Background:
Coal gangue was used as a catalyst in heterogeneous Fenton process
for the degradation of azo dye and phenol. The influencing factors, such as solution pH
gangue concentration and hydrogen peroxide dosage were investigated, and the reaction
mechanism between coal gangue and hydrogen peroxide was also discussed.
Methods:
Experimental results showed that coal gangue has the ability to activate hydrogen
peroxide to degrade environmental pollutants in aqueous solution. Under optimal conditions,
after 60 minutes of treatment, more than 90.57% of reactive red dye was removed, and the
removal efficiency of Chemical Oxygen Demand (COD) up to 72.83%.
Results:
Both hydroxyl radical and superoxide radical anion participated in the degradation
of organic pollutant but hydroxyl radical predominated. Stability tests for coal gangue were
also carried out via the continuous degradation experiment and ion leakage analysis. After
five times continuous degradation, dye removal rate decreased slightly and the leached Fe
was still at very low level (2.24-3.02 mg L-1). The results of Scanning Electron Microscope
(SEM), energy dispersive X-Ray Spectrometer (EDS) and X-Ray Powder Diffraction (XRD)
indicated that coal gangue catalyst is stable after five times continuous reuse.
Conclusion:
The progress in this research suggested that coal gangue is a potential nature
catalyst for the efficient degradation of organic pollutant in water and wastewater via the
Fenton reaction.
Comparison of hydrogen atom and hydroxyl radical reactions with simple aromatic molecules in aqueous solution