The rates of thiourea oxidation with Fe(VI) were determined as a function of pH (8.8-11.5) and temperature (10-35℃). The rate law for the oxidation of thiourea was found to be -dFe(VI)/dt = ko{H{sup}+/H{sup}++K{sub}9)}Fe(VI)thioureawhere k{sub}0 = 5.9×10{sup}4 M{sup}-1 s{sup}-1, pK{sub}9 = 7.8. The activation energy, △E{sup}≠, obtained was 32.2± 1.8 kJ mol{sup}-1. The rate constant for the reaction of Fe(VI) with the thiourea radical was determined by using a premix pulseradiolysis technique and was found to be 8.5×10{sup}8 M{sup}-1s{sup}-1 at pH = 9.0. The stoichiometric ratio of Fe(VI) and thiourea was found to be 1:0.38±0.02 at pH = 9.0. Sulfate and urea were identified as the products of the reaction. Tests wereconducted on the oxidative destruction of thiourea by Fe(VI) in synthetic boiler chemical cleaning wastes (BCCW) and are discussed.
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