Mohammadtaghi Samadi; Monireh Tarlani Azar; Halimeh Almasi; Samaneh Shanehsaz; Roya Harati
Volume 22, Issue 4 , September and October 2015, , Pages 699-707
Abstract
Background & Objectives: Fluoride concentration in drinking water is one of the effective parameters in human health, and the majority of the body's requirement for fluoride is supplied through drinking water. Fluoride in low concentration is essential for human but in high concentration is very ...
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Background & Objectives: Fluoride concentration in drinking water is one of the effective parameters in human health, and the majority of the body's requirement for fluoride is supplied through drinking water. Fluoride in low concentration is essential for human but in high concentration is very hazardous for human health. In the present study, the efficiency of modified-clay and lime-marl as adsorbents was investigated for the elimination of fluoride from aqueous solution. Material & Methods: This experimental study was conducted at the Hamedan University of Medical Sciences in 2014. The effects of several parameters such as pH (4, 7 and 10), the adsorbent dosage (1, 5 and 10 g/L), initial concentration of fluoride (5, 10 and 15 mg/L), contact time (15-120 min) on the removal have been studied. Also, the structural characteristics of both adsorbents were evaluated using X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR). Results: According to the results obtained, the removal efficiency of fluoride, at concentration 10 mg/L and the approximate time of 60 min, in the case of clay-modified adsorbent is 95.23% and in the case of lime-marl adsorbent is about 28.71%. Langmuir and Freundlich coefficients were determined in the optimum conditions, and the adsorption isotherm could be described by the Langmuir model(R2=0.9907). Kinetic study showed that the equilibrium time was 60 min. The adsorption kinetics fitted well with the Ho pseudo second-order kinetic model (R2=0.994). Conclusion: According to our finding, it is proposed that the adsorption process of fluoride by clay-modified is very efficient and economics for fluoride removal from aqueous solution.