The degradation of triazo dye chlorantine fast green BLL in aqueous solutions by gamma radiation—III

Abstract

The radiation degradation yield ( G d values) of Chlorantine Fast Green BLL (CFGBLL), G d, i.e. the value of moles of dye molecules degraded per joule of energy absorbed (sometimes given in units of the number of molecules decomposed per 100 eV of radiation energy absorbed) was measured in aerated, oxygen- and nitrogen-saturated aqueous solutions. The G d values were found to be 0.063, 0.0715 and 0.033 μmol/J or (0.61, 0.69 and 0.32/100 eV) respectively. The relatively low degradation yield indicates the absence of chain reactions and probably the poor efficiency and economics, in terms of the practical application of the radiation process. For applications in the radiation treatment of waste water, it is noted that in the presence of oxygen and at higher concentration of CFGBLL, the value of G d increases markedly, so that it may be practical to monitor the extent of sterilization of water. In addition the radiation processing of CFGBLL waste water may also become economically feasible. The specific bimolecular rate constant of the reaction of CFGBLL with the .OH was determined by studying the effect of ethanol concentration on G d using competition kinetics. This rate constant was found to be k = 2.32 × 10 10 and 1.65 × 10 10 L mol/s at 610 and 380 nm wavelengths, respectively. Suggestions are made for the possible use of CFGBLL aqueous solution as a chemical dosimeter in the range of absorbed dose from 0.1 to 5 kGy.