EDTA impact on Cd2+ migration in apatite–water system

Tõnsuaadu, Kaia; Viipsi, Karin; Trikkel, Andres

doi:10.1016/j.jhazmat.2007.10.051

Cited by 23 publications

(11 citation statements)

References 26 publications

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“…As a result of the reaction with apatite, the pH value of the LaCl 3 0.02 M solution decreased from 5.35 to 4.8 and 3.7 in presence of HAp or FAp, respectively. This is typical for a cation-binding reaction with apatite [29][30][31] and related to the apatite surface properties. Apatite has been shown to form surface layers that differ compositionally from the bulk.…”

Section: Chemical Compositionsmentioning

confidence: 92%

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Sorption of tartrate ions to lanthanum (III)-modified calcium fluor- and hydroxyapatite

Aissa

Debbabi

Gruselle

et al. 2009

Journal of Colloid and Interface Science

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Section: Chemical Compositionsmentioning

confidence: 92%

“…For the starting HAp and FAp, the isotropic 31 [32]. The main characteristic of the 31 P NMR spectra of the La-modified apatites was the presence of a major isotropic signal at +2.75 ppm, indicating that the apatite structure was unmodified (Fig.…”

Section: Solid-state 31 P Mas Nmr Spectramentioning

confidence: 97%

Sorption of tartrate ions to lanthanum (III)-modified calcium fluor- and hydroxyapatite

Aissa

Debbabi

Gruselle

et al. 2009

Journal of Colloid and Interface Science

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“…Ca-HA is known as a versatile material for different domains of applications, in particular environmental purposes, thank to its intrinsic physico-chemical properties: high specific surface area, very low solubility in water, high thermal stability, high ionic exchange capacity for several cations and anions [5,6]. However, most of developments of Ca-HA based materials in environmental field are limited to the liquid phase for the removal of fluoride [7,8]; organic pollutants [9][10][11][12]; metals and heavy metals [13][14][15] etc.…”

Section: Introductionmentioning

confidence: 99%

Highly Porous Calcium Hydroxyapatite-based Composites for Air Pollution Control

Kemiha

Minh

Lyczko

et al. 2014

Procedia Engineering

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The control of emission gas from incinerators appears as a key issue for the improvement of the incineration technology. In this paper, we developed new sorbent materials based on calcium hydroxyapatite (Ca-HA) matrix. Using gelatine and bio-glass as porous and structural agents, which are largely available and have reasonable costs, powder of Ca-HA could be easily formulated into desired morphologies. As an example, a Ca-HA based accumulator having good porosity and mechanical stability was obtained by mixing Ca-HA powder with gelatine, bio-glass and water, followed by molding, then calcination steps. This accumulator showed an interesting capacity for the collection and tracing of Cd used as single model heavy metal in gas phase.

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“…However, the reports on the interaction of calcium and magnesium phosphates with aqueous solutions of chelating agents are reduced to the study of the interaction of hydroxyapatite with EDTA [7,8].…”

mentioning

confidence: 99%

“…The content of Ca 2+ in the sample solutions was 0.05, that of chelating agents was 0.001 M. When conducting experiments using chelating agents the prepared mixture of CaCl 2 with an addition of EDTA or OEDP was adjusted to pH 5.0 with solutions of HCl or KOH, and then aged for 1 day, afterwards, if necessary, pH was further adjusted. The selection of pH 5.0 of initial solutions was due to the creation of suitable conditions for the preferential formation of the metal−ligand complexes and to minimize the formation of hydroxo complexes [8].…”

mentioning

confidence: 99%

Stability of calcium and magnesium phosphate sorbents in solution of calcium chloride and complexing agents

et al. 2015

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The study of the stability and physicochemical transformations of calcium and magnesium phosphate sorbents in a solution of calcium chloride and complexing agents: disodium salt of ethylenediaminetetraacetic acid and oxyethylidenediphosphonic acid established that calcium phosphates undergo no signifi cant changes in aqueous systems under study, while magnesium phosphates (trimagnesium phosphate and magnesium hydrogenphosphate) are converted into calcium phosphates in solutions of CaCl 2 , therewith the introduction of ethylenediaminetetraacetic acid (EDTA) into the solution of CaCl 2 has no signifi cant effect on the magnesium phosphate conversion process, and introduction of oxyethylidene diphosphonic acid (OEDP) inhibits crystallization of calcium phosphate formed. Observed conversions should be considered when using magnesium and calcium phosphates as sorbents.Sorbents obtained earlier based on calcium and magnesium phosphates have shown high effi ciency in purifi cation of aqueous solutions from various metal ions (Zn 2+ , Cu 2+ , Pb 2+ , Cd 2+ , Ni 2+ , Co 2+ , etc.), including ions of stable and radioactive strontium [1,2]. An effi ciency of sorption purifi cation is largely determined by both the nature of the sorbent and sorption process conditions (composition of a solution, a ratio of the solution volume to weight of the sorbent, pH, etc.) [3−5]. Researching the sorption of ions of various metals was performed by means of model solutions in the absence of any other impurities, while the actual wastewater and liquid radioactive waste contain substantial quantities of dissolved calcium salts and organic compounds: surfactants and chelating agents [usually ethylenediaminetetraacetic acid (EDTA), oxyethylidenediphosphonic (OEDP) acid [6].Given that phosphate sorbents contain calcium and magnesium cations, which form stable complexes with EDTA and OEDP a possible interaction in systems chelating agent−sorbent can be propose, and in the solutions of CaCl 2 calcium and magnesium phosphates may undergo chemical and phase transformations. However, the reports on the interaction of calcium and magnesium phosphates with aqueous solutions of chelating agents are reduced to the study of the interaction of hydroxyapatite with EDTA [7,8].In the study researching the stability, chemical and physical processes occurring in the interaction of calcium and magnesium phosphate sorbents with calcium ions and chelating agents (EDTA and OEDP) was performed for effective practical use of calcium and magnesium phosphates in the sorption purifi cation of real wastewater and liquid radioactive waste. EXPERIMENTALСalcium and magnesium synthetic phosphates of different composition were used as objects of study: acidic CaNPO 4 (calcium hydrogen phosphate, CHP) and MgHPO 4 ·3H 2 O (magnesium hydrogen phosphate trihydrate, MHPTH); medium Ca 3 (PO 4 ) 2 ·2H 2 O (tricalcium phosphate dihydrate, TCPDH) and Mg 3 (PO 4 ) 2 ·10H 2 O (trimagnesium phosphate decahydrate, TMPDH) with a small admixture of MgNH 4 PO 4 ·H 2 O and Mg 2 PO 4 OH·4H ...

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EDTA impact on Cd2+ migration in apatite–water system

Cited by 23 publications

References 26 publications

Sorption of tartrate ions to lanthanum (III)-modified calcium fluor- and hydroxyapatite

Sorption of tartrate ions to lanthanum (III)-modified calcium fluor- and hydroxyapatite

Highly Porous Calcium Hydroxyapatite-based Composites for Air Pollution Control

Stability of calcium and magnesium phosphate sorbents in solution of calcium chloride and complexing agents

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