Defluoridation of water via doping of polyanilines

Karthikeyan, M.; Satheeshkumar, K.; Elango, K. P.

doi:10.1016/j.jhazmat.2008.07.057

Cited by 54 publications

(32 citation statements)

References 27 publications

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“…Though the electronic attraction and chemical adsorption were involved in the adsorption for all aluminas, different surface properties and adsorption behaviors between acidic alumina and basic alumina implied the difference in the mechanism of fluoride removal. Meanwhile, besides the exchange between OH − and fluoride, exchange of Cl − and fluoride was also reported when using an organic adsorbent treated by HCl [39,40]. Due to the difference in the ion exchange sites between acidic alumina and basic alumina [26], we predicted that their ion exchange processes were also different and the result was shown in Fig.…”

Section: Discussionmentioning

confidence: 76%

Adsorption of fluoride onto different types of aluminas

Gong

Liu

et al. 2012

Chemical Engineering Journal

121

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a b s t r a c tIn this study, five aluminas were synthesized at different pH and calcination temperatures, and the surface properties and defluoridation performance of aluminas were investigated. Characterization of XRD showed that five aluminas were poorly crystallized with different phases and their anion exchange capacity and the point of zero charge varied with the species of aluminas. The batch experiments (thermodynamics, kinetics and the effect of pH) were conducted to evaluate the fluoride adsorption behavior of different aluminas. For all aluminas, both Langmiur and Freundlich models fitted the adsorption isotherms well and the calculation of thermodynamics showed that adsorption was spontaneous and endothermic; the kinetics was well described by the pseudo-second-order model and the weak acidic pH favored the fluoride adsorption. Acidity/basicity of alumina exhibited significant effect on the behaviors of adsorption and the process of ion exchange in fluoride removal. Acidic alumina exhibited higher ion exchange capacity, more positively charged surface, and better defluoridation performance (higher adsorption capacity and quicker removal of fluoride) than basic alumina. Acidic alumina also showed higher efficiency when treating natural ground water without pH adjustment. The difference in the adsorption properties was ascribed to the different exchange sites and the different behaviors of anion exchange. In the case of acidic alumina, more Cl − was exchanged with fluoride and the adsorption/release of OH − was dependent on the initial fluoride concentration. For basic alumina most of exchange sites were provided by OH − and fluoride was removed through the exchange between fluoride and OH − .

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Section: Discussionmentioning

confidence: 76%

Adsorption of fluoride onto different types of aluminas

Gong

Liu

et al. 2012

Chemical Engineering Journal

121

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“…In the EDAX spectrum, the elements like sodium, magnesium, silica, sulfur, chloride, potassium, calcium, iron and bromine were present along with carbon and oxygen. EDAX proves the presence of fluoride ion after adsorption which confirms the fluoride sorption (Karthikeyan et al 2009). …”

Section: Sem and Edax Analysismentioning

confidence: 55%

Fluoride removal study using pyrolyzed Delonix regia pod, an unconventional adsorbent

Ajisha¹,

Rajagopal²

2014

Int. J. Environ. Sci. Technol.

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Applicability of the new material pyrolyzed Delonix regia pod carbon for the removal of excess fluoride ions from the water that harm the human and the environment was studied. The adsorbent was characterized both physically and chemically. Surface chemistry characterization was done with pH-drift method. Batch adsorption studies were carried out for the effect of pH, dosage, contact time, initial fluoride concentration, temperature and interfering co-ions. The physicochemical properties and textural characters were analyzed. Equilibrium data were studied using Freundlich, Langmuir, Temkin and Dubinin-Radushkevich models, in which Freundlich isotherm was considered to be the best fit for the adsorbent. The sorption nature was studied using thermodynamic parameters which showed spontaneous, irreversible, stable and endothermic. The adsorption kinetics follows pseudo-second order. The mechanism of adsorption was determined from intraparticle diffusion model. Boyd plot showed that the adsorption of fluoride on the carbon was mainly governed by particle diffusion.

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“…During recent years, several technologies have been applied to remove fluoride from drinking water, such as adsorption, chemical treatment, ion exchange, membrane separation, electrolytic defluoridation and electro dialysis [2][3][4][5][6][7][8], etc. Most of the methods have distinct limitations and disadvantages, while adsorption is the most widely used method because it is simple, economical and efficient for producing high quality water.…”

Section: Introductionmentioning

confidence: 99%

Removal of F from Water Using PPyCl/ATP Composites

Chen¹,

Li²,

Xu³

2017

Proceedings of the 2016 4th International Conference on Renewable Energy and Environmental Technology (ICREET 2016)

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Abstract. Conducting polypyrrole(PPy) was found to possess potential efficiency to remove F − from aqueous solutions. In this study doped with Cl − PPyCl/ATP composites were prepared via in-situ polymerization and employed as adsorbent to remove from aqueous solutions. The ability of the adsorbent to remove F − from aqueous solution was demonstrated in a batch sorption mode.External factors such as initial concentration of F − , contact time, adsorbent dosage and pH value of solution how to influence the adsorption efficiency of composites were investigated. The results showed that the adsorption efficiency is strongly pH, initial concentration and adsorbent dose dependent. Experiment data fitted well to the Langmuir isotherm model. The adsorption kinetics is described by the pseudo-second-order model. Meanwhile, the adsorption may proceed by an ion exchange mechanism between Cl − and F − .

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Defluoridation of water via doping of polyanilines

Cited by 54 publications

References 27 publications

Adsorption of fluoride onto different types of aluminas

Adsorption of fluoride onto different types of aluminas

Fluoride removal study using pyrolyzed Delonix regia pod, an unconventional adsorbent

Removal of F from Water Using PPyCl/ATP Composites

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