Novel electrospun ZIF/PcH nanofibrous membranes for enhanced performance of membrane distillation for salty and dyeing wastewater treatment

Abstract

Membrane distillation (MD) has many attractive advantages such as high rejection, low operating temperature, and has shown great potential for salty and dyeing wastewater treatment. However, the existing MD membranes often suffers from low permeability and membrane pore wetting issue, which significantly limit its practical applications. Herein, Zeolitic imidazolate framework 71 (ZIF-71) was doped in poly (vinylidene fluoride-co-hexafluoropropylene) (PcH) to prepare a hydrophobic electrospun nanofibrous membrane for MD process. The incorporation of ZIF-71 nanoparticles not only improve the surface roughness and hydrophobicity of the original PcH nanofiber membrane, but also increase the permeation flux (19.2 L m−2 h−1) and desalination performance (>99.99%) of the MD membrane. What's more, ZIF/PcH membrane was used to treat salty and dyeing wastewater, still showing high permeation flux, excellent pollutant retention rate and high stability. The desalination and decolorization rate of the treated wastewater can reach more than 99.5%, and the COD removal rate can reach 99.12%. The present study suggested that ZIF-doped electrospun nanofiber membrane provide high potential applications for direct contact membrane distillation (DCMD) desalination.