Synthesis of MCM-41 stabilized NZVI and its use in removal of Cr(VI) from aqueous solution

In this study, MCM-41 stabilized nano zero-valent iron (M-NZVI) is synthesized using the rheological phase reaction method. Characterization with transmission electron microscopy validates the hypothesis that the introduction of MCM-41 leads to a decrease in aggregation of iron nanoparticles. X-ray diffraction confirms the existence of Fe and the strong antioxidant activity of Fe nanoparticles. Batch Cr(VI) reduction experiments exhibit that solution pH, M-NZVI dosage, and reaction time have significant effects on Cr(VI) removal. A high removal efficiency of Cr(VI) (84.5%) is obtained within 60 min for 100 mg/L of Cr(VI) solution at an initial pH of 6.0 and M-NZVI dosage of 0.5 g/L at 35 °C. The Cr(VI) removal rates follow modified pseudo-first-order kinetic equations. The observed removal rate constant was 0.0168/min for the M-NZVI dosage of 1.0 g/L. Our study suggests that the introduction of an innocuous stabilizer such as MCM-41 can significantly improve the performance of Fe nanoparticles for environmental remediation applications.