a comparative kinetic study on electro-chemical decolorization of some dyes in mixtures: multivariate hard modelling technique

In this study, kinetic electro-oxidations of four dyes were simultaneously evaluated on ti/ znomulti-walled carbon nanotubes anode [1]. the mixture of dyes includes acid red 33 (ar33), reactive orange 7 (ro7), acid yellow 3 (ay3) and malachite green (mg) and the kinetic processes were monitored spectrophotometrically. a time-spectral data was recorded in the time range 0 to 80 min and wavelength range of 220-700nm. the spectra of the analytes were severely overlapped in this wavelength range, a fact which prevents achieving the rate constants of the analytes usingcommon univariate analysis. to overcome this problem, the time-spectral data was resolved byclassical least squares method under known pure spectral profiles of the dyes, in turn, the kineticprofiles of the components were analyzed by hard modelling approach [2, 3]. the estimated rateconstants of the dyes and their uncertainties were 0.0675((±0.0034), 0.0262 (±0.002), 0.0168(±8.94×10−4) and 0.0158 (±4.95×10−4) for mg, ar33, ay3 and ro7, respectively. indeed, theresults revealed that mg is strongly degradable and the trend of the rate constants is as follows indescending order: mg > ar33 > ay3 > ro7.