Removal and recovery of fluoride from wastewater via mixed calcium salts by fluidized bed induced crystallization technology

IF 8.1 1区工程技术 Q1 ENGINEERING, CHEMICAL

Separation and Purification Technology Pub Date : 2025-01-23 DOI:10.1016/j.seppur.2025.131773

Zhipeng Gao, Yuming Tian, Jianglei Xiong, Hong Yu, Qiuhong Xiang, Jigang Shen, Cheng Liu

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引用次数: 0

Abstract

To overcome the disadvantages of high sludge production and the inability to collect calcium fluoride caused by chemical precipitation for defluoridation, the performance of fluidized bed induced crystallization (FBC) with fluorite particles as crystal seeds was investigated for the removal and resource recovery of fluoride (F^-) from wastewater. The effects of parametric factors were explored, and the optimal operating conditions were: [Ca²⁺]:[F^-] molar ratio of 0.5, fluoride load of influent of 4 kg/(m²·h), up-flow velocity of 6.5 m/h and initial bed height of 0.6 m. The pilot-scale experiment showed that the mixed calcium salts scheme and the automated system could overcome the adverse impacts caused by influent pH fluctuations. Fluoride removal and recovery were achieved through the heterogeneous crystallization of Ca²⁺ and F^- on the surface of seeds to form CaF₂. XRD and EDX Mapping results confirmed that the main ingredient of the product was calcium fluoride (CaF₂) with a purity of 89 %, which met the standard for ceramic grade fluorspar. SEM indicated that the crystal seeds transformed from fine lumpy powder to spherical particles. The fluidized bed induced crystallization technology recovered 55 % F^- as fluorspar and reduced wastewater treatment costs by 3.0 ∼ 3.5 RMB/m³, making it a more environmentally friendly and more economical technique compared with chemical precipitation.

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来源期刊

Separation and Purification Technology 工程技术-工程：化工

CiteScore

14.00

自引率

12.80%

发文量

2347

审稿时长

43 days

期刊介绍： Separation and Purification Technology is a premier journal committed to sharing innovative methods for separation and purification in chemical and environmental engineering, encompassing both homogeneous solutions and heterogeneous mixtures. Our scope includes the separation and/or purification of liquids, vapors, and gases, as well as carbon capture and separation techniques. However, it's important to note that methods solely intended for analytical purposes are not within the scope of the journal. Additionally, disciplines such as soil science, polymer science, and metallurgy fall outside the purview of Separation and Purification Technology. Join us in advancing the field of separation and purification methods for sustainable solutions in chemical and environmental engineering.