Degradation of humic acids through heterogeneous catalytic ozonation with bone charcoal

摘要

Catalytic ozonation has recently been used as a new means of contaminant removal from water and wastewater. In this study, bone charcoal (BC), a new catalyst prepared under laboratory conditions, was used to catalyze the ozonation of humic substances (HS) in aqueous solutions. The catalytic effect of bone charcoal and the relevant parameters of this ozonation process (solution pH, temperature, scavenger effect, humic acids concentration and BC dosage) were investigated. In the catalytic ozonation experiments, the degradation kinetics was investigated. The reaction rate and the rate constant were determined. The results showed that using a BC catalyst in the ozonation of HS produced a 1.43- and 1.56-fold increase in reaction rates compared to the sole ozonation processes (SOP) under acidic and alkaline conditions, respectively. Furthermore, the applicability of heterogeneous catalytic ozonation with bone charcoal (HCOBC) to humic acid degradation was evaluated by performing comparisons with H₂O₂, O₃, O₃/H₂O₂ and O₃/H₂O₂/BC processes. With the use of the Arrhenius equation, the activation energy (E_a) was calculated to be 10 kJ mol−1. The results also showed that under the different temperatures, the reaction of the catalytic ozonation of HS was defined as diffusion controlled in accordance with the activation energy. These findings suggest that the HCOBC can be applied as an efficient and feasible method for the removal of HS from water.