Degradation of Chlorinated Organic Compounds by Mixed Particles of Iron/Iron Sulfide or Iron/Iron Disulfide

Abstract

Kinetic study was carried out in order to clear a mixing effect of Fe–FeS or Fe–FeS₂ particles on increase in degradation rate of chlorinated organic compounds. Trichloroethylene (TCE) contained solution was used for dechlorination in 30 mL of vial bottle and mixed by rotary device. Estimating that TCE concentration in solution was proportional to TCE gas concentration in head space of vial bottle, gas was obtained from the head space with syringe and measured by GC-FID. TCE degradation occurred on Fe, FeS, Fe–FeS and Fe–FeS₂ particles except FeS₂. TCE degradation of mixed particles of Fe–FeS or Fe–FeS₂ was explained by anode (Fe)–cathode (FeS or FeS₂) reaction. TCE degradation rates of Fe–FeS and Fe–FeS₂ caused by anode/cathode reaction were 2.81 × 10⁻⁶ and 1.37 × 10⁻⁵ (m/h), respectively, which were larger than those of pure Fe and FeS. There was no difference in TCE degradation rate of mixed particles of Fe–FeS or Fe–FeS₂ between aerobic and anaerobic solutions. TCE degradation rate of mixed particles of Fe–FeS or Fe–FeS₂ increased in decrease in size of FeS or FeS₂. TCE degradation rate of mixed particles of Fe–FeS or Fe–FeS₂ increased with increase in decomposition temperature.