[Reductive dechlorination of 4-chlorophenol using nanosacle iron].

Nanoscale Fe0 was synthesized through a reductive method and the size of the particles is in the range of 1 - 100 nm, observed by ESEM image. The experimental results demonstrated that these metal particles can reduce 4-chlorophenol (4-CP) completely in 20 hours, when the initial concentration was 20 mg/L. Dechlorination by Fe0 is the main reaction pathway, and phenol is the main product. As the concentration of 4-CP increased from 20 mg/L to 50, 100, 150 mg/L, the relative dechlorination ratio decreased obviously. But the reduced amounts of 4-CP increased. Temperature can influence dechlorination rate and change the reductive pathway. Dechlorination is the main reaction at 30 degrees C while some oxidized compounds may be produced at 10 degrees C. The transfer of iron atom may be an important factor, limiting the dechlorination rate. Moreover, the stability and durability of nanoscale Fe0 was assessed through batch studies over extended periods of time. The results indicated that nanoscale Fe0 can resist the shock of 4-CP concentration during 379 hours.