Preparation of Vanadium Tailings-Based Ceramsite and Evaluation of Its Adsorption Performance for High-Fluoride Wastewater

Vanadium tailings-based ceramsite (VT-Ceramsite), a type of porous ceramsite synthesized from vanadium tailings, was employed for the adsorption of fluoride ions from high-fluoride wastewater. This approach not only mitigates environmental pollution caused by industrial solid waste but also effectively removes fluoride contaminants from wastewater. The effects of vanadium tailings content, sintering temperature, and sintering time on the adsorption performance of the VT-Ceramsite were systematically investigated. Comprehensive characterizations via XRD, SEM, BET, and adsorption modeling reveal that fluoride sequestration by VT-Ceramsite is governed by the synergy between physical diffusion and chemical interactions. While the porous architecture provides essential transport pathways, the chemically active sites facilitate stable bonding. Future research will prioritize surface functionalization and tailoring strategies to augment the density of these active sites, thereby maximizing the adsorption potential for treating complex industrial effluents. The optimal preparation conditions were determined to be a ratio of 6.5:2.5:1 for vanadium tailings, fly ash, and kaolin, with a preheating temperature of 300 °C for 20 min and a sintering temperature of 900 °C for 20 min. In these conditions, the adsorption capacity for fluorine ions can reach 43.59 mg/g. VT-Ceramsite exhibited a specific surface area of 3.61 m2/g, hydrochloric acid solubility of 1.2%, and a void fraction of 48.68%, all parameters met national industrial standards. In addition, the leaching concentrations of heavy metals were found to be well below the limits specified in CJ/T 299-2008, indicating that the material poses no risk of secondary pollution. The study provides an economical, safe, and environmentally friendly route for the utilization of solid waste, and it offers a promising adsorbent for treating high-fluoride wastewater.