Complexes of cadmium with phosphoric acid

Elyayaoui, A.; Boulhassa, S.; Guillaumont, R.

doi:10.1007/bf02040310

Cited by 11 publications

(3 citation statements)

References 15 publications

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“…According to the results, the overall reduction efficiency of iron was 99.63%, indicating that iron phosphate complexes of Fe(HPO 4 ) + and Fe(H 2 PO 4 ) 2+ are more predominant than Fe(H 2 PO 4 ) − 4 . Moreover, based on the obtained results, we also expected that cadmium may exist in its free aquo ionic form within Cd(H 2 PO 4 ) + [32]. In addition, G. Senanayake et al (2016) reported that neodymium (Nd) forms complexes of Nd(HPO 4 ) − 2 , Nd(H 2 PO 4 ) 2+ and Nd(HPO 4 ) + in phosphoric acid [33][34][35].…”

Section: Purification Of Phosphoric Acidmentioning

confidence: 65%

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

et al. 2022

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The utilization of phosphoric acid in various sectors, e.g., food industry, is controlled by the authorized concentration limit of impurities. However, industrial phosphoric acid is contaminated with undesirable impurities (such as F, Al, Fe, Mg, etc.). Herein, this study aimed to evaluate the efficiency of the membrane purification process of pretreated industrial phosphoric acid using a premodified nanofiltration membrane. We demonstrated that the prior pretreatment steps for industrial phosphoric acid allowed the elimination of sulfate, fluorine and arsenic. Further purification of the obtained pretreated phosphoric acid using membrane cells reduced the concentrations of Cd, Al, Fe and rare earth elements by 94.81, 99.30, 99.63 and 96.67%, respectively. The membrane is functionalized by a deposit of a high molecular weight polycationic polymer of polyethyleneimines in order to produce a highly charged membrane surface to enhance the separation efficiency, selectivity and stability of the membrane. We found that the purification process relies on electrostatic repulsion between the functionalized membrane and highly charged ions, and the reduction rate of metals is a cation charge-dependent parameter. The laboratory and industrial pilot scale results showed that this process allows the production of food-grade phosphoric acid.

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Section: Purification Of Phosphoric Acidmentioning

confidence: 65%

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

et al. 2022

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“…Hietanen's data, together with new experimental results, were analyzed by Iuliano and Porto [27] who proposed the formation of Cd(H 2 PO 4 ) + and Cd(H 2 PO 4 ) 2 . Both complexes were also postulated by Elyayaoui et al [28] from distribution experiments.…”

Section: List Of Symbolsmentioning

confidence: 73%

Correlation of the Extraction Constant Values of Zn2+ and Cd2+ from Phosphoric Acid Media by Bis(2,4,4-trimethylpentyl)dithiophosphinic Acid Dissolved in Toluene

2012

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Values of the extraction constants of Zn 2+ and Cd 2+ from aqueous phosphoric acid solutions (0.36 to 7.31 mol·L −1 ) by Cyanex 301 in toluene, involving formation of the complexes ZnR 2 and CdR 2 with R being bis(2,4,4-trimethylpentyl)dithiophosphinate, have been correlated at T = 298 K as a function of the ionic strength. For this purpose the activity coefficients of all of the aqueous species have been calculated taking into account both the protolytic equilibria of concentrated phosphoric acid and complexation reactions between the cations and the phosphoric acid species. Good correlations have been obtained for the extraction constant values with the ionic strength, provided the release of water molecules during the extraction processes is considered. Finally, extraction constant values are reported at infinite dilution.

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“…He used Cyanex 93 which contains 93% wt TOPO. Elyayaoui [6] used 109 Cd in laboratory phosphoric acid media with concentrations less than 4 molL −1 and at pH < 2.7 which are close to the real commercial phosphoric acid. He used di (2-ethyl hexyl) phosphoric acid (DEHPA) solvent in benzene with 2 molL −1 concentration.…”

Section: Introductionmentioning

confidence: 98%

Extraction of cadmium from phosphoric acid by trioctylphosphine oxide/kerosene solvent using factorial design

Kherfan

2011

Per. Pol. Chem. Eng.

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Cadmium is present in all types of phosphates in concentrations ranging from 1 -90 ppm. During digestion of phosphates by concentrated sulfuric acid to produce phosphoric acid by the wet method 70-80% wt of cadmium is transferred to the phosphoric acid while 20-30% wt remains in solid phosphogypsum. Cadmium is then transferred from the phosphoric acid to the fertilizers. Most environmental regulations try to reduce the percentage of cadmium in the fertilizers. Several studies were carried out to reduce the concentration of cadmium in phosphoric acid. Some used ion-exchange techniques. Others used liquid-liquid extraction by alkaline solvents such as trioctylamine (TOA). Several investigators used commercial phosphoorganic solvents such as Cyanex 302 and Cyanex 93. This paper studies the extraction of cadmium from phosphoric acid by trioctylphosphine oxide (TOPO) solvent in kerosene. The extraction was enhanced by the presence of Cl − in the solution. The temperature had a negative effect on the extraction. Increasing the concentration of cadmium while keeping chloride ion concentration constant decreased the extraction. The extraction was increased by increasing the concentration of the phosphoric acid.

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Complexes of cadmium with phosphoric acid

Cited by 11 publications

References 15 publications

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

Wet Process Phosphoric Acid Purification Using Functionalized Organic Nanofiltration Membrane

Correlation of the Extraction Constant Values of Zn2+ and Cd2+ from Phosphoric Acid Media by Bis(2,4,4-trimethylpentyl)dithiophosphinic Acid Dissolved in Toluene

Extraction of cadmium from phosphoric acid by trioctylphosphine oxide/kerosene solvent using factorial design

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