Abstract
Silicon carbide (SiC) foam ceramics demonstrate excellent filtration efficiency as filter supports due to their complex pore network and chemical stability. However, their fabrication demands high sintering temperatures (above 2100 °C), resulting in substantial energy consumption and production costs, which restricts their wider use in separation and purification application processes. To address this, we utilized fly ash, a by-product of coal combustion rich in inorganic Al₂O₃, as a sintering aid to develop a porous silicon carbide–alumina foam ceramic (SAFC) and investigated the effects of Al₂O₃ on its performance. Additionally, we introduced SAFC as an adsorbent material, synthesizing the fluoride adsorbent (La@SAFC) and evaluating its fluoride removal efficacy through batch experiments. Results indicate that Al₂O₃, as a sintering aid, promotes the sintering process by forming a liquid phase that enhances Si and C diffusion at lower sintering temperatures. SAFC containing 16 wt.% Al₂O₃ achieved optimal porosity, low bulk density, and compressive strength at a sintering temperature of 1150 °C. The addition of Al₂O₃ also facilitated mullite formation, significantly enhancing the ceramic's mechanical properties. However, excess Al₂O₃ can produce an overabundant liquid phase and gas release, potentially compromising the mechanical integrity of SAFC. Batch experiments revealed that La@SAFC exhibited strong fluoride removal from water containing competing ions across a pH range of 3–7, achieving effluent within strict discharge standards. Mechanism analysis suggested fluoride removal via ion exchange and electrostatic interaction. La@SAFC maintained high fluoride removal efficiency across five regeneration cycles, underscoring its promise for practical applications.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call