Adsorption of PFAS on Bridged Functionalized Organosilica Materials

PFAS are hazardous contaminants that have a devastating impact on human health and the environment. Their hazardous nature has led to the development of various adsorption methods for removing these contaminants from water sources. In this study, functionalized organosilica materials were synthesized from bis[3-(trimethoxysilyl)propyl] amine using the sol-gel method. The surface amino groups of the organosilica were converted into amine hydrochloride groups. Their adsorption properties were evaluated using salts of perfluorooctanoic acid, perfluorooctanesulfonic acid, and perfluorobutanesulfonic acid. Results showed excellent adsorption capacity of the materials. Adsorption of PFAS leads to particle agglomeration and flotation of the spent material. A column test showed the presence of two types of adsorption sites with different accessibility. Adsorbed PFAS are easily desorbed from the organosilica with aqueous sodium hydroxide solution. The results obtained suggest that the organosilica can be used in filtration devices for efficient removal of PFAS contaminants from water.