Nanocasted synthesis of ordered mesoporous cerium iron mixed oxide and its excellent performances for As(v) and Cr(vi) removal from aqueous solutions

Abstract

A novel ordered mesoporous cerium iron mixed oxide (OMCI) with high specific surface area and uniform and well-interconnected mesopores was synthesized through the nanocasting strategy using mesoporous silica (KIT-6) as a hard template. The obtained OMCI was used as an adsorbent to remove As(V) or Cr(VI) anions from aqueous solutions, and exhibited excellent performances with the maximum adsorption capacities of ∼106.2 and ∼75.36 mg g⁻¹ for As(V) and Cr(VI), respectively. A mechanism study showed that both Fe and Ce compositions participated in the As(V) or Cr(VI) adsorption process, and complex interactions were involved, including electrostatic attraction and the replacement of hydroxyl groups to form anionic negatively charged inner-sphere surface complexes. The OMCI material could be easily regenerated and reused while maintaining high adsorption capacities for As(V) and Cr(VI). Owing to their integrated features including high specific surface area, uniform and well-interconnected mesopores and specific acid–base surface properties, the synthesized OMCI material is expected to have good potential for the decontamination of As(V) or Cr(VI) polluted waters.