I am synthesizing magnetite nano particles using Fe2+ and Fe3+ chloride salt and ammonium hydroxide. In the Fe2+ and Fe3+ solution, I immediately add NH4OH with vigorous stirring to produce magnetite nano particles. I test them using a magnet. As soon as I notice the particles are attracted to a magnet, I filter the solution.
My question, is it possible that my nano-particles are premature? Should I give the solution proper time before filtering it? This is because I am unable to get the desired quality of the particles.
Immad Amir
Nanoparticles exist in all phases, i.e. bulk phases. Thus, nanoparticles may be premature. It is important to allow sufficient time for the reaction before filtering the solution to ensure that you are producing particles with the desired quality. This time varies depending on the type of reaction and the concentrations of the reactants involved. It is useful to consult the literature on similar reactions to determine the optimal reaction time prior to filtration.
Dear Immad Amir,
please try to put the chlorides inside concentrated NH4OH to start the reaction at elevated pH. It will be better. You can try also with NaOH but you could have remaining Na ions.
Best regards.
Philippe.
Immad Amir
According to the theory of nucleation, atoms or molecules condense in the following sequence: condensation nucleus, clusters, nanoparticles, macroparticles. The rate of formation in this sequence slows down. However, in the early stages, it is large. To stop at nano size, it is necessary to stabilize the growth of nanoparticles by adding surfactants and polymers. In the case of magnetite, oleic acid is added. You don't, so your particles grow to a larger size.
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