Deep Insight into the Sb(Iii) and Sb(V) Removal Mechanism by Fe-Cu-Chitosan Material
Currently, alleviating antimony (Sb) contamination in aqueous solutions is crucial for restoring and recovering ecological and environmental health. Due to its toxicity, bioaccumulation and mobile characteristics, developing an efficient technique for antimony decontamination is imperative. Herein, we prepared an Fe-Cu-chitosan (FCC) composite by a one-step coprecipitation method, in which nanoscale Fe/Cu acts as the active sites and the whole structure is exhibited as porous microscale particles. An Fe/Cu proportion of 2/1 (FCC-2/1) was determined to be the optimum proportion for antimony adsorption, specifically 34.5 mg·g-1 for Sb(III) and 26.8 mg·g-1 for Sb(V) (initial concentration: 5.0 mg·L-1). Spectral characterization, batch experiments and density functional theory (DFT) simulations were applied to determine the adsorption mechanism, in which surface hydroxyls (-OH) were responsible for antimony complexion and Cu was a major contributor to adsorption enhancement. According to kinetic analysis, Cu provided an electrostatic attraction during the adsorption process, which facilitated the transportation of antimony molecules to the material interface. In the meantime, the FCC electronic structure was modified due to the optimization of the Fe-Cu interface coupling. Compared with the existing monodentate and bidentate surface complexes, the Fe-Cu bidentate complex had the largest adsorption energy for both Sb(III) (-4.03 eV) and Sb(V) (-7.56 eV). Based on the Mullikan net charge, the intrinsic Fe-O-Cu bond might favor interfacial electronic redistribution. When the antimony molecule contacted the adsorption interface, the electrons transferred swiftly as Fe/Cu 3d and O 2p orbital hybridization occurred, in which the energy of occupied bonding orbitals and anti-bonding orbitals shifted into lower energy levels, thus inducing a stabilizing effect. This work may offer a new perspective for binary oxide construction and its adsorption mechanism analysis
Year of publication: |
[2022]
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Authors: | Wang, Tianning ; Jiao, Yonghong ; He, Mengchang ; Ouyang, Wei ; Lin, Chunye ; Liu, Xitao ; Xie, Haijiao |
Publisher: |
[S.l.] : SSRN |
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