The kinetics of ammonia oxidation by ferrate(VI) was determined as a function of pH (7.5-11.0) and temperature (10-35 C). The rates decrease with increase in pH. The pH dependence is probably related to protonation of ferrate(VI) and ammonia. The theoretical curve through data gave the rate constants; k7(HFeO4- + NH4+) = 8.460.50x10-1 M-1; k9(FeO42- + NH4+) = 1.260.11x10-1 M-1s-1; k10(FeO42- + NH3) = 1.1910.10x10-1 M-1 s-1. The activation parameters, H() and S() were found to be 67.3 3.5 kJ/mol and 33.1 0.2 J/molK, respectively. When ferrate(VI) was used in excess relative to ammonia in the oxidation reaction 22% of ammonia removal was achieved. The usefulness of ferrate(VI) to remove ammonia from wastewater is discussed.
