Nucleation, growth and aggregation are important processes in the environment involving nanoparticles. In this work, we studied the formation and aggregation kinetics of akaganeite nanoparticles during thermal hydrolysis of FeCl3 solutions (0.02, 0.2, and 0.8 M) at various temperatures (50 � 80 oC) using in-situ small angle X-ray scattering (SAXS). Results showed that particle size increased dramatically with time and the growth kinetics strongly depended on the temperature. After a certain reaction time, developing particles in the 0.2 M solutions suddenly assembled to form periodic aggregate structures with inter-particle distances of 20 - 30 nm, as shown by the presence of pronounced diffraction peaks at several small angles. Each inter-particle distance slightly increased with reaction time, implying growth of nanoparticles. The texture indicated by 2-D diffraction images suggests the presence of preferred orientation of assemblies. This phenomenon was observed in neither 0.02 M nor 0.8 M FeCl3 solutions, indicating its concentration dependence.

Study of formation and aggregation of akaganeite nanoparticles using In situ small angle X-ray scattering

243rd National Meeting (2012)

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