TEXTURAL AND MORPHOLOGICAL CHARACTERIZATION OF COPPER(II)-EXCHANGED ROMANIAN CALCIUM BENTONITE
ANA-MARIA GEORGESCU 1, 2, GHEORGHE BRABIE 3, ILEANA DENISA NISTOR 1, CLAUDE PENOT 2, FRANÇOISE NARDOU 2 1. “Vasile Alecsandri” University of Bacau, Faculty of Engineering, Chemical and Food Engineering Department, 157 Calea Marasesti street, 600115, Bacău, Romania
2. University of Limoges / CEC, SPCTS, UMR 7315 CNRS, 12 Rue Atlantis, 87068, Limoges Cedex, France
3. “Vasile Alecsandri” University of Bacău, Faculty of Engineering, Managerial and Technological Engineering Center of Research, 157 Calea Mărăşeşti street, 600115, Bacău, Romania
Romanian calcium bentonite was modified by copper(II) ion-exchange, by varying the copper precursors (chloride, sulphate) and synthesis parameters (pH, temperature, time). The quantification of the Cu(II) ions was carried out by atomic absorption spectrophotometer. The modified bentonites were characterized by textural analysis (specific surface area by the Brunauer-Emmett-Teller method (BET) and by nitrogen adsorption/desorption isotherm), structural composition (X-ray diffraction (XRD)) and morphological analysis (scanning electron microscopy (SEM)). Analysis of the nitrogen adsorption/desorption isotherm shows that ion exchanged bentonites, not only contain mesopores, but micropores in larger quantities too. The values of the specific surface area increased by about 20 m2/g compared with raw bentonite, but the interlamellar distance values do not vary substantially. Scanning electron micrographs were acquired to demonstrate changes in the texture of the clay before and after ion exchange.
