An electrospun fiber based metal–organic framework composite membrane for fast, continuous, and simultaneous removal of insoluble and soluble contaminants from water

Abstract

Removal of soluble organic pollutants and insoluble oil from wastewater has received much attention recently. However, the simultaneous elimination of these two kinds of contaminants is still a challenge. Here, we present a simple approach for the large-scale fabrication of a porous metal–organic framework (MIL-100(Fe)) uniformly grown onto an electrospun polyacrylonitrile (PAN) fiber membrane (PAN@MIL-100(Fe) FM) via electrospinning and hydrothermal reactions. The MIL-100(Fe) loading is up to 58.2%. Because of the binding ability of MIL-100(Fe), PAN@MIL-100(Fe) FM can remove the food additives amaranth red (AR) and vanillic aldehyde (VA) through membrane filtration. The breakthrough volumes for AR and VA by 3.1 cm² (thickness = 120 μm) of PAN@MIL-100(Fe) FM are 221 mL and 172 mL (pollutant concentration decreases to 0.1 mg L⁻¹ from 10 mg L⁻¹), respectively. Moreover, the MIL-100(Fe) growth leads to construction of a coarse surface on the electrospun fiber, which endows the membrane with underwater superoleophobicity properties and anti-oil-fouling performance. As a result, soybean oil can be removed from an oil/water mixture with a separation efficiency of 99.8%. Furthermore, the PAN@MIL-100(Fe) FM is used for the purification of simulated food wastewater containing AR (5 mg L⁻¹), VA (5 mg L⁻¹) and soybean oil (1 vol%) via one-step filtration. The simultaneous removal efficiencies toward the three pollutants are all above 99.0%. In addition, the removal efficiencies can be well maintained after five filtration cycles. The high separation efficiency, good recyclability and large-scale production make the PAN@MIL-100(Fe) FM a promising material for multifunctional wastewater treatment.