Enhanced removal of Cu(II) ions from aqueous solution by in-situ synthesis of zeolitic imidazolate framework-67@wood aerogel composite adsorbent

Abstract

ABSTRACT Zeolitic imidazolate frameworks (ZIFs) were considered to be one of the most promising emerging nanoporous adsorbents capable of efficiently removing a variety of heavy metals ions from wastewater. However, due to the powdered crystalline state, easy aggregation and instability of ZIFs materials, their actual large-scale applications in water matrices are significantly hindered. Compounding ZIFs with self-supporting porous wood aerogel (WA) to obtain advanced composites is excepted to further enhance their adsorption performance with higher practicability. Herein, a novel Zeolitic Imidazolate Framework-67 (ZIF-67)@wood aerogel (denoted as ZIF-67@WA) adsorbent for efficient capture of Cu(II) ions was successfully fabricated via in situ growth of Cobalt-based ZIF-67 particles onto the WA scaffold. Benefiting from the integration of unique three-dimensional porous structures and abundant accessible active sites, the obtained ZIF-67@WA hybrids exhibited fast adsorption kinetics and the maximum adsorption capacity towards Cu(II) calculated from the Langmuir model was 254.84 mg g−1. The adsorption kinetic and isotherm studies were consistent with pseudo-second-order model (R 2 = 0.991) and Langmuir model (R 2 = 0.973), indicating the adsorption of Cu(II) was a monolayer chemisorption process. This work proposed a new route for designing and constructing functionalized MOF@biomass hybrid materials for heavy metal wastewater treatment.