Entity

Time filter

Source Type


Iglesias L.,Rovira i Virgili University | Iglesias L.,Emas Research Center En Ingenieria Of Materiales cro Nano Sistemas | Alvarez M.G.,Rovira i Virgili University | Alvarez M.G.,Emas Research Center En Ingenieria Of Materiales cro Nano Sistemas | And 5 more authors.
Applied Clay Science | Year: 2014

Improving the adsorption of long-term radioactive species in the underground disposal of waste waters from nuclear reactors is a key issue. The natural metal oxides or hydroxides underground have the low retention ability of anionic species. Here, calcined Mg/Al LDHs were used as adsorbents. The influence on the adsorption capacity of different intercalated guest anions (carbonate (CO3 2-) and nitrate (NO3 -)) in the parent LDH was investigated, along with the effect of ultrasonication. Two Mg/Al molar ratios (3/1 and 2/1) were compared. Adsorption capacity was strongly affected by material textural properties, and the carbonate LDH-derived mixed oxides showed the largest adsorption capacity. Mixed oxides with an Mg/Al molar ratio equal to 3 presented higher iodide adsorption due to their lower charge density. The adsorption assisted by ultrasound increased iodide removal efficiency by reducing internal diffusion limitation. Two models were used to determine adsorption capacity: Langmuir and Freundlich. The iodide adsorption was best fitted by the Langmuir equilibrium model. © 2014 Elsevier B.V.


Alvarez M.G.,Rovira i Virgili University | Alvarez M.G.,Emas Research Center En Ingenieria Of Materiales cro Nano Sistemas | Frey A.M.,University Utrecht | Bitter J.H.,University Utrecht | And 5 more authors.
Applied Catalysis B: Environmental | Year: 2013

Bulk and carbon nanofiber supported MgAl hydrotalcites have been investigated as solid base catalysts for the synthesis of glycerol carbonate and dicarbonate and for the self-condensation of acetone. The supported materials exhibited a 300 times higher activity compared to bulk activated hydrotalcites for the transesterification. The materials could be reused while maintaining a high yield of glycerol carbonate. The activity of the mixed oxide, i.e., hydrotalcite materials after high temperature activation was considerably higher than both gas-phase and liquid phase rehydrated samples for the glycerol reactions. In contrast in the acetone self-condensation reaction the rehydrated samples were more active. This indicates that the polarity of the catalyst related to the reactant properties has a huge impact on the performance of a solid base catalyst. © 2013 Elsevier B.V.

Discover hidden collaborations