Preparation of modified montmorillonite with different quaternary ammonium salts and application in Pickering emulsion

Abstract

A Pickering emulsion stabilized with organophilic montmorillonite clay mineral (OMMTs) has potential applications in reducing radiation exposure as montmorillonite (MMT) can effectively slow down the migration of nuclides. In order to obtain more stable Pickering emulsions, OMMTs were prepared using quaternary ammonium salts of different carbon chain lengths, namely, dodecyltrimethylammonium chloride (DTAC), cetyltrimethylammonium chloride (CTAC), stearyltrimethylammoniumchloride (STAC) and dioctadecyldimethylammonium chloride (DODMAC). The OMMTs were characterized by FT-IR, XRD, TGA, and SEM and a three-phase contact angle-measuring instrument. Stable W/O Pickering emulsions were prepared using modified montmorillonite as the emulsifier and white oil as the oil phase. The results showed that the quaternary ammonium salt was successfully inserted into the middle of the sheet of MMT, which reduced the hydrophilicity of MMT. The emulsions stabilized with OMMTs exhibited better stability than the emulsions stabilized with surfactants. The use of OMMTs reduced the average particle size of the emulsion and enhanced emulsion stability. With the increase in the carbon chain length of the modifier, the stability of the Pickering emulsion improved.