Abstract: Functional modification of surface of SiO₂ nanoparticles (SN) with 1H,1H,2H,2H-perfluoro-octanetrimethoxysilane was conducted,and corrosion resisting super hydrophobic SiO₂ nanoparticles (SiN-F) were prepared.Then “dry concentrated sulfuric acid”,which is sulfuric acid encapsulated in air inverse phase bubbles was prepared by mixing SN-F and 90% concentrated sulfuric acid under high speed stirring.The effect of the dosage of SN-F on formation of “dry concentrated sulfuric acid” was examined.Result shows that when the dosage of SN-F is 5% of the mass of concentrated sulfuric acid,morphology of the “dry concentrated sulfuric acid” is uniform spherical with particle size of 100-200 μm.The prepared “dry concentrated sulfuric acid” displays high specific surface area and certain mechanical strength.After 18 months,its morphology and properties remain unchanged.The method provides new opportunities for safety in transportation,storage and chemical reaction operations in industrial applications of concentrated sulfuric acid.

Key words: gas-liquid interface, interfacial adsorption, concentrated sulfuric acid, encapsulate, super hydrophobic silica