Removal of cobalt, europium, cerium, strontium and copper by Fe2O3 and Fe3O4 particles from aqueous solutions

Abstract

Fe2O3 and Fe3O4 oxides are promising materials for removal of heavy metals and radionuclides from
water. The purpose of this paper is to study the influence of pH on efficiency of metal removal and to
determine the sorption capacity of Fe2O3 and Fe3O4 with respect to cerium, europium, and copper. Fe2O3
particles were obtained by thermal annealing (450°С) of preliminary precipitated iron (III) hydroxide from
iron salts at pH 9; Fe3O4 particles were obtained by precipitation of iron hydroxides from FeCl3 and FeSO4 in
the ratio 2:1 at pH 9. The values of specific surface area were 150 m2/g and 130 m2/g for Fe2O3 and Fe3O4,
respectively. It was established that iron oxide particles remove europium, cerium, and copper most
effectively (the extent of removal 92-97%) in the pH range 4-9. The efficiency of removal of cobalt and
strontium grows with increasing pH and reaches maximum values at pH 9. Obtained oxides are characterized
by the following values of the sorption capacity at pH 5: europium 21.3 mg/g, cerium 9.2 mg/g, copper 15.7
mg/g – for Fe2O3; europium 19.7 mg/g, cerium 7.5 mg/g, copper 11.6 mg/g – for Fe3O4.