INVESTIGADORES
ROJAS DELGADO Ricardo
congresos y reuniones científicas
Título:
Intercalation of metallic EDTA complexes in Ni-Zn layered hydroxysalts
Autor/es:
RICARDO ROJAS; CRISTOBALINA BARRIGA; M. ÁNGELES ULIBARRI; VICENTE RIVES
Lugar:
Clermont-Ferrand
Reunión:
Conferencia; 13th International Symposium on Intercalation Compounds; 2005
Resumen:
Intercalation compounds are of great interest as precursor of catalysts, nanophase composites, etc. Ni-Zn Layered HydroxiSalts (Ni-Zn-LHSs) are anionic exchangers based on a brucite-like structure where one quarter of the divalent cation (Ni2+) have been removed from the octahedral holes and two Zn2+ cations tetrahedrally coordinated are stabilized just below and above one empty octahedral site, which leads to the excess positive charge [1, 2]. The general formula of these compounds can be represented as Ni1-xZn2x(OH)2Xm-x/m·nH2O. In recent years great attention has been paid to anionic exchangers containing metallic chelates in the interlayer [3]. They have been proposed as precursors for materials containing metallic nanoparticules, semiconductors, or metallic oxides with catalytic activity [4, 5]. EDTA is a polyprotic acid containing four carboxylic acid groups and two amine groups with lone pair electrons and it can complex or chelate metallic cations, acting as hexadentate ligand. It is used as sequestering agent in the food industry and has environmental implications as it can form stable complexes with heavy metal cations, increasing their solubility. EDTA chelates intercalation in Ni-Zn-LHSs allows the incorporation of new metal cations to the formula of these solids increasing their variability and their applications in catalysis. In this work Ni-Zn layered hydroxysalts containing acetate (LHS-[Ni-Zn]) has been prepared by a coprecipitation method and exchanged with M2+-EDTA complexes (M2+=Cu2+, Cd2+ and Mn2+). Synthesis conditions are studied and optimal samples are selected for their structural characterization and morphological study. Thermal decomposition of the different samples has been performed and the resulting products were also characterized. [1] Yamanaka, S., Ando K., Ohashi, M., Mater. Res. Soc. Symp. Proc., 371 (1995) 131. [2] Rojas, R., Barriga, C., Ulibarri, M. A., Malet, P., Rives, V., J. Mater. Chem. 12 (2002) 1071. [3] Tsyganok, A. I., Suzuki, K., Hamakawa, S., Takehira, K., Hayakawa, T., Chem. Lett. 1 (2001) 24. [4] Tsyganok, A. I., Suzuki, K., Hamakawa, S., Takehira, K., Hayakawa, T., Catal. Letters 1-3 (2001) 75. [5] Kaneyoshi, M., Jones, W., Mol Cryst. Liq. Cryst. 356 (2001) 459.