Catalytic Wet Air Oxidation of Coke-Plant Wastewater on Ruthenium-Based Eggshell Catalysts in a Bubbling Bed Reactor
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Catalytic wet air of coke-plant wastewater was studied in a bubbling bed reactor. Two types of supported Ru-based catalysts, eggshell and uniform catalysts, were employed. Compared with the results in the wet air oxidation of coke-plant wastewater, supported Ru uniform catalysts showed high activity for chemical oxygen demand (COD) and ammonia/ammonium compounds (NH3-N) removal at temperature of 250 °C and pressure of 4.8 MPa, and it has been demonstrated that the catalytic activity of uniform catalyst depended strongly on the distribution of active sites of Ru on catalyst. Compared to the corresponding uniform catalysts with the same Ru loading (0.25wt.% and 0.1wt.%, respectively), the eggshell catalysts showed higher activities for CODcr removal and much higher activities for NH3-N degradation. The high activity of eggshell catalyst for treatment of coke-plant wastewater can be attributed to the higher density of active Ru sites in the shell layer than that of the corresponding uniform catalyst with the same Ru loading. It has been also evidenced that the active Ru sites in the internal core of uniform catalyst have very little or no contribution to CODcr and NH3-N removal in the total oxidation of coke-plant wastewater.
KeywordsCatalytic wet air oxidation Ru catalysts Bubbling bed reactor Eggshell catalyst Coke-plant wastewater
This work was supported by the National High Technology Project (program number 2002AA601260).
- Hockenbury MR, Grady CPL (1977) Inhibition of nitrification-effects of selected organic compounds. J Water Pollut Control Fed 49: 768–777Google Scholar
- Melcer H, Nutt S, Marvan I, Sutton P (1984) Combined treatment of coke plant wastewater and blast furnace blowdown water in a coupled biological fluidized system. J Water Pollut Control Fed 56: 192–198Google Scholar
- Wen YB, Zhang M, Qian Y (1991) Biological treatment of coke-plant wastewater for COD and NH3–N removal. Water Sci Technol 23: 1883–1892Google Scholar