A sulfur, nitrogen dual-doped porous graphene nanohybrid for ultraselective Hg(ii) separation over Pb(ii) and Cu(ii). Issue 31 (31st July 2020) - Tian, Hua
Abstract : A specific 2D porous nanostructure and multi-binding ligands endow SNPG with outstanding selectivity and ability to separate Hg(ii ) over Pb(ii ) and Cu(ii ). Abstract : Two-dimensional (2D) porous graphene is attractive as a high-permeability membrane for ionic and molecular separation. Here, we propose a sulfur, nitrogen dual-doped 2D porous graphene (SNPG) nanohybrid by adopting a facile one-step process. The resulting sandwich-like porous nanohybrid features uniform ion-gated nanopores for efficient transport of target heavy metal ions while blocking undesired ions, as well as abundant multi-binding ligands for selectively chelating permeated heavy metal ions. We show from systematic experiments that this SNPG nanohybrid exhibits outstanding selectivity and ability to separate Hg(ii ) ions in mixtures with eight other metal ions. An excellent uptake capability (803 mg g −1 ) and high removal ability (>99%) within the entire pH range of 2–10 can be obtained. Given the specific 2D porous nanostructure and specific binding ligands, SNPG exhibits an ultrahigh separation factor towards Hg(ii ) that is up to four orders of magnitude higher than those of Pb(ii ), Cd(ii ) and Cu(ii ) ions, significantly higher than those of most reported adsorbents. These findings provide a new opportunity to develop selective materials and devices for applications such as efficient recognition, extraction and separation of target metal ions in complex aqueous environments.