Shengtao Jiang

Degradation Effect and Mechanism of Dinitrotoluene Wastewater by Magnetic Nano-Fe3O4/H2O2 Fenton-like

ABSTRACT The characteristics and influencing factors for dinitrotoluene degradation by nano-Fe3O4-H2O2 were studied, and the nano-scale Fe3O4 catalyst was prepared by the coprecipitation method, with dinitrotoluene wastewater as the degradation object. The results showed that the catalytic reaction system within the pH value range of 1 to 9 could effectively degrade dinitrotoluene, and the optimal pH value was 3; with the increase of catalyst dosage, the degradation efficiency and the catalytic reaction rate of dinitrotoluene grew as well. The optimal catalyst dosage was 1.0 g/L when the H2O2 dosage was within the range of 0 to 0.8 mL/L; the degradation efficiency and reaction rate grew with the increase of H2O2 dosage. With further increase of H2O2 dosage, degradation efficiency and reaction rate decreased; under the best conditions with the H2O2 dosage of 0.8 mL/L, the catalyst concentration of 1 g/L and the pH value of 3 at room temperature (25 °C), the degradation rate of the 100-mg/L dinitrotoluene in 120 min reached 97.6%. Through the use of the probe compounds n-butyl alcohol and benzoquinone, it was proved that the oxidation activity species in the nano-Fe3O4-H2O2 catalytic system were mainly hydroxyl radical (•OH) and superoxide radicals (HO2 •), based on which, the reaction mechanism was hypothesized.

Effectiveness and Mechanisms of Fenton-like Si-FeOOH/H2O2 in 2,4-Dichlorophenol Wastewater Treatment

This research measured the effectiveness of Si-FeOOH as a type of heterogeneous Fenton-like catalyst made from alkaline precipitation methods, in catalyzing the degradation of 2,4-dichlorophenol (2,4-DCP) wastewater. Factors including catalyst dosage, pH, and hydrogen peroxide dosage were investigated, showing: with an initial concentration of 2,4-dichlorophenol at 100 mg/L, a dosage of catalyst at 0.1 g/L, a dosage of H2O2 at 1.5 ml/L, pH at 5 and indoors temperature at 25 ± 1 °C, the degradation rate of 2,4-dichlorophenol, CODCr and TOC has reached 94.21%, 83.67%, and 76.11%, separately. Comparisons were made with FeOOH used as catalyst, showing that Fenton-like Si-FeOOH is a better catalyst than FeOOH.