Enhanced biodecolorization of azo dyes by anthraquinone-2-sulfonate immobilized covalently in polyurethane foam

The effect of anthraquinone-2-sulfonate covalently immobilized in PUF (AQS-PUF) on the decolorization of azo dyes by Escherichia coli K12 was investigated. The results showed that AQS-PUF mediated biodecolorization rate of azo dye amaranth increased over 5-fold compared with that lacking AQS, and the kinetics of its biodecolorization could be described using Quiroga second order equation. During the above process, a lot of the cells of E. coli K12 were attached in the walls of AQS-PUF pores. After 10 repeated experiments using AQS-PUF, immobilized AQS-mediated biodecolorization efficiency of amaranth retained over 98.7% of their original value. Moreover, AQS-PUF could greatly enhance the decolorization rates of a broad range of azo dyes. These results indicated that AQS-PUF as a biocarrier exhibited high catalytic activity and good stability for potential applications.