Amine-functionalized UiO-66 incorporated electrospun cellulose/chitosan porous nanofibrous membranes for removing copper ions

Abstract

Cellulose (CE)/chitosan (CS)/amine-functionalized zirconium 1, 4-dicarboxybenzene metal–organic framework (UiO-66-NH2) porous nanofiber membranes were prepared by direct electrospinning and surface in-situ growth and then used to remove copper ions (Cu2+) from polluted water. The micro-morphology, porosity, thermal stability, chemical groups, crystallographic structure, and adsorption performance of CE/CS/UiO-66-NH2 nanofibrous membranes were characterized. The hydrophilicity, thermal stability, and adsorption capacity of the membranes were greatly improved by incorporating UiO-66-NH2. The direct electrospinning CE/CS/UiO-66-NH2 nanofibers displayed the irregular, bumpy shapes and large fiber diameters (768.99–1039.74 nm). They also increased the chemical active sites due to the effective and uniform combination of UiO-66-NH2 with nanofibers. This resulted in a superior adsorption performance than the one with in-situ preparation. The CE/CS/UiO-66-NH2-5 showed the highest adsorption capacity of 121.16 mg g−1 and a removal rate of 90.69 %. The optimal Cu2+ adsorption conditions were obtained at an initial Cu2+ concentration of 100 mg L-1 and in weakly acidic media (pH = 5). The Langmuir model was optimal to describe Cu2+ adsorption of the nanofibrous membranes. The adsorption process involved both physical adsorption with chemical adsorption. This provides a novel strategy to combine metal–organic frameworks with the natural biomasses via electrospinning, which shows a promising application for efficient remediation of heavy metal ions in wastewater.