Zero-valent iron reduction of nitrate in the presence of ultraviolet light, organic matter and hydrogen peroxide

This paper describes the use of metallic iron (Fe0) powder for nitrate removal in a well-mixed batch reactor. Important variables explored include Fe^0 dosage (1–3 g/L), UV light intensity (64–128 W), and the presence of propanol (20 mg/L as DOC) and H2O2 (100–200 mg/L). Accumulation of ferrous ions released from the Fe^0 surface can be expressed by an S-curve, which involves lag growth phase, exponential phase, rate-declining phase, and saturation phase. The removal of nitrate increases with increasing Fe^0 dosage; however, the removal makes no difference as the Fe^0 dosage is greater than 2 g/L. UV irradiation retards the dissolution of ferrous ion and the removal of nitrate. The species of propanol, which has a functional group of – OH, plays a role of organic inhibitor for Fe^0 corrosion. The presence of H2O2 appears to inactivate all reactions as the Fe^0 of 10 (mu)m, the H2O2 was seen to decompose rapidly through Fenton reaction. Nevertheless, the rate of ferrous accumulation or nitrate removal is slow. A