1Discipline of Chemical Engineering, School of Engineering, Monash University Sunway Campus, Jalan Lagoon Selatan, 46150 Bandar Sunway, Selangor, MALAYSIA
2School of Chemical Engineering, Engineering Campus, University Sains Malaysia, 14300, Nibong Tebal, Penang, MALAYSIA
3School of Chemical Engineering, Engineering Campus, University Sains Malaysia, 14300, Nibong Tebal, Penang, MALAYSIA
The NO removal over oxide sorbents (K2O/Al2O3 , CaO/Al2O3 and BaO/Al2O3) at a loading of up to 25 wt.% was investigated using a synthetic diesel exhaust gas containing 1,000 ppm NO, 1000 ppm iso-butane (i-C4H10), 8% O2 and N2 balance. The reactor was operated at 250 oC to 450 oC for the activity study. NO was effectively stored (removal efficiencies between 30-60 %) as nitrate under experimental conditions after surface oxidation to NO2; and the maximum removal efficiency decreased in the order of K2O/Al2O3 (55.4 %) > BaO/Al2O3 (39.0 %) > CaO/Al2O3 (37.0 %). K2O/Al2O3 had higher mobility; but loadings higher than 15 wt.% were detrimental to the morphological properties. Despite higher basicity, CaO/Al2O3 showed lower removal efficiency of NO compared to BaO(10)/Al2O3 due to low catalytic NO2 formation activity. Unlike K2O(10)/Al2O3, BaO(10)/Al2O3 showed increasing NO removal between 350 oC and 450 oC. K2O(5)BaO(5)/Al2O3 resulted in better surface area and volume leading to about 65 % of NO removal. This was attributed to synergic effects between physicochemical, catalytic and NO removal properties of the components.The high performance of K2O(5)BaO(5)/Al2O3 wassuccessfully elucidated based on the characteristics of the sorbent.
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