Potentiation of hydrogen peroxide mediated water decontamination using thioglycolic acid

Abstract

There is an increasing interest in the development of metal-free catalysts for hydrogen peroxide (H2O2) based water decontamination. Thiols are well known reductants and react with oxidants via electron transfer mechanism. However, the effect of thiols on H2O2 based degradation remains uninvestigated. Herein, we reveal the potential of thiols such as thioglycolic acid (TGA), cysteine and glutathione to enhance H2O2 based degradation. The pseudo first order decolorization rate (k1) of Methylene Blue (MB) by H2O2 alone was 1.0 × 10−4 min−1, however, in the presence of thiols such as GSH, Cys and TGA, k1 of MB by H2O2 was increased to 26.9 × 10−4 min−1, 265.3 × 10−4 min−1, and 940.4 × 10−4 min−1, respectively. Furthermore, we demonstrate that TGA can drastically enhance H2O2 based oxidation for decolorizing a variety of dyes and to inactive bacteria as well. Nitroblue tetrazolium (NBT) assay revealed that the superoxide anion radical as primary reactive oxygen species in TGA/H2O2 oxidation system.