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Decomposition of gaseous NH 3 from ammonia (NH 3 )-containing wastewater was explored using Ni-loading Al 2 O 3 catalysts. The thermochemical decomposition of an NH 3 /steam mixture (wet-NH 3 ) with different steam contents at 873, 923, and 973 K using a fixed-bed reactor under ambient pressure. The present results indicated that the catalysts can be deactivated by the formation of NiAl 2 O 4 , which can be thermodynamically generated, and confirmed that the extent of deactivation was greatly affected by the partial pressure of the steam (P H 2 O ). The catalytic activities at 873 K decreased with increasing P H 2 O , whereas the activity was constant above P H 2 O of 25 kPa. However, the NH 3 conversion was almost independent of the NH 3 flow rate and temperature, and ∼30% of the NH 3 was decomposed at each temperature. This study indicated that, even in the presence of steam, this catalyst could decompose NH 3 from NH 4 + -containing water.

Toluene hydrogenation reaction for methylcyclohexane (MCH) synthesis via Pt-loaded Al2O3 and TiO2 (Pt/ Al2O3 and Pt/TiO2) catalysts were investigated in a fixed bed reactor at 398-473 K and ambient pressure. Partial pressures of toluene, hydrogen and MCH were 60 to 91, 9 to 23, and 9 to 17 kPa, respectively. Pt-loaded catalysts showed higher activities in the order of Pt/Al2O3 Pt/TiO2 (anatase-rutile mixture, AR) Pt/TiO2 (anatase, A) Pt/TiO2 (rutile, R) above 423 K, whereas Pt/TiO2 (anatase) showed remarkably higher activities at 393 K. To estimate the effects of support species, kinetic analysis using rate-based model was conducted. The correlation between adsorption behavior and catalytic activities was investigated using a Langmuir-Hinshelwood model. The kinetic constants for each catalyst were almost same. It was considered that only kinetic constants cannot explain the catalytic activities. Coverage of toluene and MCH were independent of the reaction rates, however the reaction rates increased as hydrogen coverage increased for all catalysts.

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