Synthesis of magnesium hydroxide nanoparticles by spontaneous chemical reaction between aerosolized phases at room temperature conditions

A flameless method for the synthesis of nanoparticles at room temperature by coalescence of aerosolized droplets inducing a spontaneous chemical reaction between precursors is presented. The process is tested for the production of magnesium hydroxide nanoparticles at room temperature with an experimental setup based on pneumatic atomizers, condense collectors, mixers and a scrubber separator quenching the process of nanoparticle aggregation and collecting the final product in an aqueous dispersion recycled to the spray tower by a closed pressurized circuit. The solid phase is characterized for shape and composition by field emission scanning electron microscopy and for dimension by dynamic light scattering, with average diameters in a range of 29–62 nm. It has been proven that the quality of the final product depends, in order of decreasing influence, on the volume of the reaction chamber and on the concentration of the reagents in the aerosolized droplets. The process does not require the use of capping agents and/or surfactants aiming at damping particles aggregation and it allows obtaining an uncontaminated product whose composition makes it particularly attractive for specific applications where a high purity is needed, like biochemistry, pharmaceutics and theranostics. The mild operating conditions, the low energy demand and relatively low cost of the required equipment allow including this technique in the context of green, inherent safer and sustainable processes for nanoparticles synthesis.