Surface synthesis of a polyethylene glutaraldehyde coating for improving the oil removal from wastewater of microfiltration carbon membranes

Development of hydrophilic microfiltration carbon membrane (MFCM) is essential for improving the separation performance of oil-water emulsion. In this work, a strategy was proposed to modify the microstructure and property of MFCM by surface synthesizing a hydrophilic polyethylene glutaraldehyde (PVG) coating. The thermal stability, functional groups, morphology and porous structure of modified MFCM were characterized by thermogravimetric analyzer, Fourier transform infrared spectroscopy, scanning electron microscope and general weight difference/filtration velocity techniques, respectively. The effects of coating types, coating solution concentration on the structure and separation performance of MFCM for oily wastewater were investigated. The results showed that the surface PVG coating was sufficiently stable to resist the aggressive system of oily wastewater. Both water permeation flux and oil rejection were significantly improved for MFCM after modification. Moreover, the water permeation flux and oil rejection of MFCM respectively decreased and increased as the concentration of coating solution was increased. The maximum oil rejection reached to 94.8% for MFCM modified with a PVG surface layer formed by coating a starting solution of 9%, along with a permeation flux of 691.1 kg/m2 h MPa.