Organically modified superhydrophobic CaCO3, CaCO3 : La3+ and CaCO3 : Tb3+ – Synthesis, characterization, absorption and photoluminescence behaviour

Department of Chemistry, GITAM University, Visakhapatnam-530 045, Andhra Pradesh, India
E-mail : mscbabu@yahoo.com Fax : 91-891-2790032
Manuscript received online 20 June 2015, accepted 25 August 2015

Synthesis of superhydrophobic CaCO₃, CaCO₃ : La³⁺ and CaCO₃ : Tb³⁺ with complex morphologies under the influence of lauric acid in methanol medium was investigated. Lauric acid directed the transformation of thermodynamically stable broken sponge-like calcite CaCO₃ to ellipsoid-like vaterite. Further, flower shaped amorphous CaCO₃ : La³⁺ and CaCO₃ : Tb³⁺ resulted after doping the lanthanide elements to CaCO₃. The morphology, composition and phases of the synthesized compounds was characterized with scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR) and thermogravimetric analysis (TGA). Water contact angle of 140º indicates superhydrophobic behavior of lauric acid modified CaCO₃. More importantly, these materials also displayed high absorption for oils, dyes and genotoxic solvents such as xylene and toluene. The room temperature photoluminescence (PL) measurements of CaCO₃ : La³⁺ and CaCO₃ : Tb³⁺ showed emission at 484 nm (blue) and 545 nm (green), respectively.