Nanoscale zero-valent iron (nZVI) products are highly applicable in groundwater, industrial water, and wastewater treatment due to the high reduction properties, the small size of particles in the range of nanometers, large surface area, and high reactivity on most toxic contaminants. The ultimate aim of this study is to evaluate the removal performance of 2,4-dichlorophenoxyacetic acid (2,4-D) by nanoscaled ZVI particles. Synthesized nanoscale iron particles were characterized by X-ray diffraction and scanning electron microscopy (SEM). According to SEM images of nZVI, the particle size was under 100 nm in diameter. The specific surface area was measured by the N-2/BET method and determined as 44.7 +/- 0.4 m(2)/g. The influences of nZVI dosage, initial pH and effects of different processes were examined by batch experiments. Results were compared with Fenton and photo-Fenton processes and they showed that under optimized conditions, degradation by nZVI is more effective than Fenton and photo-Fenton reactions and a promising candidate for 2,4-D remediation.