Study on H2O2/TAED and H2O2/TBCC bleaching mechanism related to hydroxyl radical with a fluorescent probe.

The generation of hydroxyl radical (HO*) in H2O2/TAED and H2O2/TBCC systems for cotton fabric bleaching was proved and detected with a novel fluorescent probe benzenepentacarboxylic acid (BA). Effect of HO* generation on the cotton fabric bleaching performances was further discussed. The results show that HO* yield in H2O2/TAED and H2O2/TBCC systems was respectively about 11 and 15 times higher than that in H2O2 system without activators under the same alkali condition. Meanwhile, TAED and TBCC apparently promoted fabric whiteness and H2O2 decomposition rate. As the addition of HO* scavenger dimethylsulfoxide (DMSO), fabric whiteness decreased while tensile strength increased. It proves that HO* played a significant role in H2O2/TAED and H2O2/TBCC bleaching. Two main bleaching routes were suggested. The present work brought new insight into H2O2/TAED and H2O2/TBCC bleaching mechanism. It is quite instructive to develop efficient and ecological bleaching processes.