The removal of zinc from solutions by foam separation, II. Precipitate flotation of zinc hydroxide

Jurkiewicz, Kazimierz

doi:10.1016/0301-7516(90)90002-g

Cited by 7 publications

(3 citation statements)

References 13 publications

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“…Furthermore, the zinc surface is predicted to be covered in zinc hydr (oxide), 31,33 for which the isoelectric point is greater than pH 7. [37][38][39] It thus follows that the surface is positively charged at this pH and that anionic L-tryptophan adsorbs directly onto the zinc surface, whilst the cationic form of L-tryptophan may adsorb via halide ions 40 It has previously been found that halide ions adsorb on the metal surface by creating oriented dipoles and consequently increase the adsorption of the organic cations on the dipoles. 41 Due to the large dipole moment of a water molecule electrostatic bonding may not be strong enough, limiting inhibition efficiency 36 The similarity of the potentiodynamic curves obtained in the absence and the presence of L-tryptophan is thus concurrent with findings regarding the potential dependent nature of L-tryptophan adsorption on metals.…”

Section: Discussionmentioning

confidence: 97%

“…At pH 7 L-tryptophan exists in its zwitter ionic form. Furthermore, the zinc surface is predicted to be covered in zinc hydr (oxide) 31,33 , for which the isoelectric point is greater than pH 7 [37][38][39] . It thus follows that the surface is positively charged at this pH and that anionic L-tryptophan adsorbs directly onto the zinc surface, whilst the cationic form of L-tryptophan may adsorb via halide ions 40 .…”

Section: Inhibition Via An Adsorption Mechanism;mentioning

confidence: 99%

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The Role of pH on the Inhibition of Aqueous Zinc Corrosion by L-tryptophan

Wint¹,

Sullivan²,

Penney³

2017

J. Electrochem. Soc.

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A combination of in situ Scanning Vibrating Electrode Technique (SVET), and time lapse photography were used to investigate the influence of the amino acid, Ltryptophan, on the localized corrosion occurring on unpolarized zinc (Zn) samples immersed in a 0.17 mol.L-1 aqueous sodium chloride electrolyte. The addition of 1 x 10-2 mol.L-1 of L-tryptophan was found to have a significant effect on the corrosion rate for all pH values tested. At both pH 2 and pH 7, primary protection was suggested to occur as a result of adsorption due to electrostatic interactions. A secondary mechanism, whereby an insoluble complex is formed between Zn (II) ions and anionic L-tryptophan, was also proposed to occur at areas of localized high pH. At pH 2 the additions resulted in an 88 % decrease in mass loss, as measured by gravimetric mass loss results and SVET, demonstrating the effectiveness of L-tryptophan inhibitors for this material.

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Section: Discussionmentioning

confidence: 97%

Section: Inhibition Via An Adsorption Mechanism;mentioning

confidence: 99%

The Role of pH on the Inhibition of Aqueous Zinc Corrosion by L-tryptophan

Wint¹,

Sullivan²,

Penney³

2017

J. Electrochem. Soc.

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“…For example, Shakir et al [25] obtained removal ratio of Al(III) equal to about 0.97 for pH = 6.0 when c SDS = 0.4 mmol dm −3 and c 0(Al) = 20 mmol dm −3 . Jurkiewicz [28] obtained a removal ratio of Zn(II) equal to about 0.92 for pH = 9.0 when c SDS = 0.2 mmol dm −3 and c 0(Zn) = 1 mmol dm −3 .…”

Section: Effect Of Ph On the Flotation Rate Constantmentioning

confidence: 97%

Simultaneous Removal of Al, Cu and Zn Ions from Aqueous Solutions Using Ion and Precipitate Flotation Methods

Rybarczyk

Kawalec-Pietrenko²

2021

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This paper presents the results of investigations concerning the simultaneous removal of Al(III), Cu(II), and Zn(II) from dilute aqueous solutions using ion and precipitate flotation methods. The effects of initial solution pH, surface active substance concentration, and the gas velocity on the flotations’ efficiency and course are studied. Experimental results are discussed in terms of physicochemical aspects related to aqueous solutions of metal salts. The results indicate that satisfying simultaneous flotations of aluminum, copper and zinc species are observed if the pH value ranges between 7.0 and 9.0. It was found that an increase in collector concentration results in a decrease in the flotation rate constants. An increase in the gas velocity results in an increase in the ion and precipitate flotation rates.

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