Preparation Of Self-dispersing Surface Modified SiO₂ And The Adsorption Characteristic On The Oil-Water Interface

The influence of formation temperature and salinity on silica nanoparticles is small.Silica nanoparticles have special properties.They can solve the problems that cannot be solved in the field of traditional petroleum exploitation,especially in improving interfacial activity and adjusting wettability to improve recovery.The application of silica nanoparticles is seriously limited because of its strong hydrophilicity,large specific surface area and poor dispersion.Hence,the surface of silica nanoparticles was modified by suitable surface modifier,in order to prevent agglomeration,improve dispersion,rheological properties and physical and chemical properties.This is of great significance for the application of silica nanoparticles.In this paper,surface modification of silica nanoparticles was studied by chemical surface modification technology.Water based active silica nanoparticles will be prepared with properties of easy access,good interfacial activity and self-stabilized dispersion.Transmission electron microscope and Fourier transform infrared spectrometer were used to observe the morphology and surface components of silica nanoparticles.The dispersion stability,oil-water interfacial activity and emulsification performance of the modified silica nanoparticles were evaluated by using dynamic light scatterometer,rotating drop interfacial tensiometer and interfacial rheometer.The interfacial rheological properties and adsorption characteristic on the oil-water interface under different influence factors(concentration,temperature,oscillation frequency,etc.)were investigated.The mechanism of Pickering emulsion stabilized by modified silica nanoparticles was clarified.The modified silica nanoparticles had well dispersibility and stability in water,with an average size of 28 nm and ? potential of-58.34 m V.The modified silica nanoparticles showed significant ability on reducing interface tension and improving dilatational modulus.A better emulsion stability was achieved by using the nanoparticles as the emulsion stabilizer.The nanofluid(1 wt%)could improve the modulus to 154.5 m N/m.The interface film shows obvious elastic properties because of the adsorption of modified silica nanoparticles on the interface.The content of modified silica nanoparticles dispersed in water directly affects the stability of the emulsion.The higher the concentration is,the more stable the emulsion is.With the increase of the concentration of salt,the stability of the emulsion increased first and then decreased.When the concentration of salt was 4%,the number of droplets in the emulsion was the smallest.