Summary and future work
A number of advanced adsorbents, including nanostructured metal oxides, carbon nanotubes, porous boron nitride nanosheets and porous graphene have been developed recently to enhance adsorption capacity, selectivity and regeneration ability. These nanostructured adsorbents have attracted much attention as one of nanotechnology applications. However, nanoparticles cannot be packed in a column due to the high pressure drop they cause. Hence, nanoparticles have to be either embedded in or coated on the surface of larger particles, by which the merit of nanoparticles is largely compromised. Incorporation of nanoparticles in nanofbrous membrane can circumvent this problem due to nanofber’s large surface area and porosity, which, respectively, allow high adsorption and high fltration capacity. When embedded in nanofbers, however, adsorption efciency of nanoparticles is signifcantly diminished. A technique should be developed to attach nanoparticles to the nanofber surface, while preventing the leaching of nanoparticles during fltration.
Another challenge is to establish an appropriate mathematical model for MA operation. Currently, in most MA works, adsorption isotherm and kinetics are the only parameters to characterize MA membranes. A set of more powerful MA membrane characterization parameters should be found to optimize the membrane defunctionalized graphene as a nanostructured membrane for removal of copper and mercury from aqueous solution: a molecular dynamics simulation study.
