Solid-solid crosslinking of carboxymethyl cellulose nanolayer on titanium oxide nanoparticles as a novel biocomposite for efficient removal of toxic heavy metals from water.

Nano titanium oxide (Nano-TiO2) was used in this work as a solid support to solid-solid immobilize carboxymethyl cellulose via glutaraldehyde as an efficient cross linking reagent to produce a novel nanosized biocomposite (Nano-TiO2-glu-CMC). The synthesized materials were characterized by FT-IR to confirm crosslinking reaction between the two species as well as by HR-TEM, SEM, TGA and surface area analysis. The particle size was found to correspond to 22.2-44.4nm for Nano-TiO2-glu-CMC. The designed nanosized biocomposite was used and compared with Nano-TiO2 for separation and extraction of heavy metal ions such as Cd(II), Pb(II) and Hg(II) from aqueous solution by using batch experiment and microcolumn technique. The maximum metal sorption capacity values of Cd(II), Pb(II) and Hg(II) were established as 2440μmolg-1 (pH 7), 2880μmolg-1 (pH 6) and 1160μmolg-1 (pH 3), respectively. Optimization of the extraction experiments confirmed the maximum adsorption upon using 0.025g biocomposite dosage and 30min contact time.