Adsorption of organic pollutants by nanomaterial-based adsorbents: An overview

Nanomaterial-based adsorbents have garnered increasing attention in water and wastewaters treatment applications due to their attractive properties and strong adsorption capabilities for various organic compounds. The current review appraises the use of nanomaterial adsorbents (NAs); namely: carbon nanotubes (CNTs), graphene sheets (GS), and metal oxides (MO) for environmental remediation applications. The adsorption capacities for organic dyes, aromatic compounds, phenolic derivatives, pharmaceuticals, and antibiotics are comprehensively reviewed. The current study critically investigates the role of physicochemical properties of the adsorbents, solution chemistry of the adsorbates, and the uptake mechanism on the sorption performance of NAs. The adsorption isotherms reveal Langmuir and Freundlich models to be the best fit of the experimental data in most of the studies, whilst the adsorption kinetics is well described by the pseudo-second-order model. This review attempts to present a prior knowledge about the adsorption capability of CNTs, GS, and MO for the removal of organic pollutants (OPs) from wastewaters by assessing outcomes of peer-reviewed articles published between 2000 and 2019.