Oxidative decolorisation of Eriochrome Black T with Chloramine‐T: kinetic, mechanistic, and spectrophotometric approaches

Abstract

The kinetics and mechanism of oxidative decolorisation of Eriochrome Black T (EBT) with sodium N‐chloro‐p‐toluenesulfonamide or Chloramine‐T (CAT), catalysed by osmium tetroxide [Os(VIII)] in alkaline medium and uncatalysed in acid medium, have been spectrophotometrically investigated at 303 K. The reaction exhibited a first‐order dependence of rate on [CAT]0 and [EBT]0 in both media, and also with respect to [H+]. The order with respect to [OH‐] and [Os(VIII)] was fractional. Activation parameters were deduced. It was observed that the uncatalysed decolorisation reaction was ca. eightfold faster in acid medium in comparison with alkaline medium, while the Os(VIII)‐catalysed reaction was ca. sevenfold faster than the uncatalysed reaction. Mechanisms and rate laws were determined. The chemical oxygen demand of Eriochrome Black T dye was also determined. Importantly, the developed oxidative decolorisation method is simple, efficient, inexpensive, requires less time, and is environmentally benign. Hence, it can be adapted for treating Eriochrome Black T present in industrial and laboratory wastewater.

Keplerate {Mo132}–Stearic Acid Conjugates: Supramolecular Synthons for the Design of Dye-Loaded Nanovesicles, Langmuir–Schaefer Films, and Infochemical Applications

“…For the ensembles of synthons with encapsulated ErChB, there is an 11.8% decrease in absorbance. Although the kinetics indicates the stability of the ensembles, the decrease in absorbance at 453–455 nm is predominantly due to the gradual decomposition of ErChB in aqueous media . Furthermore, the decomposition of dye can be accelerated by the giant POM under visible light. , …”

“…Although the kinetics indicates the stability of the ensembles, the decrease in absorbance at 453−455 nm is predominantly due to the gradual decomposition of ErChB in aqueous media. 46 Furthermore, the decomposition of dye can be accelerated by the giant POM under visible light. 47,48 Using TEM, the morphology of the dye-encapsulated ensembles was determined.…”