Materials Research Bulletin, Vol.47, No.3, 677-682, 2012
Detailed characterization of calcium silicate precipitation tube (CaSPT) as a multi-cation adsorbent in aqueous medium
Calcium silicate precipitation tube (CaSPT) produced through 'silica garden' route has been physicochemically characterized as a multi-cation adsorbent in aqueous medium. Characterizations include phase identification, morphology, surface area, pore volume, iso-electric point and surface charge determination, thermogravimetric analysis, functional group identification and initial assessment as a multi-cation adsorbent. These tubes are hierarchically built from smaller interconnected tubes of about 20 nm diameter. Exterior and interior walls of the 'as grown' tubes, analyzed through SEM-EDAX, show different chemical composition. One of the prominent phases in 'as grown' tubes was identified as gamma-Ca2SiO4. CaSPT has moderately high surface area. Iso-electric point (IEP) at pH 3.41 indicates the surface is suitable for adsorbing cationic species. Initial adsorption studies corroborate that CaSPT is a promising adsorbent for Cu(II), Cd(II), Zn(II), Pb(II) and Cr(III). CaSPT as an adsorbent is superior to conventional non tubular calcium silicate. (C) 2011 Elsevier Ltd. All rights reserved.
Keywords:Nanostructures;Chemical synthesis;Electron microscopy;Thermogravimetric analysis;Surface properties