Dual-Core Fe₂O₃@Carbon Structure Derived from Hydrothermal Carbonization of Chitosan as a Highly Efficient Material for Selective Adsorption

Abstract

A dual-core Fe 2 O 3 @carbon structure was prepared by a hydrothermal treatment of iron salt and chitosan (CS) solution. The structure exhibits microsphere-like (∼850 nm in size) morphology with dual cores at two ends. The existence of CS plays an important role in the formation of the dual-core−shell structure. The unique structure was investigated to be a CS adsorption, and subsequent carbonization induced a selective etching process. Further, the special structure was proven to be a highly efficient material for selective adsorption. The dual-core structure facilitates the exposure of the Fe 2 O 3 surface, and the carbonaceous shell gives plenty of functional groups for selective adsorption. More importantly, the selectivity was highly dependent on pH values. It was found that the adsorbent showed higher adsorption selectivity toward Cr(VI) at lower pH values, while the selectivity transferred toward Cu(II) at higher pH values by adsorption of Cu(II) and Cr(VI) in single-component solutions. In binary-component solution, the dual-core Fe 2 O 3 @C structure revealed adsorption selectivity for Cr(VI), with the highest separator factor [α Cu(II) Cr(VI) ] = 1162, due to the strong electrostatic adsorption-coupled reduction interaction induced by the special structure of the adsorbent. This work not only gives deep insights into the understanding of the formation of the dual-core structure but also supplies a novel adsorbent with selective adsorption properties for water treatment.

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Magnetic graphene oxide grafted with different hydrophobic chain lengths low‐generation polyamidoamine dendrimers for adsorption of Pb(II) and Hg(II) in aqueous solution

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Green and Size-Specific Synthesis of Stable Fe–Cu Oxides as Earth-Abundant Adsorbents for Malachite Green Removal

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