Nano Calcium Aluminum Mixed Oxide: A Novel and Effective Material for Defluoridation of Drinking Water

Abstract

In the present study Nano Calcium-Aluminium mixed oxide material (NCAMO) was synthesized by solution combustion method in 1:1, 1:2, 4:1, 3:2 molar ratios of Calcium and Aluminum nitrates as oxidizers and urea as fuel for an efficient adsorption of fluoride from drinking water.Molar composition of 1:1 ratio was found to exhibit better adsorption properties and the same Downloaded by [University of Birmingham] at 02:47 23 March 2015 A c c e p t e d M a n u s c r i p t 2 was characterized by XRD, FESEM, and FTIR. The optimized conditions for maximum adsorption capacity were achieved at pH4 with contact time of 4 hours by adding 1g/L of NCAMO to initial fluoride concentration of 8mg/L. The sorption of fluoride on NCAMO followed Langmuir isotherm model strongly suggested monolayer adsorption. The calculated equilibrium adsorption capacity 23.7 mg/g of NCAMO strongly suggests the dominance of monolayer adsorption process. The adsorption kinetics was well described by pseudo-second order equation confirming chemisorption.

Enhanced fluoride adsorption by nano crystalline γ-alumina: adsorption kinetics, isotherm modeling and thermodynamic studies

“…Moreover q e experimental and q e calculated values, for the pseudo second order model were close to each other. Hence, the pseudo-second-order model was a better descriptor of the adsorption kinetics of fluoride ion by nano sized c-alumina similar results were reported earlier (Prathibha et al 2015). These results indicated that the overall rate of the fluoride ion adsorption was most likely to be governed by the chemisorption process.…”

“…(2) Occurrences of adsorption on homogeneous sites of the adsorbent and (3) adsorbed molecules do not interact with each other. ''Langmuir isotherm is applied when adsorption is limited to monolayer formation of adsorbate on the surface of adsorbent'' (Prathibha et al 2015). The most popular linear expression of isotherm is as follows:…”

Use of CaO Loaded Mesoporous Alumina for Defluoridation of Potable Groundwater Containing Elevated Calcium Levels

“…The peaks appeared at~874 cm −1, and at~1425 cm −1 (Figure 3b-d) can be assigned to the vibration of Ca-O species [32]. The bands due to O-H stretching vibration at~1629 cm -1 [34] and O-H bending vibration at~3459 cm −1 [29] were observed in all spectra. The O-H stretching and bending vibrations depicted surface adsorbed water, which was ascribed to the formation of aluminum oxide hydroxide (AlOOH) and calcium hydroxide (CaOH 2 ) on the surface of COMA [35].…”

“…The EDX spectrum of COMA before the adsorption indicates the fact that the loading of calcium on the surface of mesoporous alumina was successful. ESEM analysis of COMA after adsorption of fluoride showed a flake-like structure (Figure 2c), which could be attributed to the formation of aluminum and calcium salts with fluoride [34]. EDX analysis confirmed the presence of aluminum (39.4%), oxygen (45,2%), calcium (6.4%), and the adsorbed fluoride (4.1%) on the surface of the COMA (Figure 2c).…”

Synthesis and Study of an Efficient Metal-Organic Framework Adsorbent (MIL-96(Al)) for Fluoride Removal from Water

“…Excessive fluoride in the human body can mineralize calcium hydroxyphosphate to calcium fluorophosphate, which causes a significant change in the fluoride-phosphorus ratio resulting in spurs, periosteal hyperplasia, osteoporosis, osteosclerosis, and bone deformation [3,4]. Long-term intake of high-fluoride food by children will result in enamel hypoplasia, tooth damage, and fluoride deposition, causing a series of deformities in the bones [5,6]. The World Health Organization (WHO) stipulates that the maximum fluoride concentration within drinking water should be 1.5 mg L -1 [7]; however, this is exceeded in some developing countries, especially in tropical countries.…”