Carbon derived nanomaterials for the sorption of heavy metals from aqueous solution: a review

Abstract

In many parts of the world, clean water has become a useful resource owing to an increase in the human population, industrialization, and civilization expansion. But, civilization expansion, growth in population, and industrialization have set off a continual deterioration of available quality of water resources, with water contamination having an adverse effect on concerned societies economic growth and social viewpoints. Carbon nanomaterials have great potential as a novel adsorbent for heavy metal ions sequestration owing to their high surface area, three-dimensional structure, carbon large quantity, chemical stability, and their negligible mass density. From reviews of previous studies using carbon nanomaterials for toxic metals removal, most adsorption experimental processes were best depicted using the Langmuir isotherm and pseudo-second-order kinetic models, with the maximum sorption capacity of toxic metals removed using this carbon nanomaterials in the order of carbon nanotubes > graphene > activated carbon > carbon dots and carbon quantum dot. Also, the sorption of toxic metals onto most carbon nanomaterials was dependent on the magnetic field applied as well as the solution pH and the distribution of adsorbate species at various pH, with the adsorption of anion and cation metal species favourable when the sorbent surface was positive and negative charged owing to the respective point of zero charge (pHpzc) of the various carbon nanosorbents.