An inorganic-organic hybrid material made of a silica-immobilized schiffbase receptor and its preliminary use in heavy metal removal

A novel and excellent host for heavy metals was synthesized by chemical immobilization of a (E)-4-((pyridin-2-yl-methylene)amino)phenol Schiff base receptor onto silica particles. The new hybrid material (SPSB) was analyzed and evaluated by elemental analysis, FT-IR spectroscopy, solid-state 13C NMR, scanning electron microscopy, BET surface area and BJH analyses. The surface exhibits good thermal stability determined by thermogravimetry and good chemical stability examined in various acidic and buffer solutions (pH 1–7). The coordination ability of SPSB was found to be most efficient in the pH range 6.5–8 for Hg2+, Cd2+, Pb2+ and Zn2+. Alkali coexisting ions did not interfere with separation and determination. The adsorbent can be regenerated at ease without destruction. Heavy metal removal performance (99 mg g−1) was found to be higher compared to previous literature reports

Comparative sorption studies of chromate by nano-and-micro sized Fe2O3 particles

The comparative adsorption studies of Cr (VI) on nano and micro-powder Fe2O3 were investigated using kinetics and batch adsorption techniques. The uptake of chromate onto both the oxides of iron was observed to be dependent on the pH, contact time, temperature, media dosage and concentration of chromate anions. The values of sorption maxima were higher in the case of Fe2O3 nanopowder than the micro-powder which can be ascribed to the high surface area and point of zero charge (PZC) of the former oxide. The Dubinin-Radushkivech and Langmuir models were found well fitted for the description of the batch adsorption data. The FTIR studies confirmed that the hexavalent chromium was adsorbed onto both the iron oxides in the form of the Cr2O72−