Removal of nickel (II) from aqueous solution by graphene and boron nitride nanosheets

Molecular dynamics simulations were carried out to study the removal of Ni2+ as a heavy metal from the water by the functionalized graphene nanosheet (GNS) and boron nitride nanosheet (BNNS). Nickel causes asthma, conjunctivitis and inflammatory reactions and nickel salts act as emetics when swallowed; therefore, removal of nickel is necessary from the aqueous solutions. The systems were comprised of a nanosheet (GNS or BNNS) with a pore in its center that it is containing an aqueous ionic solution of nickel chloride. For the removal of Ni2+ from an aqueous solution, the pores of nanosheet were functionalized by passivating each atom at the pores edge and then an external electric field was applied along the z-axis of the simulated system. To justify the passage of ions through the pores, the potential of the mean force (PMF) of ions was calculated. To evaluate the properties of the system, the ion retention time and the radial distribution functions of species were measured. Based on the findings of this study, these nanostructure membranes can be recommended as a model for removal of heavy metals

Separation of methane from different gas mixtures using modified silicon carbide nanosheet: micro and macro scale numerical studies

This research discusses the separation of methane gas from three different gas mixtures, CH4/H2S, CH4/N-2 and CH4/CO2, using a modified silicon carbide nanosheet (SiCNS) membrane using both molecular dynamics (MD) and computational fluid dynamics (CFD) methods. The research examines the effects of different structures of the SiCNSs on the separation of these gas mixtures. Various parameters including the potential of the mean force, separation factor, permeation rate, selectivity and diffusivity arc discussed in detail. Our MD simulations showed that the separation of CH4/N-2 and CH4/CO2 mixtures was successful, while simulation demonstrated a poor result for the CH4/N-2 mixture. The effect of temperature on the diffusivity of gas is also discussed, and a correlation is introduced for diffusivity as a function of temperature. The evaluated value for diffusivity is then used in the CFD method to investigate the permeation rate of gas mixtures