Defluoridation of Water With Activated Alumina

“…Though fluoride in minute amounts is an essential component for bones and for the formation of dental enamel in animals and humans (Grynpas et al 2000;Jackson et al 1973;Fawell et al 2006;Kumar and Moss 2008;Underwood 1997), its high concentration cause irreversible demineralization of bones and tooth tissues which is known as dental and skeletal fluorosis, damage to the brain, liver, and kidney, headache, skin rashes, bone cancer, and even death in extreme cases (Susheela 2001;Barbier et al 2010;Gazzano et al 2010;Ayoob and Gupta 2006;Chaturvedi et al 1990;Wang and Reardon 2001;Lounici et al 1997;Srimurali et al 1998;Savinelli and Black 1958;Ganvir and Das 2011;Chinoy 1991). The maximum permissible limit of fluoride in water is 1.5 mg/l as per WHO standards (WHO 1984(WHO , 2004BIS 1991).…”

Section: Introductionmentioning

confidence: 99%

Removal of fluoride from polluted waters using active carbon derived from barks of Vitex negundo plant

2015

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Background: Deleterious effects of fluoride contamination in ground waters on the health of human beings are well known and intensive research on developing de-fluoridation methods is globally pursued. Of the various methodologies, increasing interest is being envisaged in using the adsorption methods based on active carbons derived from plant material. In the present investigation, Nitric acid activated carbon derived from barks of Vitex negundo plant (NVNC) is probed for its de-fluoridation abilities. Methods: The activated carbon is characterized adopting various physicochemical methods and surface morphological studies are carried out using FT-IR and SEM-EDX techniques. The effect of various parameters such as pH, sorbent dosage, agitation time, initial concentration of fluoride, temperature, particle size and presence of foreign ions on the extraction of the fluoride is studied adopting Batch methods.The adsorption process is analyzed with Freundlich, Langmuir, Temkin and Dubinin-Radushkevich (D-R) isotherms and kinetics of adsorption is studied using pseudo first-order, pseudo second-order, Weber and Morris intraparticle diffusion, Bangham's pore diffusion and Elovich equations. The methodology developed is applied to real ground water samples.

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“…Regeneration/desorption by 0.1 N HCl and 0.1 N NaOH was not significant, 12% and 14%, respectively. Savinelli and Black (1958) and Muthukumaran (1995) also found alum solution an effective regenerant for activated alumina and activated carbon. Further, cyclic regeneration studies were conducted to find capacity loss during each cycle of regeneration and overall loss of sorption capacity.…”

Section: Desorption and Regeneration Studiesmentioning

confidence: 91%

“…To overcome the resistance of chemical bonding, chemical regeneration, i.e., desorption by chemical agents like 0.1 N HCl, 0.1 N NaOH, and 1% alum solution as investigated by earlier workers (Savinelli and Black 1958;Bulusu and Pathak 1969;Muthukumaran 1995) for desorption from and regeneration of activated alumina was investigated. It follows from the experimental results that 1% alum solution is a better regenerant yielding 70% regeneration (desorption).…”

Section: Desorption and Regeneration Studiesmentioning

confidence: 99%

“…Defluoridation by activated alumina was successfully demonstrated (Boruff 1934;Fink and Lindsay 1936;Swope and Hess 1937) and the fluoride removal capacity increases directly with fluoride concentration and inversely with pH of the water (Savinelli and Black 1958). De-greased and alkalitreated bone (Smith and Smith 1937) and bone char (Killedar and Bhargava 1988a, b) are also effective in the removal of fluoride from initial concentrations of 3.5-10.0 mg L −1 to less than 0.2 mg L −1 .…”

Section: Introductionmentioning

confidence: 96%

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Removal of Fluoride from Water by Adsorption onto Lanthanum Oxide

Rao

Kunchithapatham

2011

Water Air Soil Pollut

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Rare earth mineral based adsorbent viz. lanthanum oxide was investigated for potential application in defluoridation of drinking water for isolated and rural communities. Results of batch experiments indicated about 90% removal in 30 min from a 4 mg L −1 synthetic fluoride solution. The effects of various parameters like contact time, pH, initial concentration, and sorbent dose on sorption efficiency were investigated. Adsorption efficiency was dependent on initial fluoride concentration and the sorption process followed BET model. Variation of pH up to 9.5 has insignificant effect on sorption and beyond a pH of 9.5, the effect was drastic. Among anions investigated, carbonates exhibited high detrimental effect on fluoride adsorption while anions like bicarbonates, chlorides, and sulfates did not seriously affect the process. Adsorbent showed negligible desorption of fluoride in distilled water. Alum was more effective regenerant than HCl and NaOH.Results of cyclic regeneration with alum indicated that the sorbent could be regenerated for ten cycles without significant loss of sorption capacity. Studies with upflow fixed-bed continuous flow columns indicated the usefulness of sorbent for fluoride removal in continuous flow process.

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Defluoridation of Water With Activated Alumina

Cited by 36 publications

References 24 publications

Defluoridation of groundwater using brick powder as an adsorbent

Defluoridation of groundwater using brick powder as an adsorbent

Removal of fluoride from polluted waters using active carbon derived from barks of Vitex negundo plant

Removal of Fluoride from Water by Adsorption onto Lanthanum Oxide

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