Superhydrophilic carbonaceous-silver nanofibrous membrane for complex oil/water separation and removal of heavy metal ions, organic dyes and bacteria

Fouling has been the stubbornest challenge for the development of oil/water separation membranes. The commensal surfactants, heavy metals, organic foulants as well as microorganisms usually aggravate the membrane fouling. In this study, a superhydrophilic and underwater superoleophobic nanofibrous membrane with hydrogel-like surface was fabricated to tackle with the complex oil/water emulsion. Carbonaceous microspheres were covalently attached to the nanofiber surface and then trapped silver nanoparticles via in situ reduction to form carbonaceous-silver nanofibrous membrane. The fabricated membrane showed a permeability of 45612 ± 430 Lm-2h-1bar-1 for toluene-in-water emulsion with separation efficiency of higher than 99%. Moreover, it can remove above 90% Pb2+ through the adsorption of covalently attached carbonaceous microspheres and nearly 100% methylene blue through the Fenton-like oxidation of embedded silver nanoparticles. The gas bubbles generated from catalytic reaction promoted the floatation demulsification. In addition, the incorporated silver nanoparticles endowed the membrane with excellent antibacterial property towards to E. coil. The rational design of nanofibrous membrane aiming to fouling alleviation give more opportunities for the practical remediation of complex oil/water emulsions.