Decoloration of simulated wastewater containing dye reactive black K-BR by zero-valent iron was investigated. The results showed that decoloration efficiency increased with decreasing pH or initial dye concentration

and increased with increasing iron loading. The reaction followed first-order kinetics initially but deviated from first-order behavior with increasing time. Considering the decrease of active surface area of zero-valent iron with time

decoloration kinetics was expressed as ln(c/c0)= K［1-exp(-kdt)］/kd.It indicated that kd was independent of iron loading and pH

and decreased with increasing initialdye concentration. K was proportional to iron loading，and decreased with increasing pH or initial dye concentration.