Effect of carbon nanomaterials on calcium carbonate crystallization

Abstract

The addition of the water-soluble carbon nanomaterials, fullerenol (C₆₀(OH)_n), hydroxylated single walled carbon nanotubes (HO-SWNTs) and isophthalic acid functionalized-SWNTs (IPA-SWNTs), alter the morphology and crystal phase of CaCO₃ precipitates form aqueous solution. CaCO₃ precipitation in the presence of C₆₀(OH)_n results in the formation of spherical features, 5-pointed flower shaped clusters, and triangular crystals as opposed to the usual rhombic crystals. In addition, the meta-stable vaterite phase is observed with the addition of C₆₀(OH)_n. The effect on crystal growth of the C₆₀(OH)_n is not a simple function of the pH of the solution, although it may be due to reactivity of the hydroxyl groups. Precipitation with water-soluble HO-SWNT and IPA-SWNTs produces CaCO₃ coated SWNTs with the CaCO₃ being amorphous rather than crystalline.