文摘
Nanosized zerovalent iron (nFe0) loaded with a secondary metal such as Ni or Cu on its surface was demonstrated to effectively activate periodate (IO4鈥?/sup>) and degrade selected organic compounds at neutral pH. The degradation was accompanied by a stoichiometric conversion of IO4鈥?/sup> to iodate (IO3鈥?/sup>). nFe0 without bimetallic loading led to similar IO4鈥?/sup> reduction but no organic degradation, suggesting the production of reactive iodine intermediate only when IO4鈥?/sup> is activated by bimetallic nFe0 (e.g., nFe0鈥揘i and nFe0鈥揅u). The organic degradation kinetics in the nFe0鈥揘i(or Cu)/IO4鈥?/sup> system was substrate dependent: 4-chlorophenol, phenol, and bisphenol A were effectively degraded, whereas little or no degradation was observed with benzoic acid, carbamazepine, and 2,4,6-trichlorophenol. The substrate specificity, further confirmed by little kinetic inhibition with background organic matter, implies the selective nature of oxidant in the nFe0鈥揘i(or Cu)/IO4鈥?/sup> system. The comparison with the photoactivated IO4鈥?/sup> system, in which iodyl radical (IO3鈥?/sup>) is a predominant oxidant in the presence of methanol, suggests IO3鈥?/sup> also as primary oxidant in the nFe0鈥揘i(or Cu)/IO4鈥?/sup> system.
