Incorporation of negatively charged MWCNT-fGO self-assembled nanomaterials into PLA polymeric membranes for wastewater treatment

The incorporation of nanomaterials in membrane’s matrix aims mainly to improve the properties of the membranes such as hydrophilicity, mechanical strength, thermal stability, water flux. Multi-walled carbon nanotubes (MWCNT) and functionalized graphene oxide (fGO) have recently attracted attention, as they have proved to have potential in various applications. In this study, self-assembled MWCNT-fGO nanocomposite was synthesized and used as a filler in environmentally-friendly polylactic acid (PLA) membranes. The membranes were fabricated following the phase inversion method with different concentrations of MWCNT-fGO (2, 4, 6 and 8 wt.%). In addition, the membranes were tested for the removal of heavy metal ions from wastewater. The results showed that a considerable removal can be achieved using the composite membranes. For instance, the highest Cu2+, Ni2+ and Zn2+ removal (e.g., 89%, 35%, and 39%, respectively) was observed in the 8 wt.% MWCNT-fGO PLA membrane. This was achieved at water flux of 850 L·m-2·h-1 (LMH). On the other hand, the pristine PLA membrane water flux was around 450 LMH and was capable of achieving 82, 25, and 30% rejections for Cu2+, Ni2+ and Zn2+, respectively. These results showed the potential of the MWCNT-fGO PLA membranes application in treating heavy-metal containing wastewater.