Surfactant-assisted synthesis of pure calcium carbonate nanoparticles from Sri Lankan dolomite

Abstract

Sri Lanka is rich in extensive deposits of dolomitic marbles with large quantities, which have not yet been exploited on an industrial-scale to produce value-added products such as precipitated calcium carbonate (PCC) nanoparticles. PCC is used extensively and is imported by Sri Lankan industries for application as a filler and extender. Hence, this work attempts to examine Sri Lankan impure dolomitic marbles as a source for the synthesis of pure PCC nanoparticles, so as to fulfill the current industrial demand and to add value to the cheap and mundane marbles. As reported in this paper, the calcium (Ca) components of the marbles can be extracted from impurities by preparing solutions of saturated calcium hydroxide, calcium citrate, Ca2+-ethylenediaminetetraacetic acid complexes and calcium sucrate, separately from dolomite. PCC nanoparticles are then synthesized by adding sodium carbonate to each calcium extract. The results shows that the best extract to synthesize PCC nanoparticles with high yield and purity is calcium sucrate. Here, calcium sucrate has been used for surfactant assisted hydrothermal synthesis of PCC nanoparticles with particle sizes ranging from 38.9 - 51.6 nm, which is a novel effort. This method could be applied to manufacture PCC nanoparticles on an industrial-scale.