Efficient fluoride recovery from wastewater using mesoporous Ca-based nanomaterials derived from municipal solid waste incineration fly ash via fluidized bed crystallization.

This study introduces an innovative approach utilizing mesoporous Ca-based nanomaterial (MCN) derived from municipal solid waste incineration (MSWI) fly ash as carriers in a fluidized bed crystallization (FBC) process for the recovery of fluoride from semiconductor wastewater. The transformation of nonporous MSWI fly ash into mesoporous structures was achieved through facile treatments, including ultrasonic-assisted leaching with ethylenediaminetetraacetic acid disodium salt dihydrate (EDTA–Na) and surface modification with sodium silicate, enhancing surface functionalities and active site formation. The resulting MCN exhibited a significant surface area of 222.0 m²/g, ideal for fluoride recovery. When tested with synthetic wastewater, the recovery efficiency and crystallization ratio of fluoride using MCN in the FBC system reached 99.0 % and 93.3 %, respectively. Further investigation revealed that the unique surface properties and large surface area of the MCN promoted the crystallization of fluoride-containing precipitates, resulting in homogeneously nucleated cubic CaF 2 crystals and facilitating layer-by-layer crystal growth. Testing the FBC process with real semiconductor wastewater resulted in a crystallization efficiency of 94.5 %, with the CaF 2 content in the recovered precipitates reaching 84.3±0.7 %. These findings highlight the potential of MCN as an innovative carrier for fluoride recovery, demonstrating a novel and environmentally friendly method for converting waste into valuable materials. This study offers a promising solution for treating fluoride-contaminated wastewater, with high potential to revolutionize industrial wastewater management and promote a circular economy. [Display omitted] • Developed mesoporous Ca-based nanomaterials (MCN) for FBC fluoride recovery. • MCN carriers achieved 99.0 % fluoride recovery and 93.3 % crystallization ratio. • MCN derived from waste reduces environmental impact in the FBC process. • MCN offers a cost-effective alternative to silica sand for fluoride removal in FBC. [ABSTRACT FROM AUTHOR]