An Experimental Study of Chemical Oxygen Demand Removal from the Coking Wastewater Using Three-Dimensional Electrode Reactor

In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of MnxCe1-xO2/γ-Al2O3 was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min−1, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation.

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Kinetics of para-nitrophenol and chemical oxygen demand removal from synthetic wastewater in an anaerobic migrating blanket reactor

Journal of Hazardous Materials ◽

10.1016/j.jhazmat.2008.04.039 ◽

2009 ◽

Vol 161 (2-3) ◽

pp. 787-799 ◽

Cited By ~ 29

Author(s):

Özlem Selçuk Kuşçu ◽

Delia Teresa Sponza

Keyword(s):

Chemical Oxygen Demand ◽

Oxygen Demand ◽

Synthetic Wastewater ◽

Chemical Oxygen Demand Removal ◽

Kinetics Of

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Monitoring of Anoxic/Oxic Process for Nitrogen and Chemical Oxygen Demand Removal Using Fuzzy Neural Networks

Water Environment Research ◽

10.2175/106143008x390807 ◽

2009 ◽

Vol 81 (7) ◽

pp. 654-663 ◽

Cited By ~ 7

Author(s):

Mingzhi Huang ◽

Jinquan Wan ◽

Yongwen Ma

Keyword(s):

Neural Networks ◽

Chemical Oxygen Demand ◽

Oxygen Demand ◽

Fuzzy Neural Networks ◽

Chemical Oxygen Demand Removal ◽

Fuzzy Neural

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An electrochemical mechanisms study on steel/IrO2–Sb2O3 electrodes for oxidation of phenol in water

Canadian Journal of Chemistry ◽

10.1139/cjc-2014-0304 ◽

2015 ◽

Vol 93 (5) ◽

pp. 536-541

Author(s):

Pavithra Bhakthi Jayathilaka ◽

Gayani Chathurika Pathiraja ◽

Athula Bandara ◽

Nalaka Deepal Subasinghe ◽

Nadeeshani Nanayakkara

Keyword(s):

Chemical Oxygen Demand ◽

Removal Efficiency ◽

Hydroxyl Radicals ◽

Oxygen Demand ◽

Oxidation Mechanism ◽

Constant Current ◽

Anode Surface ◽

Radical Scavenger ◽

Chemical Oxygen Demand Removal ◽

Constant Current Density

Phenol, a known water pollutant, was electrochemically oxidized on a steel/IrO2–Sb2O3 novel anode. Since the oxidation mechanisms vary based on the anode material, a mechanisms study of electrooxidation of phenol on it was conducted. The phenol oxidation was carried out at 20 mA/cm2 constant current density with a pH 11.00 Na2SO4 medium at room temperature. During 6 h of electrolysis, samples were tested for chemical oxygen demand removal efficiency of the anode. The steel/IrO2–Sb2O3anode showed 76.3% chemical oxygen demand removal efficiency. Both 4-nitroso-N,N-dimethylaniline and the HCO3–/CO32– radical scavenger tests confirmed the formation and presence of the hydroxyl radicals in the system. Therefore, it was concluded that the hydroxyl radicals that are generated on the anode surface are the main cause for the oxidation mechanism. Moreover, ICE, HPLC, and UV-vis absorbance and cyclic voltammetry results confirmed the presence of catechol and benzoquinone as intermediates and the reaction mechanism.

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