Expanding the environmental applications of metal (Al, Ti, Mn, Fe) doped graphene: adsorption and removal of 1,4-dioxane.

The potential applications of Al, Ti, Mn and Fe-doped graphene for environmental remediation of 1,4-dioxane (a critical pollutant and toxic compound) are analyzed in detail in the framework of density functional theory calculations. 1,4-Dioxane is a highly mobile and soluble pollutant and developing new strategies for its adsorption and subsequent removal becomes an important issue. All the systems were fully optimized and analyzed in their most stable spin states. The results determined that the proposed doped-graphene materials enhance the interaction with 1,4-dioxane compared to intrinsic graphene, with adsorption energies in the range of 1.2-1.6 eV. The high stability of the adsorbent-dioxane interactions is fully discussed in terms of chemical metal-dioxane binding, charge transfer and long-range interactions. The adsorbent-dioxane adsorption is also accompanied by changes in the electronic structure with respect to the isolated substrates, which are larger for Mn and Fe as dopants. Ab initio molecular dynamics simulations also show that the adsorbent-adsorbate interactions remain strong at room temperature (300 K). Finally, implicit/explicit solvent methodologies were implemented to get insights into the effects of aqueous environments on the adsorption strength, which shows the high stability of interaction in water, sorting the sorption efficiency as AlG ≈ FeG > MnG ≈ TiG. From these new insights, Al, Ti, Mn and Fe-doped graphene emerge as new potential materials to be applied in technologies related to the removal of 1,4-dioxane.