Rapid hydrate-based methane storage promoted by bilayer surfactant-coated Fe3O4 nanoparticles under a magnetic field

Abstract

Natural gas hydrate technologies have been perceived as promising methods of natural gas storage and transportation. Rapid achievement of high gas storage is the primary objective of hydrate applications. In this work, Fe3O4 nanoparticles were synthesized and surface-modified by sodium oleate (SO) and sodium dodecyl sulfate (SDS) bilayer molecules (hereafter SDS&SO@Fe3O4). The prepared SDS&SO@Fe3O4 nanosuspensions exhibited sufficient water dispersion stability and were utilized as promoters for hydrate-based methane storage. The composite promoter exerted apparent higher methane storage capacity and hydrate formation rate than pure SDS solution. The maximum storage capacity with SDS&SO@Fe3O4 was 156.5 v/v and the whole hydration process could be completed in only 32 min. Moreover, magnetic fields were successfully introduced to the reaction system, which exhibited a further promotion to hydrate formation due to the regular arrangement of SDS&SO@Fe3O4. In the presence of a magnetic field, the major superiority was that induction period together with the total hydration period were prominently shortened and the induction time was negligible when the magnetic intensity exceeded 193 mT. In summary, the bilayer surfactant-coated Fe3O4 nanoparticles developed in this study led to substantial improvements in methane hydrate formation kinetics and therefore have great potential in industrial applications involving hydrate-based energy storage.