Nanoscale zero-valent iron (Fe(0)) was synthesized for nitrate denitrification. The reduction efficiency of nitrate decreased quickly with increasing initial pH value, increased considerably with the increasing dosage of nanoscale Fe(0), and did not vary much with initial nitrate concentrations changing from 20 to 50 mg l(-1) when the excessive amount of nanoscale Fe(0) was utilized. With reductive denitrification of nitrate by nanoscale Fe(0), the removal rate of nitrate reached 96.4% in 30 min with nanoscale Fe(0) dosage of 1.0 gl(-1) and pH(in) 6.7, and more than 85% of the nitrate was transformed into ammonia. Kinetics analysis in batch studies demonstrates that the denitrification of nitrate by nanoscale Fe(0) involves reaction on the metal surface, which fits well the pseudo-first order reaction with respect to nitrate concentration. The observed reaction rate constant of reductive denitrification of nitrate was determined to be 0.086 min(-1) with a nanoscale Fe(0) dosage of 1.0 gl(-1) and pH(in) 6.7. Fast and highly effective denitrification can be achieved by nanoscale Fe(0) compared with commercial Fe(0) powder, this is due to the extremely high surface area and high reactivity for nanoscale Fe(0), which can enhance the denitrification efficiencies remarkably. (C) 2010 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.