Decomposition of ferrihydrite prepared from Fe(NO3)3 aqueous solutions under varying pH

Aqueous solutions of Fe(NO3)3 were subjected to precipitation at 20°C and pH in the range 2.9–8.14, at constant pH and temperature. The precipitates contained CO2−3 and NO−3 anions bound in the sample structure. It was found that the TG, DTA, DTG and evolved gas analysis (EGA) curves depend significantly on the pH of preparation of the ferrihydrite.