Sonocatalytic Decolorization of Azo Dye by Ultrasound-Assisted Ytterbium-Substituted Mn2O3 Nanocatalyst

Ytterbium (Yb3+)-substituted nanocrystalline Mn2O3 (Mn2−xYbxO3) was obtained by oxidation of Mn(NO3)2 at ambient conditions under ultrasound sonication in basic solution. Yb3+ substitution into the structure of Mn2O3 resulted in a material with new physical properties, composition, and morphology. The SEM, XRD, EDX, TEM, HRTEM, XPS techniques were used for characterization of as-prepared material. Increasing the amount of Yb3+ ions during synthesis did not increase significantly the percent substitution in the final product beyond 6%. The influence of substitution of Yb3+ ions into Mn2O3 caused a red shift in the absorbance and a decrease in the band gap. The as-synthesized compounds were used for sonocatalytic degradation of tartrazine (TAZ). 4% Yb-doped Mn2O3 displayed the elevated sonocatalytic activity considering various amounts of ytterbium. The order of inhibitory effect of radical scavengers was 1,4 benzoquinone ˃ SO32− ˃ I− ˃ t-BuOH ˃ C2O42−. The influence of various specifications like catalyst amount, initial dye concentration, and ultrasonic power was explored.