Abstract
Excessive fluoride in potable groundwater is a serious health problem in rural areas of many developing countries. The presence of a small amount of fluoride in potable water is beneficial to human health, but a high amount (>1.5 mg/L) has adverse effects. The present study is aimed to prepare a new cost-effective adsorbent of kaolin clay that can be used as a valuable defluoridating agent. Characterization of the prepared adsorbent was carried out using DSC, FTIR, TGA, and XRD. Also, the surface area of the adsorbent was measured by BET analysis. The clay was activated with concentrated H2SO4, and the effects of various experimental parameters such as temperature (25, 40, 50, and 60°C), pH (2, 4, 6, and 8), particle size (<0.075, 0.075–0.15, and 0.15–0.30 mm), contact time (30, 60, 90, 120, and 150 min), and dose of the adsorbents (0.5, 1, 1.5, 2.0, and 2.5 g) were investigated using a batch adsorption method. The specific surface area of raw and activated clay was found to be 10.598 m2/g and 5.258 m2/g, respectively. The optimum fluoride removal by both adsorbents was obtained at pH 4, temperature 50°C, particle size 0.075 mm, and 60 min. In both adsorbents, the degree of fluoride removal was increased with a decrease in the particle size of the adsorbent and increased contact time and dosage of the adsorbent. In all parameters, adsorption by activated clay was better than raw kaolin clay for retaining fluoride. The obtained data were well fitted with Freundlich and Langmuir isotherm models.
Highlights
Nowadays, technology is playing a major role in energy, environment, and green technology environment [1,2,3,4,5,6,7,8,9,10]
Fluoride ion exists in natural waters, and it is a vital micronutrient in humans in avoiding dental caries and in facilitating the mineralization of hard tissues, if taken at a suggested range of concentration [11]. e World Health Organization (WHO) has established a guideline of 1.5 mg/L for fluoride in drinkable water [12]
Fourier-transform infrared (FTIR) spectra were found in the range of 400–4000 cm−1 to examine the major functional group present in kaolin clay and the percentage of transmittance by using JASCO model 4100 before and after adsorption for both adsorbents. e quantitative and qualitative characterization of phases, crystalline, and the number of amorphous phases present were characterized by using an X-ray diffractometer (Min 3740) by a continuous scanning axis of 2θ with a scan range of 10–80°. ermal property and mass loss of the kaolin adsorbent were analyzed by thermogravimetric analyzer (SDT Q600) with liquid nitrogen from a temperature of 20 to 1000°C
Summary
Technology is playing a major role in energy, environment, and green technology environment [1,2,3,4,5,6,7,8,9,10]. E World Health Organization (WHO) has established a guideline of 1.5 mg/L for fluoride in drinkable water [12] Higher concentration than this rate can cause fluorosis (dental and skeletal) and numerous types of neurological harm in harsh cases, such as cancer, damage kidney, liver, nervous systems, thyroids, respiratory problems, Alzheimer, and reduce pregnancy [13]. Clay is a simple sedimentary material composed mostly of fine particles of hydrous aluminium silicates and other minerals and impurities [39]. Both clay powder and fired clay are capable of sorption of fluoride as well as other pollutants from water. E present study intends to remove fluoride from groundwater using economically effective and locally available kaolinite clay adsorbents.
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