Preparation Of Graphene-based Hybrid Membrane With High Pervaporative Desulfurization Of Gasoline

With increasingly strict legislation has been focused on limiting the sulfur content in fossil fuel all over the world, highly efficient non-hydrodesulfurization technology with low energy cost is the key to producing clean oil fuel. Pervaporative desulfurization technology is one of the most promising desulfurization technology for commercial application, which requires high permeability, high selectivity and high stability for desulfurization membrane materials. With the traditional silicon rubber polydimethyl siloxane(PDMS) and a novel semicrystalline polymer polyether block polyamide(Pebax) as the major membrane material, a series of graphene-based hybrid membranes were fabricated via physically blending method. Aiming to overcoming trde-off effect and strengthening the desulfurization performance, different amount of fillers are incorporate into polymer matrix. An appropriate structure of polymer bulk matrix is constructed, resulting in an optimizaition crystallinity and free volume property. Through efficient loading facilitated transporter on the surface of GNS, render the facilitated transport function within the membranes. It is expected to possess long-term stability and better separation performance during the pervaporative desulfurization process. The details are summarized as follows:A series of polydimethyl siloxane-graphene nanosheets(PDMS-GNS) hybrid membranes were fabricated via physically blending method. An appropriate interfacial structure is constructed by incorporating GNS into PDMS, resulting in an increased fractional free volume. Moreover, the thiophene can be facilitated transport along the GNS because of ?-? interactions between GNS and thiophene. The hybrid membrane shows an optimum desulfurization performance with a permeation flux of 6.22 kg/(m2h)(65.9% higher than that of pure PDMS membrane) and an enrichment factor of 3.58(similar to that of pure PDMS membrane).A series of Pebax-PDA/GNS hybrid membranes were fabricated via physically blending method. The hydrophobicity of GNS are modified by the poly dopamine(PDA),which optimized the interfacial compatibility between Pebax and PDA/GNS. An appropriate structure of polymer bulk matrix is constructed by incorporating PDA/GNS into Pebax, resulting in a decreased crystallinity and an increased fractional free volume. Compared to the pure Pebax membrane, both the permeation flux and enrichment factor are increased. Especially, when the PDA/GNS content reaches 6 wt%, the permeation flux and enrichment factor are 3.94 kg/(m2h) and 7.73, respectively.The PDA layer on the surface of GNS can be used as a nanoscale guide to form uniform and highly dispersed Ag NPs on the surface. Decreasing the crystallinity of polymer matrix confers the optimization of membrane structures, leading to the intensification of diffusion process. In addition, the thiophene can be facilitated transport along the Ag@PDA/GNS due to the ?-complexion between Ag and thiophene. When the Ag@PDA/GNS content reaches 8 wt%, the hybrid membrane's degree is 12.9%(43.2% lower than that of pure Pebax membrane). The highest enrichment factor of 8.76 is obtained when the Ag@PDA/GNS content is 6 wt%. Higher permeation flux can be obtained at higher operation temperature, reaching a permeation flux of 22.53 kg/(m2h) and a enrichment factor of 6.07 at operation temperature of 343 K.