Abstract：Nanoscale zero valent iron particles (nZVI) were synthesized using liquid phase reduction method. TEM analysis indicated that the size of nZVI was < 20 nm, and clustered in the medium. It displayed high reactivity to decompose γ-hexachlorocyclohexane (γ-HCH). More than 90% of γ-HCH was removed in 90 min with 0.5 g/L of nZVI in the solution. The degradation reaction followed a pseudo-first order kinetic. The reaction rate coefficient and removal efficiency were affected by many factors, such as the amount of nZVI, pH, the initial concentration of γ-HCH and coexisting ions. The reaction rate decreased with increasing initial pH. NO3- greatly inhibited the degradation reaction, but Ca2+, Mg2+ and SO42- had little effect on it. Degradation products such as tetrachlorocyclohexene (TeCCH) and chlorobenzene (CB), were identified by GC/MS. Based on this, the main reaction mechanism was suggested as dehydrochlorination and dichloroelmination.
