Graphene oxide (GO)-coated microbubble flotation for polycyclic aromatic hydrocarbon (PAH) removal from aqueous solutions

Abstract

This research aims to synthesize graphene oxide (GO)-coated microbubbles to enhance polycyclic aromatic hydrocarbon (PAH) removal from aqueous solutions through flotation technology. In this research, 1-Dodecyl-3-methylimidazolium chloride ionic liquid ([C12mim]Cl) was used to bridge microbubbles and GO. The attachment between microbubbles and GO in [C12mim]Cl solution was successfully observed and quantified using a microscopy visualization technique and UV–VIS Spectrophotometer respectively. The synthesised GO-coated microbubbles were then used to enhance the removal of phenanthrene (PHEN) and pyrene (PYR), a low and high molecular weight PAH respectively, from aqueous solutions via flotation technology. A closed loop laboratory-scale flotation system was developed to compare the PAH removal efficiency by uncoated and GO-coated microbubbles. The PHEN and PYR removal efficiencies increased significantly to 64.77% and 74.01%, respectively for GO-coated microbubbles as compared to uncoated microbubbles of 18.91% and 19.65%, respectively during flotation. Furthermore, the higher removal efficiency of PYR compared to PHEN implied that GO-coated microbubbles were more efficient at removing higher molecular weight PAHs (more hydrophobic) which are more detrimental to the environment