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COMPARATIVE SPECTROSCOPIC AND ELECTROKINETIC STUDIES ON METHYLENE - BLUE ADSORPTION ON TO SAND AND BRICK FROM CENTRAL AFRICAN REPUBLIC
Authors: B. BAGOUA, E. FOTO, O. ALLAHDIN, M. WARTEL, J. MABINGUI & A. BOUGHRIET
Number of views: 484
Chemical properties of local sand and brick from Central African Republic were determined by using the
following techniques: ESEM/EDS, 1H, 23Na and 29Si MAS NMR, CHNS, and ICP-AES. From batch experiments, sand and
brick samples were tested for the adsorption of methylene blue (MB) in aqueous media. The experimental data were well
correlated by both the Langmuir and Freundlich models. Brick adsorbents were developed with better adsorption for the
removal of MB from aqueous solutions than sand. Hydroxylation and dealumination of the brick with HCl, followed by a
deposition of iron oxyhydroxide, significantly improved its MB adsorption capacity. Structural and morphological
characterization further proved that coated brick had better BET surface area and porosity than sand. Electrokinetic studies
on sand and brick samples confirmed that electrostatic interaction is indeed the potential mechanism contributing to the
enhanced MB adsorption on these adsorbents. Spectroscopic analyses showed that the enhanced adsorption capacity of
treated brick was intimately related to the generation of sodic surface sites: ≡S-O-Na+ (with S = Fe, Al, and Si) that favor
the uptake of a cationic dye like methylene blue via electrostatic forces at the solid – water interface.