Nanoremediation of Lindane Contaminated Soils

The application of nanoscale zero-valent iron (nZVI) for remediation of soils contaminated by organic pollutants has drawn great attention, mainly owing to its relatively low cost and low toxicity. The present study investigated the degradation of lindane (γ-HCH) by two types of nZVIs, NANOFER 25S (N25S) and NANOFER STAR (NS). Three types of soils (field sand, kaolin, and glacial till) were spiked with 50 mg/kg lindane and were treated using different concentrations of N25S and NS. The highest lindane removal rate obtained was 99.99% using 10 g/L N25S in kaolin. Similarly, a near complete removal of lindane was achieved in the field sand using 4 g/L NS and 4 g/L N25S with removal rates of 99.9 and 99.7%, respectively. A considerable portion of the lindane may have possibly been lost through volatilization during the process of spiking, resulting in an unexpected decrease of the initial lindane concentration from 50 to 37, 38, and 28 mg/kg in field sand, kaolin, and glacial till samples, respectively. It is concluded that the degradation efficiency of lindane increased with increasing nZVI concentration and maximum degradation was achieved in kaolin by NS and N25S. The results show that the average degradation rate was higher with N25S than NS due to better contact and uniformity of the N25S suspension than the NS solution prepared from the NS powder.