Adsorptive Removal of Industrial Dye by Nanoporous Zr porphyrinic Metal-Organic Framework Microcubes

Abstract

Increasing anthropogenic activities have adversely affected freshwater supply, making it an important global issue. Water resources are often contaminated by industrial dyes, which may harm both environment and human health even at low-level exposure. Herein, we report the adsorptive removal of a representative azo dye, methyl orange (MO) on PCN-224, a Zr porphyrinic metal-organic framework (MOF). Nanoporous PCN-224 has desirable structural characteristics such as an optimal pore aperture and a large pore volume optimized for trapping MO molecules, in addition to superior water stability. Significantly, through the combined investigation of experimental and theoretical studies, multiple adsorption sites such as the porphyrin linkers and Zr-6 nodes of the framework formed pi-pi interactions and hydrogen bonding with MO molecules, respectively, affording the highest adsorption capacity among the reported MOFs.