Risk assessment of ethylhexyl dimethyl PABA in sunscreen cosmetic products

Abstract

In this study, we use density functional theory (DFT) calculations and molecular dynamics (MD) simulations to investigate the performance of graphenylene–1 membrane for hydrogen (H2) purification and helium (He) separation. The stability of this membrane is confirmed by calculating its cohesive energy and phonon dispersion spectra. Our results show that there is a surmountable energy barrier for H2 molecule (0.384 eV) and He atom (0.178 eV) passing through graphenylene–1 membrane. At room temperature, the selectivity of H2/CO2, H2/N2, H2/CO and H2/CH4 are obtained as 3×1027, 2×1018, 1×1017 and 6×1046, respectively. Furthermore, we demonstrate that graphenylene–1 membrane exhibits amounts of permeance for H2 and He that are much higher than the value of them in the current industrial applications especially at temperatures above 300 K and 150 K, respectively. We further performed MD simulations to confirm the results of DFT calculations. All these results show that graphenylene–1 monolayer is an excellent candidate for H2 purification and He separation.