Notice of RetractionDecolorization of Azo Dyes by Hydroponically Grown Sunflowers (Helianthus annuus L.)

Notice of Retraction

After careful and considered review of the content of this paper by a duly constituted expert committee, this paper has been found to be in violation of IEEE´s Publication Principles.

We hereby retract the content of this paper. Reasonable effort should be made to remove all past references to this paper.

The presenting author of this paper has the option to appeal this decision by contacting TPII@ieee.org.

Azo dyes are a source of water contamination in many parts of the world. All the dyes in common use are similar in having multiple aromatic rings conjugated together, with various substituents that alter the visible absorption spectrum. Plants normally deal with aromatic allelochemicals, and also do lignin synthesis and degradation reactions using peroxidases and laccases. Therefore, we are systematically investigating the abilities of hydroponically grown sunflowers to decolorize a wide range of azo dyes, at concentration 20 mg l^-1. Very different responses are obtained with dyes that have very similar structures. Although some azo dyes inhibited the growth of sunflowers, no symptom and adverse effect of sunflowers, which grown in 20 mg l^-1 azo dye solution, were observed. The decolorization rate and the pathways of declorization of the 7 azo dyes by sunflowers varied greatly. The maximum, minimum and average value of the decolorization rate of those dyes in 6 days was 100%, 33.2% and 77. The values for the apparent TSCF with sunflower for the 7 azo dyes varied greatly, from minimum 0.28 to maximum 1.05. The experiment showed that sunflowers can efficiently decolorize wastewater containing azo dyes.