High capacity adsorption of antimony in biomass-based composite and its consequential utilization as battery anode

•An antimony adsorbent with record capacity from the balanced view of Sb(III) and Sb(V).•The mechanism of Sb adsorption is described as: initiation with Fe3O4, propagation along chitosan, and termination with EDTA.•Adsorption of Sb affords highly dispersed Sb@C as Li+/Na+ battery anode.•The recycle of waste adsorbent and resource utilization of pollutant in water. Antimony is more than an emerging pollutant in water but a scare resource. In this study, we report an adsorbent with the record capacity so far from the balanced view of Sb(III) and Sb(V). The composite adsorbent was fabricated by encapsulating hollow Fe3O4 nanosphere with the EDTA grafted chitosan, and it has superhigh adsorption capacity of for 657.1 mg/g for Sb(III) and 467.3 mg/g for Sb(V), respectively. The mechanism study reveals that the adsorption of Sb initializes from the Fe3O4, propagates along the chitosan with hydrogen bond, and terminates at the inner sphere complex with the EDTA moiety in the adsorbent. In view of the ultra-high adsorption capacity of the adsorbent, the recovered adsorbent that contains abundant (>36.4%) highly dispersed antimony nanoparticles (600-FCSE-Sb) is applied to Li-ion battery anode after reduction. This article provides a new idea for connecting water treatment and electric energy storage. Fe3O4-CS/EDTA has a record high capacity to absorb antimony and afford highly dispersed Sb@C as Li+/Na+ battery anode. [Display omitted]