Synthesis of the mesoporous carbon-nano-zero-valent iron composite and activation of sulfite for removal of organic pollutants

The metal-catalyzed sulfite system has attracted attention in recent years as an advanced oxidation process for the oxidative treatment of pollutants. In this study, a synthesized mesoporous carbon-nano-zero-valent iron composite material, denoted as Fe-C, has been used for the removal of organic pollutants in a sulfite catalyzing system. TEM, XRD, XPS, TG, and BET surface area have been applied to characterize the material, and confirmed the formation of Fe-0 in the Fe-C composite. The results revealed > 90% removal of reactive red dye X-3B within 30 min with the Fe-C/sulfite system. A mechanistic study revealed contributions from both adsorptive removal (ca. 30%) and oxidative removal (ca. 70%) for X-3B at initial pH 7. Both HO center dot and SO4 center dot- were found to be generated in the Fe-C/sulfite system. The factors influencing X-3B removal have been investigated, namely pH, composite dosage, sulfite dosage, and initial concentration of X-3B. In assessing the reusability of the complex in X-3B removal, an approximate 30% decrease in removal efficiency in the second use was seen. Study of the applicability of the Fe-C/sulfite system showed good removal efficiencies for a variety of organic contaminants.