Removal of fluoride by hydrous manganese oxide-coated alumina: Performance and mechanism

Teng, Shao-Xiang; Wang, Shuguang; Gong, Wen-Xin; Liu, Xianwei; Gao, Baoyu

doi:10.1016/j.jhazmat.2009.02.133

Cited by 205 publications

(50 citation statements)

References 42 publications

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“…Moreover, the slopes did not pass through the origin, which indicated that the adsorption mechanism is complex and both the surface adsorption and intra-particle diffusion contribute to the rate-determining step. A similar observation was reported by Teng et al (2009) for fluoride removal by hydrous manganese oxide-coated alumina.…”

Section: Resultssupporting

confidence: 88%

Study of ZrIV-loaded Orange Waste Gel for Selenate Adsorption

Biswas

Inoue

Kawakita

et al. 2010

J. of Wat. & Envir. Tech.

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Adsorptive removal of selenate from aqueous phase using Zr IV -loaded orange waste gel was investigated. Adsorption kinetics showed that equilibrium was attained within 2 and 4 h for 12 and 23 mg/L of Se VI , respectively. A pseudo-second-order kinetic model was found to characterize the adsorption kinetics for all the initial selenium concentrations tested. Adsorption isotherms at various pH values were examined and the data fitted well with Langmuir model. The maximum sorption capacity was found to be 25 mg/g at optimum pH. The adsorption system was found to be favorable with separation factors between 0 and 1. Competitive adsorption by coexisting anions showed that chloride barely affected Se VI adsorption while phosphate and sulfate impeded Se VI adsorption. A ligand exchange mechanism was inferred for Se VI adsorption.

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Section: Resultssupporting

confidence: 88%

Study of ZrIV-loaded Orange Waste Gel for Selenate Adsorption

Biswas

Inoue

Kawakita

et al. 2010

J. of Wat. & Envir. Tech.

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“…Ca(NO 3 ) 2 and Al(NO 3 ) 3 were dissolved in 1 L deionizeddistilled water free from CO 2 at atomic ratios Al/Ca from 0 to 0.5. The total amount of Ca and Al in solution was held at 0.1 mol.…”

Section: Adsorbent Preparationmentioning

confidence: 99%

“…Excess ingestion of fluoride with high concentration can induce mottling of teeth, softening of bones, even neurological damages [2]. So, fluorosis is an important public health problem all over the world, and an appropriate concentration of fluoride (0.5-1.5 mg/L) is required to prevent dental cavities [3][4][5].…”

Section: Introductionmentioning

confidence: 99%

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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“…The concentration of fluoride was determined by ion selective electrode method (PF-1, Shanghai KangYi Technology). Total fluoride concentration was measured after mixing with total ionic strength adjustment buffer (citrate buffer solution) according to the Methods of Examination of Water and Wastewater [11]. The concentration of free fluoride was also determined by ion selective electrode method [12,13].…”

Section: Determination Of Free Fluoride and Total Fluoridementioning

confidence: 99%

“…All the reactions were strongly dependent on pH and were quick processes with time scale of 10 2 s [12,14]. During the adsorption process, fluoride was removed by ion exchange with OH − [8,11]. The acidic condition favored the release of OH − and fluoride removal.…”

Section: Comparison Of Fluoride Removal Between Coagulation and Adsormentioning

confidence: 99%

Effect of aluminum fluoride complexation on fluoride removal by coagulation

Gong¹,

Qu²,

Liu³

et al. 2012

Colloids and Surfaces A: Physicochemical and Engineering Aspect

Self Cite

128

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a b s t r a c tEffect of aluminum fluoride complexation on fluoride removal by Al salts coagulation was investigated by a series of batch experiments. Transformation of fluoride species in coagulation was studied by simultaneous determination of free fluoride and total fluoride at different pH and fluoride concentrations. Results showed that aluminum fluoride complexes dominated at low pH and high fluoride concentrations but more complexes did not represent higher fluoride removal. Comparison between coagulation with complexation and adsorption by Al(OH) 3 flocs was conducted and coagulation showed higher fluoride removal efficiency than adsorption in the pH range of 6.0-9.0. Titration test showed that Al F complexes were coprecipitated with less OH − than Al 3+ . Characterization of FTIR and XPS also indicated that flocs after complexation was different from Al(OH) 3 flocs with or without fluoride. It was concluded that a new Al F OH coprecipitate formed in coagulation and fluoride was effectively removed by the coprecipitation.

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Removal of fluoride by hydrous manganese oxide-coated alumina: Performance and mechanism

Cited by 205 publications

References 42 publications

Study of ZrIV-loaded Orange Waste Gel for Selenate Adsorption

Study of ZrIV-loaded Orange Waste Gel for Selenate Adsorption

Enhanced fluoride adsorption using Al (III) modified calcium hydroxyapatite

Effect of aluminum fluoride complexation on fluoride removal by coagulation

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