Treatment of ammonia by catalytic wet oxidation process over platinum-rhodium bimetallic catalyst in a trickle-bed reactor: effect of pH.
This work adopted aqueous solutions of ammonia for use in catalytic liquid-phase reduction in a trickle-bed reactor with a platinum-rhodium bimetallic catalyst, prepared by the co-precipitation of chloroplatinic acid (H2PtCl6) and rhodium nitrate [Rh(NO3)3]. The experimental results demonstrated that a minimal amount of ammonia was removed from the solution by wet oxidation in the absence of any catalyst, while approximately 97.0% of the ammonia was removed by wet oxidation over the platinum-rhodium bimetallic catalyst at 230 degrees C with an oxygen partial pressure of 2.0 MPa. The oxidation of ammonia has been studied as a function of pH, and the main reaction products were determined. A synergistic effect is manifest in the platinum-rhodium bimetallic structure, in which the material has the greatest capacity to reduce ammonia. The reaction pathway linked the oxidizing ammonia to nitric oxide, nitrogen, and water.
Hung
Chang-Mao
CM
Department of Vehicle Engineering, Yung-Ta Institute of Technology & Commerce, Taiwan, ROC. hungcm1031@gmail.com
Lin
Wei-Bang
WB
Ho
Ching-Lin
CL
Shen
Yun-Hwei
YH
Hsia
Shao-Yi
SY
D000641:Ammonia / Q000302:isolation & purification*; D002384:Catalysis; D006863:Hydrogen-Ion Concentration; D010084:Oxidation-Reduction; D010984:Platinum / Q000737:chemistry*; D012238:Rhodium / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet; D014865:Waste Disposal, Fluid / Q000379:methods*; D014961:X-Ray Diffraction
D010984:Platinum; D000641:Ammonia; D012238:Rhodium