Experimental and Kinetic studies on the combined influence of ultrasonication and rare earths on removal of azo dyes

ABSTRACTThe aim of the present study is to decolorize azo dyes containing (-N=N-) bonds such as Reactive Black 5 (RB 5), Basic Blue 3 (BB-3) and Disperse Blue 373 (DB 373) in the presence of ultrasound (US) and rare earth (RE), La+3, Ce+3, Pr+3 and Gd+3 ions in aqueous solutions. In the presence of US (20 kHz, 250 W) alone, these dyes, in the concentration range 8–144 ppm, were decolourized to different extents, RB5 (~20–17%); BB3 (~40–21%) and DB373 (~47–35%) at different time intervals. However, in combination US with REs, the removal was greater than 90%. The degradation followed pseudo-second-order kinetics.