Retracted Article: Enhanced adsorption of ionizable aromatic compounds on humic acid-coated carbonaceous adsorbents

Abstract

Adsorption of ionizable aromatic compounds (IACs) such as 1-naphthylamine and 1-naphthol on Humic acid (HA)-coated graphene oxide nanosheets (GONs), multiwalled carbon nanotubes (MWCNTs), activated carbon (AC), and flake graphite (FG) were investigated by the batch techniques. The adsorption of 1-naphthylamine on four HA-coated carbonaceous adsorbents was weakly depended on pH, whereas the adsorption of 1-naphthol on these HA-coated carbonaceous adsorbents evidently increased with increasing pH from 2.0 to 8.0. The maximum adsorption capacity of HA-coated carbonaceous adsorbents for IACs was in the order of GONs≫MWCNTs>AC>FG, indicating that the GONs can be regarded as a suitable material for the preconcentration and removal of IACs from aqueous solution in environmental pollution management. The main adsorption mechanism between carbonaceous adsorbents and IACs is the hydrophobic effect. This observation is of great implication for the removal of IACs by HA-coated carbonaceous adsorbents in environmental applications.