Preparation of CeO2@SiO2 Microspheres by a Non-sintering Strategy for Highly Selective and Continuous Adsorption of Fluoride Ions from Wastewater

High-performance composite materials with an environment-friendly and cost-effective nature are attracting much attention in environmental pollution abatement. In this study, a novel CeO2@SiO2, adsorbent was prepared via a novel approach based on vacuum rotary evaporation and co-precipitation following a non-sintering strategy avoiding the application of high-temperature calcination with very simplified mechanization. The fabricated CeO2@SiO2 was applied for the adsorption of ions from wastewater achieving much higher adsorption efficiency (257.7-363.9 mg/g (298-338 K)) than many reported adsorbents. In addition to this, CeO2@SiO2 realized high selectivity for ions (residual concentration of less than 1.5 mg/L) under the presence of NO3-, SO42-, and Cl- as counteranions as a simulated system. Concurrently, CeO2@SiO2 adsorbents also realized excellent adsorption performance in real seawater and tap water. The used adsorbent was easily regenerated via desorption in NaOH solutions and could be reused for four consecutive cycles with minimal loss in adsorption efficiency. This study provides an alternative, promising, cost-effective, convenient, and highly efficient CeO2@SiO2 microsphere adsorbent for the abatement of F- from wastewater, both in the presence and absence of counteranions.