Authors: Deuk Ki Lee Jeong Shik Cho Taejong Yu Yong Su Lee Jae Wan Choe Sang Soo Lee
Publish Date: 2016/07/30
Volume: 33, Issue: 11, Pages: 3109-3114
Abstract
A kinetic model for the catalytic wet air oxidation of aqueous ammonia over Ru/TiO2 catalyst was developed considering the consecutive reaction steps as follows i formation of active oxygen sites O by the dissociative adsorption of aqueous O2 on the catalyst ii oxidation of aqueous NH3 by the reaction with three O sites to produce HNO2 iii aqueous phase dissociation of HNO2 into H+ and NO 2 − iv formation of NH 4 + by the association of NH3 with the HNO2dissociated H+ v formation of N2 by the aqueous phase reaction between NO 2 − and NH 4 + vi formation of NO3 by the reaction of NO 2 − with an O site For each reaction step a rate equation was derived and its kinetic parameters were optimized by experimental data fitting Activation energies for the reactions ii v and vi were 1231 767 and 545 kJ/mol respectively suggesting that the oxidation reaction of aqueous NH3 to HNO2 was a ratedetermining step From the simulation using the kinetic parameters determined the initial pH adjustment of the ammonia solution proved to be critical for determining the oxidation product selectivity between desirable N2 and undesirable NO 3 − as well as the degree of oxidation conversion of ammonia
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