Tunable synthesis of SiO(2)-encapsulated zero-valent iron nanoparticles for degradation of organic dyes

A series of nanocomposites consisting of zero-valent iron nanoparticles (ZVI NPs) encapsulated in SiO(2) microspheres were successfully synthesized through a successive two-step method, i.e., the wet chemical reduction by borohydride followed by a modified Stöber method. The as-synthesized nanocomposites were characterized using X-ray diffraction, field emission scanning electron microscopy, vibrating sample magnetometer, and inductively coupled plasma-atomic emission spectrometer. The catalytic performance of SiO(2)-encapsulated ZVI nanocomposites for the degradation of organic dyes was investigated using methylene blue (MB) as the model dye in the presence of H(2)O(2). The results showed that the degradation efficiency and apparent rate constant of the degradation reaction were significantly enhanced with increased ZVI NPs encapsulated in SiO(2) microspheres, whereas the dosage of H(2)O(2) remarkably promoted degradation rate without affecting degradation efficiency. The content-dependent magnetic property ensured the excellent magnetic separation of degradation products under an external magnet. This strategy for the synthesis of SiO(2)-encapsulated ZVI NPs nanocomposites was low cost and easy to scale-up for industrial production, thereby enabling promising applications in environmental remediation.