Electrospun silica nanofiber mats functionalized with ceria nanoparticles for water decontamination

Abstract

This study demonstrates the fabrication of nanoceria-immobilized silica nanofibers for efficient water decontamination with easy reuse and regeneration properties. Commercially-available ceria (CeO₂) nanoparticles were immobilized on electrospun silica nanofiber mats. Optimal conditions for both oxidation of model trace organic compounds (TrOCs) and hydroxyl-radical formation were determined in batch experiments with ceria nanoparticles. Kinetic experiments showed comparable oxidation rates of positively- and neutrally-charged TrOCs (95 and 98%, respectively) by the nanofiber composites at pH 2 in 0.5 mM H₂O₂. We demonstrated the reuse properties of the ceria nanofiber composites, finding less than a 15% reduction in oxidation performance after 10 cycles. In addition to this oxidative performance, the electrospun CeO₂ nanofiber composites are also applicable for adsorbing the persistent contaminant perfluorooctanesulfonic acid (PFOS) through electrostatic interactions. Regeneration of the fibers was enabled through a one-hour heat treatment at 550 °C in air. Overall, results from this study show that the nanoceria-immobilized silica nanofibers can be used as efficient oxidative and adsorptive media to treat TrOCs in acidic waters, without use of an additional catalyst separation stage from solution.