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

Ytterbium (Yb 3+ )-substituted nanocrystalline Mn 2 O 3 (Mn 2−x Yb x O 3 ) was obtained by oxidation of Mn(NO 3 ) 2 at ambient conditions under ultrasound sonication in basic solution. Yb 3+ substitution into the structure of Mn 2 O 3 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 Yb 3+ ions during synthesis did not increase significantly the percent substitution in the final product beyond 6%. The influence of substitution of Yb 3+ ions into Mn 2 O 3 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 Mn 2 O 3 displayed the elevated sonocatalytic activity considering various amounts of ytterbium. The order of inhibitory effect of radical scavengers was 1,4 benzoquinone ˃ SO 3 2− ˃ I − ˃ t-BuOH ˃ C 2 O 4 2− . The influence of various specifications like catalyst amount, initial dye concentration, and ultrasonic power was explored.