Preparation and characterization of nanotitania@fatty acid modified quartz sand proppant with super-hydrophobic and oleophilic properties

In this work, long-chain fatty acid (lauric acid (LA), myristate acid (MA) or stearic acid (SA))@nanotantia (TiO₂) composites (LATC, MATC and SATC) are applied to modify the surface of the quartz sand proppant (LATC@sand, MATC@sand, and SATC@sand proppant) to achieve excellent hydrophobic and oleophilic properties. The water contact angle (WCA) increases with increasing long chain length of the fatty acid. The WCA of SATC@sand proppant even reaches 157.9°, indicating a super-hydrophobic behavior. Moreover, after putting in boiling water for 4 hours, the SATC@sand proppant still exhibits super-hydrophobic property with WCA of 156.2°. Compared with LATC@sand and MATC@sand proppant, the SATC@sand proppant displays better thermal stability, and the thermal decomposition temperature of SATC@sand proppant is at about 170°C. Meanwhile, the SATC@sand proppant demonstrates relative lower acid solubility, bulk density (13.1 g/cm³) and apparent density (2.24 g/cm³) than raw sand proppant, indicating SATC@sand proppant shows great potential for using in hydraulic fracturing to increase petroleum production.