Fluoride removal performance of highly porous activated alumina

Fluoride removal performance of highly porous activated alumina

Publication Year:
Yu, Chenglong; Liu, Lin; Wang, Xiaodong; Fu, Jiarui; Wu, Yinan; Feng, Chen; Wu, Yu; Shen, Jun
Resource Type:
Journal Article
Activated alumina (AA) is promising for fluoride removal but is limited by conventional production methods. This study synthesized porous AA using a sol–gel method, supercritical drying, and calcination. The enhanced AA demonstrated higher fluoride adsorption capacities, due to its increased porosity and surface area, outperforming traditionally produced AA. Adsorption processes involved both chemical and physical mechanisms.
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Resource Information


Activated alumina (AA) with metastable crystal phase and porous structure has shown great potential for fluoride ion removal. Conventional AA is obtained by direct calcination, which limits its fluoride adsorption ability due to the low surface area and limited active sites. In this work, a highly porous AA was synthesized by a sol–gel method, followed with supercritical drying (including ethanol supercritical drying and carbon dioxide supercritical drying) and calcination. The fluoride ion adsorption properties of AA were studied at different concentrations of fluoride in solution. The Langmuir model, Freundlich model, pseudo-first-order model and pseudo-second-order model were used to describe the adsorption process. The results show that the resulting AAs possess a high porosity and a high specific surface area (up to 660 m2/g). The fluoride adsorption capacity of AA increases with the increase of specific surface area and porosity (up to 119.2 mg/g), which is much higher than that of AA prepared by the traditional method (direct calcination). Moreover, all the fitted correlation coefficients of the four models exceed 90%, indicating both chemical and physical adsorption in AA.

Resource Type

Journal Article

Publication Year



Yu, Chenglong; Liu, Lin; Wang, Xiaodong; Fu, Jiarui; Wu, Yinan; Feng, Chen; Wu, Yu; Shen, Jun



Specific Contaminants

Other Chemicals, Fluoride

University Affiliation

Tongji University

Business Connect Takeaways

The study investigates the mechanism of fluoride removal by aluminum chloride (AlCl3) and aluminum (Al13) coagulants in water treatment processes.
The results suggest that the defluorination efficiency of AlCl3 and Al13 is influenced by the pH, initial fluoride concentration, and coagulant dosage.
The study provides insights into the role of aluminum speciation in defluorination and highlights the importance of optimizing the coagulation process to improve the removal of fluoride from water.

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