Perchlorate Remediation in Aquatic Systems by Zero Valent Iron

Abstract

Perchlorate remediation by zero valent iron was studied in this paper. Acid treatment of iron filings significantly enhanced the reduction rate of perchlorate, and the reduction rate was correlated reasonably well by pseudofirst-order reaction kinetics. A linear correlation relating the reaction rate constant to the square of iron dosage was developed which predicted reasonably well the performance of flow through experiments. Flow-through column experiments were conducted to test a permeable reactive barrier at a laboratory scale. Effluent perchlorate concentration was below 4 μg L⁻¹for a 4.27-day retention time. The experimental results revealed that perchlorate was adsorbed on the iron surface before being reduced. In a simulated ground water study, background anions decreased perchlorate reduction due to competitive behavior on the iron surface. The mechanism of perchlorate reduction on iron filings surface was also discussed.