Immobilizing Fe0 nanoparticles on covalent organic framework towards enhancement of Cr(VI) removal by adsorption and reduction synergistic effect

Nanoscale zero-valent iron (NZVI, Fe0) has been widely used for reduction of strong toxic Cr(VI) to low toxic Cr(III), however, given the easy aggregation of NZVI, developing new substrate support for NZVI is highly desirable. In this study, via a simple in-situ growth method, NZVI was immobilized on porous TpPa-1 covalent organic frameworks (COFs), making it an effective adsorbent for adsorption and reduction of Cr(VI) from aqueous solution. Meanwhile, to make the composite of NZVI and COFs a uniform system, dopamine (DOPA) was used as a connector to combine them. The COFs with porous crystal structure provides controlled anchors for Fe0 loading as well as the reaction sites. Results verify that the Fe0/[email protected] exhibited an excellent performance in Cr(VI) removal due to synergistic effect of the composite, with the maximum removal capacity up to 516 mg/g. Furthermore, it maintained high removal capacity under acidic, neutral and alkaline environments. Therefore, the Fe0/[email protected] is a promising material for Cr(VI) removal from wastewater in practical application.