Electrospray of ionic precursor solutions to synthesize iron oxide nanoparticles: Modified scaling law

Existing scaling laws for electrosprays are based on particle precursors that do not affect the conductivity of the solution. A generalized scaling law for size of resultant particles obtained from electrospraying ionic precursor solutions is developed. Two different scaling expressions are derived for weak and strong electrolyte solutions based on Arrhenius expression and Kohlrausch's empirical law, respectively. The modified scaling laws are verified by comparing measured size distributions of the resultant electrosprayed aerosols generated by electrospraying aqueous and ethanol solution of ferric nitrate. The second aspect of the work is to demonstrate that narrow size distribution, nanosized iron oxide particles can be produced by thermally decomposing the resultant electrosprayed iron nitrate precursor particles. Tests were conducted in a furnace aerosol reactor (FUAR) over a range of temperatures 293–1173 K. Iron oxide particles in the range of 6–40 nm with geometric standard deviation between 1.1 and 1.3 were obtained as end product.