Evaluation of Fluoride Adsorption Mechanism and Capacity of Different Types of Bone Char

Benyapa Sawangjang; Phacharapol Induvesa; Aunnop Wongrueng; Chayakorn Pumas; Suraphong Wattanachira; Pharkphum Rakruam; Patiparn Punyapalakul; Satoshi Takizawa; Eakalak Khan

doi:10.3390/ijerph18136878

Evaluation of Fluoride Adsorption Mechanism and Capacity of Different Types of Bone Char

Int J Environ Res Public Health. 2021 Jun 26;18(13):6878. doi: 10.3390/ijerph18136878.

Authors

Affiliations

¹ International Postgraduate Program in Environmental and Hazardous Waste Management, Graduate School, Chulalongkorn University, Bangkok 10300, Thailand.
² Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom 73170, Thailand.
³ Department of Environmental Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand.
⁴ Research Program in Control of Hazardous Contaminants in Raw Water Resources for Water Scarcity Resilience, Center of Excellence on Hazardous Substance Management (HSM), Bangkok 10300, Thailand.
⁵ Center of Excellence in Bioresources for Agriculture, Industry and Medicine, Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
⁶ Department of Environmental Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10300, Thailand.
⁷ Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, Tokyo 113-8654, Japan.
⁸ Department of Civil and Environmental Engineering and Construction, University of Nevada, Las Vegas, NV 89154-4015, USA.

Abstract

The fluoride adsorption capacity of three types of bone char (BC), including cow BC (CBC), chicken BC (CKBC), and pig BC (PBC), was examined. At the optimum charring conditions (temperature and time), PBC had the highest hydroxyapatite (HAP) content (0.928 g-HAP/g-BC), while CBC had the highest specific surface area (103.11 m²/g-BC). CBC also had the maximum fluoride adsorption capacity (0.788 mg-F/g-HAP), suggesting that fluoride adsorption capacity depends more on the specific surface area of the BC than the HAP content. The adsorption data of CBC, CKBC, and PBC fit well with the pseudo-second-order model and the Langmuir isotherm. The maximum fluoride adsorption capacity of BC reached the maximum value when the solution had a pH of approximately 6.0. Lastly, the highest fluoride desorption occurred when the BCs were soaked in solutions with a pH higher than 11.0.

Keywords: bone char; fluorosis; hydroxyapatite.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adsorption
Animals
Bone and Bones / chemistry
Cattle
Durapatite
Female
Fluorides
Hydrogen-Ion Concentration
Kinetics
Swine
Water Pollutants, Chemical* / analysis
Water Purification*

Substances

Water Pollutants, Chemical
Durapatite
Fluorides