Defluoridation performance of nano-hydroxyapatite/stilbite composite compared with bone char

Sani, Taju; Gómez‐Hortigüela, Luis; Pérez‐Pariente, Joaquín; Chebude, Yonas; Dı́az, Isabel

doi:10.1016/j.seppur.2015.11.014

Cited by 35 publications

(14 citation statements)

References 37 publications

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“…However, the fluoride removal (defluoridation) capacity of HAp has been reported to be low and efforts have been dedicated to identify new and improved methods of defluoridation. This includes preparing the HAp from biogenic sources [9,10] and also by the introduction of nanoparticles into HAp [11,12]. The underlying issue associated with the aforementioned methods of defluoridation is the influence on the pH conditions of the supernatant, which is due to the release of surface ions and/or interstitial ions from the HAp.…”

Section: Introductionmentioning

confidence: 99%

Preparation and characterization of hydroxyapatite from Achatina achatina snail shells: effect of carbonate substitution and trace elements on defluoridation of water

Asimeng

Fianko

Kaufmann

et al. 2018

Journal of Asian Ceramic Societies

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A novel hydroxyapatite [HAp: Ca 10 (PO 4) 6 (OH) 2 ] material for defluoridation was prepared from Achatina achatina (AA) snail shells using a modified chemical precipitation method. X-ray diffractometry and atomic absorption spectrometry revealed carbonate substitution as a function of stirring conditions. Stirring time was varied to control crystallite size and trace element concentrations. In addition, Infrared spectra, cyclic voltammograms, and ion exchange profiles confirmed the functional groups, the surface mass concentration and the fluoride removal efficiency, respectively. It was observed that the samples prepared after 1 hr optimal stirring times reduced fluoride concentration from 20:00 to 1:59 AE 0:06mgL À1 without affecting the overall pH conditions of the water, whereas beyond this time frame, low uptake of the fluoride ions was obtained with increasing pH conditions. It was also observed that crystallite size did not affect the removal capacity of the samples. The results demonstrated herein the possibility of using locally prepared AA shells for water purification and other environmental remediation applications.

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Section: Introductionmentioning

confidence: 99%

Preparation and characterization of hydroxyapatite from Achatina achatina snail shells: effect of carbonate substitution and trace elements on defluoridation of water

Asimeng

Fianko

Kaufmann

et al. 2018

Journal of Asian Ceramic Societies

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“…(B). The diffraction peaks of parent STI (light green) maintain their position and relative intensities upon AO loading, which once again proves that the STI structure is stable during the modification process . However, it is possible to observe a very slight shift in the peaks of STI‐AO 2:1 compared with the parent STI, probably due to shrinkage of the structure during calcination at 300°C to form AO.…”

Section: Resultsmentioning

confidence: 75%

Aluminum hydroxide supported on zeolites for fluoride removal from drinking water

Dessalegne

Zewge

Dı́az

2016

J. Chem. Technol. Biotechnol.

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BACKGROUND Problems of fluorosis are still affecting millions of people around the world including Ethiopia. Hence the need to find sustainable solutions is still worth investigating. In this study, commercial zeolite Y (ZY) and natural stilbite (STI) from Ethiopia are evaluated as support for aluminum hydroxide (AO) and studied for fluoride removal from aqueous solution. The composites (STI‐AO) and (ZY‐AO) are synthesized at different zeolite to AO ratios by modifying the procedure used for synthesizing AO, reported earlier. RESULTS The X‐ray diffraction profiles show that zeolite structures are stable during modification processes. The Si/Al ratio of composites decreases as the amount of AO is increased due to increase in Al content. The PZC of STI, initially at 2.5, increased to 9.2 in STI‐AO. Textural properties of ZY and ZY‐AO proved to block certain microporosity by the AO. Optimum conditions to reduce an initial fluoride concentration of 10 mg L−1 to below the WHO guideline value of 1.5 mg L−1 were 2 g L−1 for the 2:1 systems and 4 g L−1 for the 6:1 systems. CONCLUSION Zeolite‐AO composites have very good equilibrium fluoride adsorption capacity compared with most reported materials. Hence these materials can be considered alternative adsorbents for the removal of fluoride from drinking water. © 2016 Society of Chemical Industry

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“…where 502 is the total molecular mass of HAp, and 93 is the molecular mass of P in We used this intrinsic capacity concept to compare the performance of our zeolite composite, stilbite/nHAp or nHAST, with an adsorbent that of bone char (BC). The active phase of this BC adsorbent is hydroxyapatite (HAp), similar to that of our composite [32]. Therefore, this comparison may bring information that allows us to analyse the feasibility of implementation of the nHAST adsorbent.…”

Section: -mentioning

confidence: 94%

Environmental uses of zeolites in Ethiopia

Dı́az

2017

Catalysis Today

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In the past six years we have been intensively collaborating with the Chemistry Department of Addis Ababa University as well as Haramaya University to bust scientific knowledge related to zeolites and zeolite applications. Initially, we teamed up with geologists and government actors in the mining sectors; as a result we got access to natural zeolites from the north of the country, as well as other industrial minerals such as kaolin. In parallel we developed research activities in the use of zeolites as adsorbents and in catalytic processes related to environmental applications of necessity in Ethiopia. In the first part of this paper I will describe two examples of adsorption processes using mineral resources: one is a natural stilbite used to develop an adsorbent to remove fluoride from drinking waters; and the second one uses virgin kaolin to prepare a synthetic zeolite 4A that we used to remove chromium from tannery wastewaters. Finally, two catalytic examples will be described: in the first one we tackled the photocatalytic degradation of dyes from textile industries using Ti-modified natural and synthetic zeolites, and in the second one we used modified mordenites, both natural and synthetic, for the conversion of glucose into 5-HMF.

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Defluoridation performance of nano-hydroxyapatite/stilbite composite compared with bone char

Cited by 35 publications

References 37 publications

Preparation and characterization of hydroxyapatite from Achatina achatina snail shells: effect of carbonate substitution and trace elements on defluoridation of water

Preparation and characterization of hydroxyapatite from Achatina achatina snail shells: effect of carbonate substitution and trace elements on defluoridation of water

Aluminum hydroxide supported on zeolites for fluoride removal from drinking water

Environmental uses of zeolites in Ethiopia

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