Remediation of Anthracene-Contaminated Soil by ClO2 in the Presence of Magnetic Fe3O4-CuO@Montmorillonite as Catalyst

Fe 3 O 4 -CuO@montmorillonite was prepared using coprecipitation method, and its structure was determined by XRD, IR, and transmission electron micrograph (TEM). Montmorillonite in Fe 3 O 4 -CuO@montmorillonite nanocomposite allowed the silicate layer of montmorillonite to behave as a barrier, which prevented the agglomeration and natural crystallization of Fe 3 O 4 and CuO. Furthermore, the chlorine dioxide (ClO 2 ) oxidative degradation of anthracene-contaminated soil was studied in detail using Fe 3 O 4 -CuO@montmorillonite as a magnetic heterogeneous catalyst. The operating parameters such as ClO 2 concentration, catalyst dosage, reaction time, and pH were evaluated. Compared with the conventional ClO 2 oxidation process without the catalyst, the ClO 2 catalytic oxidation system could significantly enhance the degradation efficiency. Under the optimal condition (anthracene concentration 89.8 mg/kg, water soil mass ratio 3:1, initial pH 7, ClO 2 concentration 1 mol/kg, catalyst dosage 1 g/kg, reaction time 30 min, and reaction temperature 25 °C), anthracene degradation efficiency achieved 96.2 %. The catalyst could be easily reused by magnetic separation and used at least 8 cycles without obvious loss of activity. The kinetic studies revealed that the ClO 2 catalytic oxidation degradation of anthracene-contaminated soil with Fe 3 O 4 -CuO@montmorillonite as catalyst followed pseudo-first-order kinetics with respect to ClO 2 concentration. Thus, this study showed potential application of ClO 2 catalytic oxidation process in remediation of organic pollutant-contaminated soil.