A highly efficient adsorbent constructed by the in situ assembly of Zeolitic imidazole framework-67 on 3D aramid nanofiber aerogel scaffold

Abstract

• ZIF-67 was in situ assembled onto ANF aerogel to get 3D monolith adsorbent. • ANF/ZIF-67 aerogel showed stable and competitive structural features. • ANF/ZIF-67 aerogel demonstrated high adsorption capacity for Cu 2+ and Cr 6+ . • ANF/ZIF-67 aerogel displayed excellent adsorption capacity for CV and MO. • The adsorption capacity maintained up to 80% after five times of usage. The fabrication of a high-efficiency adsorbent, as a promising candidate for removing metal ions and organic dyes from aqueous solution, is a research hotspot but remains challenging. Aramid nanofibers (ANFs) are emerging building blocks that have realized multifunctional applications in various fields because of their intrinsic mechanical and chemical stability. In this research, three-dimensional (3D) ANF aerogel was assembled and applied in for in situ assembly of zeolitic imidazole framework-67 (ZIF-67). The aim, was to fully exploit the structural advantages of this composite’s ultra-low bulk density, large specific surface area, and high porosity, as well as provide more available adsorption sites by ZIF-67 polyhedrons, to facilitate pollutant adsorption from waste water. The prepared 3D ANF/ZIF-67 composite aerogel possessed favorable adsorption performance for heavy metal ions (250.95 and 183.29 mg/g for Cu 2+ and Cr 6+ , respectively) and organic dyes (199.36 and 65.98 mg/g for CV and MO, respectively), greatly exceeding that of the corresponding 3D ANF aerogel. Desorption experiments further demonstrated that up to 80% adsorption performance for heavy metal ions and organic dyes could be maintained after five times of usage. Hence, this research can provide new insights into the preparation of highly efficient adsorbents for water treatment.