Characterization of CaCO3 Nanoparticles Synthesized by Reverse Microemulsion Technique in Different Concentrations of Surfactants

Calcium carbonate nano-particles were synthesized by a reverse micro-emulsion method at room temperature with tween® 80 and span® 80 as co-surfactants. the nano-particles synthesized were surface modified by stearic acid. an important operating variable in the span 80-tween 80/toluene/water reverse micro-emulsion system, the ?-value (water/surfactant molar ratio) was investigated. the material was characterized by sem, tem, x-ray diffraction (xrd), ft-ir, uv-vis and tga/dta techniques. the size of the nano-particles was determined by tem as well as xrd data for various concentrations of surfactants. the results showed that the size of the nano-particles was influenced by the concentration of the surfactants in the micro-emulsion system. the xrd analysis at room temperature showed single phase formation of calcite. ft-ir confirmed the formation of calcite with characteristic absorption bands observed at 712, 881 and 1460 cm-1, corresponding to ?4, ?2, and ?3 modes of co3-2 absorption bands of calcite. the results of the uv-vis spectrophotometric analysis indicated that the calcite (caco3) is an indirect gap material [(5.60 ev (30 wt.% surfactant), 5.40 ev (36 wt.% surfactant) and 5.36 ev (42 wt.% surfactant)] at room temperature.