Effect of hexadecyl trimethyl ammonium bromide on sonocatalytic degradation of Orange II by using bagasse biochar

The heterogeneous micro-interface plays a crucial role in facilitating mass transfer and catalytic conversion. This study aimed to investigate the influence of the surfactant cetyltrimethyl ammonium bromide (CTAB) on micro-interface properties during sonocatalytic degradation of Orange II using bagasse biochar. Our findings indicate that increasing the concentration of CTAB or the dosage of bagasse biochar significantly enhances sonocatalytic degradation efficiency. However, an increase in solution pH was observed to have a detrimental effect on degradation efficiency, while higher ultrasonic power proved beneficial for Orange II degradation when CTAB was present. Moreover, the pseudo-first-order rate constant (K-app) for the sonocatalytic process was 1.3 times that of the sum of combined K-app values obtained with ultrasonication and biochar adsorption individually, indicating a substantial synergistic effect when bagasse biochar and ultrasonication are combined in the presence of CTAB. The influence of inorganic anions on sonocatalytic degradation of Orange II, in the presence of CTAB, was relatively weak. Quenching tests using iso-propanol and KBr indicated that free radical chain reactions predominantly occurred at the micro-interface, with limited involvement in bulk solutions during the sonocatalytic degradation process. Overall, our results indicate that OH radicals remained the dominant contributors to the overall reaction.