Role of Zeolite-Supported Nanoscale Zero-Valent Iron in Selenate Removal

Nanoscale zero-valent iron-supported zeolite Na-P1 (Z-NZVI) was synthesized and technologically promoted for selenate (Se6+) removal from water. NZVI, Z, and Z-NZVI were characterized using XRD, FTIR, high-resolution transmission electron microscopy with energy-dispersive X-ray spectroscopy (HR-TEM-EDS), and XANES techniques. Morphology and visualizing analysis using HR-TEM-EDS demonstrated that NZVI was uniformly distributed on the surfaces of Z in the Z-NZVI sample, which apparently reduced the aggregation of NZVI and would thereby increase the reduction activity. The Z-NZVI demonstrated higher efficiency for Se6+ removal since the high synergistic effect of Se6+ reduction and sorption by Z-NZVI. XANES analysis indicated that Z-NZVI could enhance Se6+ reduction into and selenium (Se-0), while the adsorption phenomenon emerged on the Z-NZVI surface. Z performed as a supporter of the insoluble products, improving the reduction activity of NZVI. The high capacity of Z-NZVI provides promising technology for the removal of selenium from aqueous solutions.