The Removal of Ammonia from Water by a Hydrophobic Catalyst

Owing to the worldwide emphasis on eutrophication problem and the toxic property of ammonia on the aquatic living, the discharge of ammonia-containing water to aquifers is intensely focused. The ammonia containing waste produced in industries is usually characterized by high concentration and high temperature and is not treatable by biological methods directly. In this study, a process has been developed to remove ammonia from water by stripping ammonia from the aqueous phase followed by the gas-phase oxidation of ammonia over a Pt/SDB hydrophobic catalyst. An equation of the form r = kPNH3mPO2n modeled the reaction, the reaction order in ammonia was 1.4 and in oxygen was 0.6, and the activation energy was 17400 cal/mol in a gas reaction system, whereas the reaction order of ammonia in a trickle-bed reactor was 0.8, and the activation energy was 10131 cal/mol. The difference was due to the presence of water in the trickle-bed reactor. Combining the equilibrium reactions of ammonia in water (KNH4+, KH2O), ...