Optimization of laccase catalyzed degradation of reactive textile dyes in supercritical carbon dioxide medium by response surface methodology

Abstract

In this work, the laccase catalyzed degradation of reactive textile dyes was studied in supercritical carbon dioxide media. A two level Box–Behnken factorial design with two factors and response surface methodology (RSM) were performed to investigate and optimize the effects of pressure and temperature on reactive red 239 (RR239), reactive yellow 15 (RY15) and reactive black 5 (RB5) dye degradations by commercial laccase in supercritical carbon dioxide media. Mathematical models were developed for each dye showing the effect of each factor and their interactions on color removal. Pressure and the interaction between temperature and pressure were the main factors affecting the decolorization. The optimum conditions for RB5 and RY15 were found to be high pressure values (>120 bar), whilst the temperature presented a minor effect on their degradation at these pressures. For RR239, both variables influenced the decolorization and the optimum conditions appear to be at low values of pressure and high values of temperature.