A zeolitic imidazole framework (ZIF)–sponge composite prepared via a surfactant-assisted dip-coating method

Abstract

A rapid, simple and inexpensive dip-coating method is developed to prepare a three-dimensional hierarchical zeolitic imidazole framework (ZIF) composite using the commercially available melamine sponge as a support. With surfactant modification of sponge, self-assembling of ZIF nanocrystals on sponge skeletons is significantly facilitated and ZIF nanocrystals form a nearly uniform layer on sponge surfaces via electrostatic attraction and possibly π–π stacking interactions. The effect of surfactant type used to modify sponge is also investigated. The resultant ZIF–sponges exhibit strengthened mechanical strength (i.e., hardness) and improved hydrophilicity. ZIF–sponge also shows a remarkably high adsorption capacity for malachite green dye, a toxic pollutant, of 4093 mg g⁻¹ based on the Langmuir isotherm modelling analysis. ZIF–sponges can be designed and easily fabricated to be filters, membranes, and adsorbents. The approach demonstrated here may be also extended to prepare other types of ZIF or metal organic framework (MOF) sponges.