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 physico-chemically 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 γ-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.

Calcium silicate precipitation tube (CaSPT) produced through ‘silica garden’ route is a promising adsorbent for heavy metal ions in aqueous medium.Figure optionsDownload as PowerPoint slideHighlights
► Calcium silicate precipitation tube (CaSPT) synthesized through ‘silica garden’ route undergoes dramatic changes in its surface properties over conventional calcium silicate.
► CaSPT(s) are hierarchically built from smaller interconnected tubes of about 20 nm diameter.
► CaSPT(s) are porous, have high surface area and comprise negative surface sites.
► CaSPT is a promising adsorbent for Cu(II), Zn(II), Cd(II), Pb(II) and Cr(III) in aqueous medium.