Tuning the structural configuration and functional interactions on the surfaces of two-dimensional (2D) layered iron oxychloride (FeOCl) nanosheets are of essence to attain extraordinary physical properties. In this study, we prepare bulk FeOCl slices (B-FeOCl) by a short-time microwave annealing, which exhibit favorable Pb(II) adsorption performance to the counterparts for the first time even in the presence of high-level competing cations (Na+, K+, Ca2+, and Mg2+). Computational studies fundamentally elucidate Pb(II) interacts exceptionally with Cl atom on FeOCl, while by increasing the exposure of O atom on FeOCl would further boost its absorbability of Pb(II), unraveling that the dominance of (110) facet on FeOCl is more critical for Pb adsorption than the (010) facet. We thus exfoliate intentionally the B-FeOCl to obtain ultrathin FeOCl nanosheets (U-FeOCl) that possess unique Cl- and O-enriched surfaces. The resulting U-FeOCl unsurprisingly achieve outstanding adsorption capacity of 709 mg g-1 for Pb. Moreover, we show that U-FeOCl also enable rapid adsorption kinetics—the time of adsorption equilibrium is shortened 3 times. By extensively characterizing the FeOCl-Pb adsorption complexes, we find that the improved adsorption capacity of U-FeOCl for Pb(II) is related to the increased Pb-O interactions. In particular, the decline of Fe-Cl and Fe-O pairs in U-FeOCl encourage the embedding of the Pb atom, rendering the electron redistribution of Fe atoms and the increase in the valent state of Fe.

Boosting lead adsorption on ultrathin iron oxychloride (FeOCl) nanosheets

2019 Spring National Meeting

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