Impact of pH and PS Concentration on the Thermal Degradation of Brilliant Coomassie Blue G-250: An Experimental and Modeling Approach

The degradation of Brilliant Coomassie Blue G-250 (BCB) was investigated using the thermally activated persulfate (TAP) process in deionized water. A kinetic model incorporating both hydroxyl (●OH) and sulfate (SO4●–) radicals was developed to predict pseudo-first-order rate constants (kₒ) for the interaction of BCB with these radicals. Experimental results demonstrated efficient BCB degradation under TAP treatment. A parametric study examining the effects of initial conditions such as solution pH, persulfate concentration, initial BCB concentration, and temperature revealed that higher persulfate dosages, lower BCB concentrations, and alkaline pH enhanced degradation performance. Complete removal of BCB was achieved within 20 min under optimal conditions ([BCB]0 = 10 mg/L, [PS]0 = 2 mg/L, neutral pH). The kinetic model showed strong agreement with experimental data across a broad range of pH and persulfate concentrations. The rate constants for BCB reactions with ●OH and SO4●– were determined through simulation to be 4.731 × 109 M−1s−1 and 1.07 × 109 M−1s−1, respectively. The selectivity analysis results revealed that SO4●– radicals played a dominant role in the degradation process across the various initial persulfate concentration scenarios. The remaining degradation was attributed to the contribution of ●OH radicals. These findings are linked to the higher reactivity of BCB with SO4●– compared to ●OH. Overall, the results demonstrate that TAP process is an effective method for the removal of emerging contaminants such as BCB from water.