Synergistic effects of 2D graphene oxide nanosheets and 1D carbon nanotubes in the constructed 3D carbon aerogel for high performance pollutant removal

Abstract

To create interspace-enlarged and sites-exposed graphene-based adsorbents for pollutant management, three-dimensional macrostructures (3D GTs) were facilely constructed via self-assembly of two-dimensional graphene oxide nanosheets (2D GO) and one-dimensional carbon nanotubes (1D CNTs). Since the existence of CNTs acting like frames may reinforce the mechanical strength of the GO nanosheets, the density of the stable and porous 3D GTs was reduced to 0.2mg/mL which was much lower than the minimum concentration required to form pure GO 3D macrostructures. The 3D GTs exhibited superior adsorption capabilities to emerging pollutants such as oxytetracycline (1729mg/g) and diethyl phthalate (680mg/g), and traditional pollutants such as methylene blue (685mg/g), Cd2+ (235mg/g) and diesel (421g/g). The adsorption capacity of 3D GTs is higher than the reported graphene/GO and CNTs-based adsorbents, which can be attributed to the synergistic effects of GO and CNTs in micro-environment, nano-substrate, and active sites. Firstly, the assembled GO sheets were highly separated and in monolayer form, which created large interspaces in 3D GTs. Secondly, GO and CNTs provided abundant adsorption sites. Thirdly, the micro environment of interspaces in stable 3D GTs could be tuned to achieve selective adsorption to particular pollutant. In short, we propose a super graphene-based adsorbent which is competitive and scalable for water purification.