Fast and highly efficient removal of chromium (VI) using humus-supported nanoscale zero-valent iron: Influencing factors, kinetics and mechanism

The injection of nanoscale zero-valent iron (NZVI) particles for groundwater remediation has received much interest. However, aggregation of NZVI has limited its application in site remediation. To overcome this problem, the synthesis of humus-supported nanoscale zero-valent (H-NZVI) with liquid-phase reducing method was investigated. A series of experimental results demonstrated that H-NZVI was successfully used to remove the chromium in groundwater with higher efficiency because of its high durability, good mechanical strength and dispersion. The removal mechanism of Cr(VI) from groundwater might consist of concurrent physical adsorption and chemical reduction onto the H-NZVI surface. Supported NZVI in humus has succeeded in preventing aggregation and oxidation. Batch experiment results showed that the rate of removal of Cr(VI) was in accord with pseudo-first-order reaction kinetics with different pH, initial Cr(VI) concentration and H-NZVI dosages. It is demonstrated that H-NZVI would become a promising eco-friendly material for in situ heavy metal remediation. (C) 2016 Elsevier B.V. All rights reserved.