Cerium-Based Magnetic Y-Type Molecular Sieve for Deep Removal of Fluoride Ions from Water
With increasingly stringent discharge standards for fluoride-containing wastewater, there is an urgent need for cost-effective, easily operable adsorbents capable of rapid adsorption and separation for deep defluorination. In this study, a novel adsorbent, Ce-FMSY, was successfully prepared by co-precipitation of cerium (Ce) and Fe3O4 onto Y-type molecular sieve (MSY). The effects of Ce/Fe mass ratio, adsorption time, initial solution pH, and coexisting anions on adsorption performance were systematically investigated. Results showed that at a Ce loading of 1.0% and Ce/Fe mass ratio of 2:1, Ce-FMSY rapidly adsorbed 86.2% of F− within 30 min, with a maximum adsorption capacity of 4.139 mg·g−1. The saturated magnetization of Ce-FMSY was 13.4 emu·g−1, enabling rapid solid-liquid separation. The adsorbent maintained a stable fluoride removal rate of 77.1%–96.8% over an initial pH range of 3–9. Adsorption kinetics and isotherm fitting indicated that F− adsorption onto Ce-FMSY followed pseudo-second-order kinetics and the Freundlich model, suggesting chemisorption as the dominant mechanism, involving rapid diffusion, surface complexation, and valence transformation reactions. After five adsorption-desorption cycles, the adsorption capacity slightly decreased and then stabilized, with F− removal efficiency maintained at approximately 72.3% of the initial value. This study provides data support and theoretical reference for deep fluoride removal from wastewater.