Removal of Fluoride from Aqueous Solution by Using Alum Sludge

Sujana, M.G.; Thakur, Ravindra Singh; Rao, S. Ramachandra

doi:10.1006/jcis.1998.5611

Cited by 302 publications

(178 citation statements)

References 10 publications

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“…The reduction of fluoride removal in alkaline pH range should be attributed to competition of hydroxyl ions with fluoride for adsorption sites because of similarity in fluoride and hydroxyl ions in charge and ionic radius. Similar findings have also been reported earlier [19,20].…”

Section: Adsorption Kinetics and The Effects Of Ph And Co-existing Ansupporting

confidence: 92%

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

Nie

Kong

2012

Journal of Hazardous Materials

182

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h i g h l i g h t sAl modified hydroxyapatite possessed a higher defluoridation capacity of 32.57 mg/g. Hydroxyl groups on the surface of Al-HAP was the adsorption sites for F − removal. Enhanced F − removal over Al-HAP was attributed to the modification with aluminum.a r t i c l e i n f o a b s t r a c tAluminum-modified hydroxyapatite (Al-HAP) was prepared and characterized using XRD and BET analyses. Al-HAP possessed higher defluoridation capacity (DC) of 32.57 mgF − /g than unmodified hydroxyapatite (HAP) which showed a DC of 16.38 mgF − /g. The effect of Al/Ca atomic ratio in Al-HAP, solution pH and co-existing anions was further studied. The results indicated that the adsorption data could be well described by the Langmuir isotherm model and the adsorption kinetic followed the pseudo-second-order model. The pH changes during the adsorption process suggested that the OH on the surface of Al-HAP was the adsorption sites. The more adsorption sites were formed on Al modified HAP, which possessed abundant surface hydroxyl groups, resulting in higher efficiency of F − removal. Thermodynamic parameters such as G• , H • and S • were calculated in order to understand the nature of adsorption process. The results revealed that the adsorption reaction was a spontaneous and endothermic process.

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Section: Adsorption Kinetics and The Effects Of Ph And Co-existing Ansupporting

confidence: 92%

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

Nie

Kong

2012

Journal of Hazardous Materials

182

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“…Values of resulting parameters and regression coefficients (R 2 ) are listed in Tables 4 and 5. The R 2 value for the Freundlich isotherm was 0.9990, which is higher than the values obtained from the Langmuir and Temkin isotherm models. The experimental data fit very well to this isotherm model, and indicates that fluoride adsorption occurs on heterogeneous surfaces, which is similar to the conclusion reached for nZVI [38][39][40].…”

Section: Adsorption Isothermssupporting

confidence: 84%

Response Surface Methodology for Adsorption of Fluoride Ion Using Nanoparticle of Zero Valent Iron from Aqueous Solution

Fakhri¹

2013

J Chem Eng Process Technol

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This study is removal of fluoride ion from aqueous solution by nano zero valent iron (nZVI). Effects of the factor variables (temperature, nZVI dose and pH) and their interactions on adsorption of fluoride ion were investigated by response surface methodology (RSM) based on Box-Behnken design (BBD). Optimized values of temperature, nZVI dose and pH for fluoride sorption were found as 313K, 0.5 g, and 4, respectively. The effect of initial fluoride concentration on the adsorption amount was investigated by a batch experiment. For study the fluoride removal mechanism, various adsorption isotherms such as Langmuir, Freundlich and Temkin were fitted. The results showed that the Freundlich isotherm gave high fit for fluoride adsorption. The time of adsorption reaction was rapid and subordinated pseudo-second-order kinetics. The values of thermodynamic parameters indicated that adsorption was spontaneous and endothermic in nature. The nano zero valent iron (nZVI) could be used as a potential adsorbent for fluoride ion containing aqueous solution.

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“…lead, Copper (Wu et al, 2004a) and fluoride (Sujana et al, 1998). Wu et al (2004b) also reported that sintered waterworks sludge adsorbed significant amount of toxics from a synthesised toxic wastewater and noted in particular that the sintering process can effectively prevent the release of harmful substances in the waterworks sludge to the environment.…”

Section: Adsorbent For Pollutants and Metals In Wastewatermentioning

confidence: 99%