Fabrication of Ultrafiltration Membranes from PAN Composites and Hydrophilic Particles for Isolation of Heavy Oil Components

Abstract

Membranes have been fabricated from polyacrylonitrile (PAN) doped with graphene oxide (GO) particles, PAN pyrolyzed by IR irradiation (IR-PAN-a), and nanodiamonds (ND). The pore structure of the resulting membranes has been studied. It has been shown that the addition of carbonaceous components slightly reduces the average pore size of the membranes from 17 to 12–15 nm, thereby leading to a decrease in the water permeability of membranes from 158 to 80.9–119.9 kg/(m² h atm). Doping with particulate additives led to surface hydrophilization: the contact angle of water decreased from 65° to 48°–55°, facilitating the flow of crude oil solutions in toluene by a factor of 2–3 compared to the PAN membrane. However, the addition of GO or IR-PAN-a promoted a significant increase in irreversible membrane fouling. On the other hand, the addition of nanodiamonds not only reduced the overall fouling of the membrane and increased the permeability of the feed mixture from 4.93 to 8.47 kg/(m² h atm), but also made it possible to recover more than 96% of the pure toluene flux. The rejection ratio of ND-doped membranes during the filtration of 10 g/L oil solutions in toluene was 85–89%.