Ferrihydrite gels derived in the Fe(NO3)3 · 9H2O–C2H5OH–CH3CHCH2O ternary system

A study of gel formation in iron(III) nitrate nonahydrate (Fe(NO3)3 · 9H2O)–ethanol (C2H5OH)–1,2-epoxypropane (propylene oxide (CH3CHCH2O)) ternary system has been performed. The phase boundaries for existing ferrihydrite gels were determined. It was shown that this ternary system has two different types of ferrihydrite gel phases. The dominant chemical bonds of these phases were investigated by Fourier transform infrared spectroscopy (FTIR). Both ferrihydrite phases transform to amorphous α-FeOOH phase after 6 h annealing at T = 300 °C. The temperatures of crystallization from these amorphous α-FeOOH phases to α-Fe2O3 phases were found.