Remediation of alachlor and atrazine contaminated water with zero-valent iron nanoparticles

Abstract

Zero-valent iron nanoparticles (nZVI, diameter < 90 nm, specific surface area = 25 m² g⁻¹) have been used under anoxic conditions for the remediation of pesticides alachlor and atrazine in water. While alachlor (10, 20, 40 mg L⁻¹) was reduced by 92–96% within 72 h, no degradation of atrazine was observed. The alachlor degradation reaction was found to obey first-order kinetics very closely. The reaction rate (35.5 × 10⁻³–43.0 × 10⁻³ h⁻¹) increased with increasing alachlor concentration. The results are in conformity with other researchers who worked on these pesticides but mostly with micro ZVI and iron filings. This is for the first time that alachlor has been degraded under reductive environment using nZVI. The authors contend that nZVI may prove to be a simple method for on-site treatment of high concentration pesticide rinse water (100 mg L⁻¹) and for use in flooring materials in pesticide filling and storage stations.

Keywords:

• Zero-valent iron (ZVI)
• iron nanoparticle
• alachlor
• atrazine
• pesticide rinse water

Acknowledgments

Grants from United States Geological Survey and North Dakota Water Resources Research Institute (USGS/NDWRRI Grant ID: 2007ND149B) and North Dakota State University Development Foundation (Centennial Research Award, 2007) are thankfully acknowledged.