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

ABSTRACT

The 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.

KEYWORDS:

• Ultrasound
• degradation
• kinetics
• rare earths

Acknowledgments

The author is grateful to Prof. Ashok Kumar, University of Melbourne, Australia for immense help in the technical discussion prior to article submission and to DAE-BRNS for the financial support. PKP is also grateful to BRNS for the award of SRF and CSIR-NIO for analytical support.