Sonochemical Synthesis of Aragonite‐Type Calcium Carbonate with Different Morphologies.

Abstract

Morphologies. -The title compound is synthesized for the first time by irradiating an aqueous solution containing stoichiometric amounts of CaCl2 and NaHCO3 with high-power ultrasound. The samples are characterized by XRD, FT-IR, and SEM. The morphology of the as-synthesized aragonite evolves from rod-shaped to spindle-shaped upon increasing the acoustic amplitude from 50 to 70% of the full amplitude. A possible mechanism for the controllable aragonite formation is proposed. This facile route to obtain uniform aragonite is suitable for large-scale industrial production. -(ZHOU, G.-T.; YU*, J. C.; WANG, X.-C.; ZHANG, L.

Removal of Pb(II) and Zn(II) from Aqueous Solutions by Raw Crab Shell: A Comparative Study

“…In order to explore the interactions between metal ions and CS, FTIR spectra of samples before and after uptake are recorded in the range of 400 to 4000 cm À1 , and are presented in Figure 7a. As for raw CS, the peaks at 711, 870 and 1430 cm À1 , attributable to CO 2À 3 (Zhou et al, 2004), would note the existence of a carbonate component in the biomaterial, while the amide II band at 1550 cm À1 and NH stretching band at 3272 cm À1 (Ifuku et al, 2009), are especially characteristic of anhydrous a-chitin. The characteristic peak at 1662 cm À1 indicates amide groups (-NHCO stretching), and the bands in range of 3300 to 3500 cm À1 are thought to represent the hydroxyl group, which might mean the presence of protein in CS.…”