Hydrolytic Formation of Submicron Iron(III) Oxides from Dilute Ferric Nitrate Solutions1
- Xin-Yun Gu and
- Pa Ho Hsu2
Two series of 0.001 M Fe(NO3)3 solutions, having NaOH/Fe molar ratios ranging from 0 to 3.1, were prepared by diluting a 0.5 M Fe(NO3)3 stock solution with water followed by hydrolysis at 70°C. The preparations differed only in the initial temperature of the water for dilution, but the final products were very different in particle size, morphology, and crystallinity. In Series I solutions, prepared with 70°C water, the reaction products were amorphous, structureless masses initially (1 d), but became well-crystallized goethite and/or hematite in the shape of rods or plates shortly after being aged at 70°C. In Series II solutions, prepared with room temperature water, the hydrolyzed products were tiny spheres having a well-defined outline and homogeneous size throughout the experiment. They were very poorly crystallized goethite and/or hematite even after 248 d of aging at 70°C, as characterized with a high power rotating anode x-ray diffractometer. The results suggest that the temperature of water for solution preparation plays a key role in the size and nature of the initial hydrolytic product that, in turn, played a key role in the rate of redissolution and recrystallization.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
Copyright © .