Surface modification of SiO2 nanoparticles to increase asphaltene adsorption

Metals and nonmetal nanoparticles, have been used for enhancing oil recoveries, deasphalting or catalyzing crude oil. The hydrophobicity, charge and polarizability of nanoparticles can modify their affinity to different molecules, e.g., asphaltenes. Modifying nanoparticle surfaces, changes their interactions with molecules, to improve their affinity and specificity. This work presents synthesis and use of surface-modified silica nanoparticles to increase asphaltene adsorptivity. SiO2 nanoparticles were synthetized and surface-modified with chitosan, carboxymethyl cellulose and polyethylene glycol 200. Surface-modified nanoparticles showed an enhanced adsorptivity compared with raw nanoparticles. Kinetics and thermodynamic experiments showed preferential interaction of modified nanoparticles with asphaltene subfraction.