Article ID Journal Published Year Pages File Type
5157377 Carbohydrate Polymers 2017 32 Pages PDF
Abstract
Using Fe(III) salts and chitosan, nano iron oxide impregnated in chitosan bead (NIOC) was successfully synthesized for aqueous Cr(VI) detoxification via sol-gel technique without any additional crosslinking agent. NIOC characterization demonstrated that the iron in NIOC mainly existed as nano akaganeite (β-FeOOH) and complex with chitosan. Intraparticle diffusion was the major rate-limiting step. The maximal adsorption capacity was 69.8 mg/g (pH 5.0, 20 °C). Normal concentration of coexisting anions (SO42−, CO32−, SiO32−) showed insignificant competition, whereas PO43− suppressed the Cr(VI) sorption. Cr(VI)-loaded NIOC could be effectively regenerated by alkaline solutions. Column adsorption runs using granular NIOC could effectively treat about 1600 bed volumes of Cr(VI) solution (from 3.7 mg Cr/L in influent to <0.5 mg Cr/L in effluent). The Cr(VI) removal mechanisms involved the direct sorption of Cr(VI) (electrostatic attraction and ligand exchange), reduction of Cr(VI) into Cr(III) and re-sorption of Cr(III) via chelation on NIOC surface.
Related Topics
Physical Sciences and Engineering Chemistry Organic Chemistry
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