[Study on decolorization of triphenylmethane dyes by DTT].

Decolorization of triphenylmethane dyes by DTT was researched. For malachite green, content of DTT in reaction system was optimized to investigate the quantitative relation between DTT and malachite green and the decolorization capacity of DTT was confirmed. Effect of pH of reaction system on reducibility of DTT was explored. The results indicated 4 mol malachite green could be decolorized by 1 mol DTT averagely within 1 min, when pH of the reaction system was above 5. The decolorization rate was up to 97%. Decolorization product of malachite mreen was corroborated to be its leuco form by HPLC analysis. Some insoluble compounds, which could be the complex products of leuco malachite green with DTT, were formed during the decolorization reaction. Decolorization of crystal violet, brilliant green and basic fuchsin by DTT was tested further, and the decolorization rates were all above 85%, which suggested DTT was a broad-spectrum decolorization agent for triphenylmethane dyes.