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

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

doi:10.3390/ijerph18136878

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.

Highlights

IntroductionA substantial percentage of the population around the world, especially in South and Southeast Asia, perceive groundwater to be of better quality than surface water (in terms of microbial contamination), and prefer it as a source of drinking water [1,2,3]
A substantial percentage of the population around the world, especially in South and Southeast Asia, perceive groundwater to be of better quality than surface water, and prefer it as a source of drinking water [1,2,3]
The results are shown in chicken BC (CKBC) at 0.85 g-HAP/g-bone char (BC)

Summary

Introduction

A substantial percentage of the population around the world, especially in South and Southeast Asia, perceive groundwater to be of better quality than surface water (in terms of microbial contamination), and prefer it as a source of drinking water [1,2,3]. Groundwater may be contaminated by excessive concentrations of arsenic and fluoride [4,5]. Fluoride contamination in groundwater originates mainly from the dissolution of natural minerals in rocks [6]. The effects of fluoride on human health depend on its concentration in the drinking water ingested by individuals. Fluoride is effective in preventing tooth decay, especially among children, when the concentrations are less than 0.5 mg/L [7,8]. Higher fluoride concentrations are known worldwide to cause serious health problems, such as dental and skeletal fluorosis. The World Health Organization (WHO) set the threshold fluoride concentration in drinking water at 1.5 mg/L [12]

Methods

Discussion

Conclusion