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Treatment of coking wastewater using a needle coke electro-Fenton cathode: optimizing of COD, NH4+-N, and TOC removal and characterization of pollutants
- Source :
- Water Science and Technology, Vol 88, Iss 1, Pp 106-122 (2023)
- Publication Year :
- 2023
- Publisher :
- IWA Publishing, 2023.
-
Abstract
- Coking wastewater is a typical organic refractory wastewater characterized by high chemical oxygen demand (COD), NH4+-N, and total organic carbon (TOC). Herein, coking wastewater was treated using a heterogeneous electro-Fenton (EF) system comprising a novel iron-loaded needle coke composite cathode (Fe-NCCC) and a dimensionally stable anode. The response surface methodology was used to optimize the reaction conditions. The predicted and actual COD removal rates were 92.13 and 89.96% under optimum conditions of an applied voltage of 4.92 V, an electrode spacing of 2.29 cm, and an initial pH of 3.01. The optimized removal rate of NH4+-N and TOC was 84.12 and 73.44%, respectively. The color of coking wastewater decreased from 250-fold to colorless, and the BOD5/COD increased from 0.126 to 0.34. Gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy show that macromolecular heterocyclic organic compounds decomposed into straight-chain small molecules and even completely mineralized. The energy consumption of the EF process was 23.5 RMB Yuan per cubic meter of coking wastewater. The EF system comprising the Fe-NCCC can effectively remove pollutants from coking wastewater, has low electricity consumption, and can simultaneously reduce various pollution indicators with potential applications in the treatment of high-concentration and difficult-to-degrade organic wastewater. HIGHLIGHTS A novel needle coke composite cathode was fabricated to treat coking wastewater.; The maximum COD removal was ∼90% using an electro-Fenton process.; The COD, -N, and TOC removal rates were optimized using the Box–Behnken design.; Macromolecular organic matter in coking wastewater was degraded after treatment.;
Details
- Language :
- English
- ISSN :
- 02731223 and 19969732
- Volume :
- 88
- Issue :
- 1
- Database :
- Directory of Open Access Journals
- Journal :
- Water Science and Technology
- Publication Type :
- Academic Journal
- Accession number :
- edsdoj.52081775768647a8b192fed3fdf87e7a
- Document Type :
- article
- Full Text :
- https://doi.org/10.2166/wst.2023.172