/formaldehyde (DHBAF) and resorcinol/formaldehyde (RF) as precursors, was studied. The effect of increasing the temperature of carbonization and physical activation of the samples DHBAF was also studied. The results showed that the maximum adsorption capacity is favoured a...
Porosity in ion-exchanged and acid activated clays evaluated using n-nonane pre...
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Carrott, P.J.M.; Russo, P.A.; Castilho, P.; Fernandes, C.; Catrinescu, C.; Breen, C.The applicability of the n-nonane pre-adsorption method for characterising the porosity in clays is presented. Na-SD, a Naþ-exchanged purified bentonite, and materials obtained by Al3þ-exchange and acid treatments of Na-SD and SAz-1 were used. Nitrogen adsorption isotherms, at 196 C, were determined before and after n-nonane pre-adsorption on each of the samples. In all materials, n-nonane remained adsorbed in ...
Selective methoxylation of limonene over ion-exchanged and acid-activated clays
Catrinescu, C.; Fernandes, C.; Castilho, P.; Breen, C.; Ribeiro Carrott, M.M.L.; Cansado, I.P.P.In this study, we report the use of clay-based catalysts in the methoxylation of limonene, for the selective synthesis of terpinyl methyl ether. Na-SAz-1, Ca-SWy-2 and Sap-Ca source clays and a montmorillonite (SD) from Porto Santo, Madeira Archipelago, Portugal were modified by (i) ion-exchange with Al, Fe, Ni and Na and (ii) acid activation, to produce catalysts with markedly different acidic and textural pro...
Adsorption of MCPA on different activated carbons
Mourão, P.A.M.; Cansado, I.P. P.; Ribeiro Carrott, M.M.L.; Carrott, P.J.M.Pesticides play an important role in the success of modern farming and food production but their use increases the residue levels in soils and waters and has been a public concern because of the potential risk to human health and the environment. Pesticides are generally applied in larger amounts than those needed for the pest control and they are swept away by transport processes such as leaching. Liquid phase...
Using different AC to improve MCPA removal from liquid phase
Cansado, I.P.P.; Mourão, P.A.M.; Ribeiro Carrott, M.M.L.; Carrott, P.J.M.The work presented here focuses on the adsorption of MCPA on a series of ACs prepared from recycled PET or cork via different activation methods. All ACs were characterised by nitrogen adsorption at 77 K and by elemental analysis. The adsorption isotherms of MCPA were determined on selected ACs, where the same amount of AC was added to flasks containing equal volumes of aqueous solutions with different initial ...
Catalisadores derivados de uma argila do Porto Santo: efeito da ativação ácida ...
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Russo, P.A.; Carrott, P.J.M.; Catrinescu, C.; Castilho, P.; Fernandes, C.; Breen, C.No âmbito de um projeto de investigação em curso (PTDC/CTM-CER/121295/2010), materiais derivados de argilas, de várias proveniências e submetidas a diferentes tratamentos de modificação, estão a ser usados como catalisadores em várias reações de interesse, como, por exemplo, na metoxilação do limoneno e na conversão do glicerol. Uma das possíveis vantagens, face a outros catalisadores alternativos, relaciona-se...
Adsorption and pre-adsorption for the detailed characterisation of clay catalysts
Ribeiro Carrott, M.M.L.; Cansado, I.P.P.; Carrott, P.J.M.; Castilho, P.; Catrinescu, C.; Fernandes, C.; Breen, C.Ion exchange and acid activation are easy and appropriate modification treatments for obtaining versatile clay derived catalysts which can be tailored for a precise reaction of interest. Depending on the specific conditions and also on the nature of the starting clays, the alterations in the porosity and the surface chemistry that occur can be determinant for the catalytic performance, in particular for selecti...
CO2 capture by amine impregnated carbon aerogels
Marques, L.M.; Carrott, P.J.M.; Ribeiro Carrott, M.M.L.In this work, CO2 adsorption/ desorption performance over carbon aerogels impregnated with amines of different molecular mass and structure, is reported.