Research on dye wastewater decoloration by pulse discharge plasma combined with charcoal derived from spent tea leaves
2016
Wang, Tiecheng | Qu, Guangzhou | Pei, Shuzhao | Liang, Dongli | Hu, Shibin
Pulsed discharge plasma (PDP) combined with charcoal (PDP–charcoal) was employed to treat dye wastewater, with methyl orange (MO) as the model pollutant. The charcoal was prepared using spent tea leaves and was characterized by scanning electron microscopy, Fourier-transform infrared spectroscopy, and Boehm titration to investigate the adsorption and catalytic characteristics before and after adsorption and PDP treatment. The prepared charcoal exhibited a high MO adsorption capacity, and the adsorption process followed the pseudo-second-order kinetic model and the Freundlich model. The MO decoloration efficiency reached 69.8 % within 7.5 min of treatment in the PDP–charcoal system, whereas values of 29.2 and 25.9 % were achieved in individual PDP and charcoal systems, respectively. The addition of n-butanol and H₂PO₄ ⁻ presented inhibitive effects on MO decoloration in the PDP system. However, these effects were much weaker in the PDP–charcoal system. In addition, the effects of charcoal on O₃ and H₂O₂ formation were evaluated, and the results showed that both the O₃ and H₂O₂ concentrations decreased in the presence of charcoal. The MO decomposition intermediates were analyzed using UV–Vis spectrometry and GC-MS. 1,4-Benzoquinone, 4-nitrophenol, 4-hydroxyaniline, and N,N′-dimethylaniline were detected. A possible pathway for MO decomposition in this system was proposed.
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