Synthesis and Surface Modification of Calcium Carbonate Nanoparticles Using Ultrasound Cavitation Technique

Abstract

Calcium carbonate nanoparticles (nCaCO₃) was synthesized using optimized process of ultrasound assisted precipitation technique. Due to ultra-sonication phenomena, reacting components of reaction mixture gets dispersed uniformly, and at the same time nCaCO₃ particles agglomerate with each other due to strong electrostatic force of attraction developed over their surface. The de-agglomeration and charge nullification were achieved using surface modification of CaCO₃ nanoparticles using triethoxy vinyl silane (TEVS) under ultrasound environment. The surface modification of nCaCO₃ particles was confirmed using Fourier transforms infrared (FTIR) spectroscopy. Size, shape and formation of nCaCO₃ particles at nanoscale were studied using transmission electron microscopy (TEM). The size of unmodified and modified nCaCO₃ was found to be ≈50-80 and 50-90 nm, respectively, with square crystal structure morphology. Due to the surface modification by TEVS, thin layer was formed over the surface of nCaCO₃ particle, which was confirmed by TEM micrograph. The purpose behind carry out this reaction under ultrasound environment is to optimize synthesis procedure of nCaCO₃ particles, to provide effective ultrafine precipitation and give stable & uniform dispersion of inorganic particles with reactants. Moreover, the acoustic waves of ultrasound treatment are an effective controlling parameter to obtain uniform dispersion of inorganic nanoparticles in solution by producing non-linear effects in reaction mixture. In this ultrasound treatment, transient cavitation and acoustic stretching are the most dominant affecting parameters, which give homogeneous dispersion of nCaCO₃.