Efficient decolorization of typical azo dyes using low-frequency ultrasound in presence of carbonate and hydrogen peroxide

Tongqian Zhao; Peng Li; Chao Tai; Jiaping She; Yongguang Yin; Yong'an Qi; Guocheng Zhang

doi:10.1016/j.jhazmat.2017.12.009

Efficient decolorization of typical azo dyes using low-frequency ultrasound in presence of carbonate and hydrogen peroxide

J Hazard Mater. 2018 Mar 15:346:42-51. doi: 10.1016/j.jhazmat.2017.12.009. Epub 2017 Dec 7.

Authors

Tongqian Zhao¹, Peng Li¹, Chao Tai², Jiaping She¹, Yongguang Yin³, Yong'an Qi⁴, Guocheng Zhang⁴

Affiliations

¹ Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, China.
² Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, China; Collaborative Innovation Center for Coal-Bed Methane and Shale Gas of Henan, Jiaozuo 454000, China. Electronic address: taichao@hpu.edu.cn.
³ State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, 100085 China.
⁴ Institute of Resources and Environment, Henan Polytechnic University, Jiaozuo, 454000, China; Collaborative Innovation Center for Coal-Bed Methane and Shale Gas of Henan, Jiaozuo 454000, China.

PMID: 29247953
DOI: 10.1016/j.jhazmat.2017.12.009

Abstract

The aims of this study as to evaluate and understand the decolorization of azo dyes using carbonate and hydrogen peroxide under low-frequency ultrasonic irradiation. Under optimal conditions, the decolorization ratio of acid orange 8 (AO 8), a typical azo dye, was > 90% after 2 h of irradiation. The decolorization rate of AO 8 was 0.023 min^-1 under ultrasonic irradiation, which was about two times that without ultrasound. Different from the results of other published studies, OH played a minor role, while CO₃^- played the most important role in AO 8 ultrasonic decolorization in the presence of CO₃^2- and H₂O₂, with a contribution of 56.52%, followed by CO₄^2- (32.61%) and ¹O₂ (10.87%). Another difference is that CO₃^- formed through the cleavage of peroxymonocarbonate or peroxydicarbonate under ultrasonic irradiation rather than through reaction between hydroxyl radical and carbonate. Investigations for different azo dyes revealed that the decolorization rate decreased in the order AO 8 ≈ orange II > acid red 9 > acid yellow 11, probably because of molecular differences among the azo dyes.

Keywords: Azo dyes; Carbonate; Decolorization; Hydrogen peroxide; Ultrasound.

Publication types

Research Support, Non-U.S. Gov't