Ultrasound assisted synthesis of yellow rare earth cerium zinc molybdate anticorrosion nanopigment is presented. This new class of pigment is eco-friendly alternatives to lead, cadmium and chromium pigment as these pigments contains carcinogenic species like Cr(6+) which is responsible for human disease. The synthesis of nanosized cerium zinc molybdate was carried out using cerium nitrate, sodium zinc molybdate as a precursor materials by conventional and ultrasound assisted chemical precipitation method without addition of emulsification agent. XRD, FTIR and elemental analysis confirm the formation of cerium zinc molybdate nanoparticles. The conductivity results indicate that conventional synthesis takes longer time, while in sonochemical technique (US), reaction completes within short period of time. Improved solute transfer rate, rapid nucleation, and formation of large number of nuclei are attributed to presence of cavitation. Saturation of the Ce(3+) ions reaches earlier in case of sonochemical technique which restricts the growth of particles hence smaller size is obtained. The crystallite size of cerium zinc molybdate was found to be 27nm from XRD analysis.

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In the present work, sodium zinc molybdate (SZM) nanoparticles were prepared using conventional and an innovative ultrasound assisted co-precipitation of sodium molybdate, zinc oxide and HNO3 at different temperatures. Prepared product was characterized by XRD, TEM, FT-IR, particle size distribution (PSD), TGA and DTA techniques. TEM analysis shows the spindle-shaped morphology of the formed SZM nanoparticles. The average particle size of SZM nanoparticles is found to be lower in case of sonochemical method (78.3 nm) compared to conventional method (340.2 nm) which is attributed to faster solute transfer rate due to ultrasonic irradiation leading to rapid nucleation and restricted growth of SZM nanoparticles. Further, the kinetics of synthesis of SZM nanoparticles are studied using the sonochemical method at different operating temperature and conventional method at 80°C. It is shown that the rate of reaction is significantly faster at 40°C compared to other temperatures and also conventional method. This can be attributed to intense cavity collapse at lower temperature (low vapour pressure) compared to higher temperature (high vapour pressure) of the reaction mixture.