Adsorption of polyelectrolytes onto oxides — the influence of ionic strength, molar mass, and Ca2+ ions

Vermöhlen, K; Lewandowski, H.; Narres, Hans‐Dieter; Schwuger, M. J.

doi:10.1016/s0927-7757(99)00429-x

Cited by 134 publications

(73 citation statements)

References 9 publications

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“…There are three regions on the DTG curve of alumina: (1) 20-200°C with minimum on the DTG curve at 94°C-corresponding to the exothermic desorption of hygroscopic and physically adsorbed water, (2) 200-400°C with maximum on the DTG curve at 270°C-to the endothermic desorption of chemically adsorbed water, and (3) 400-900°C with maximum 520°C-to the endothermic total dehydroxylation. As can be seen in Figs.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, the conformation of polymer chains is a result of these two competitive effects. Nevertheless, the adsorption process depends on many other parameters associated with nature of solid surface, polymer type and solution conditions [1][2][3][4][5]. The most important factors influencing adsorption process of macromolecules on the metal oxide surface are: (a) solid properties-surface charge density, its purity, size and shape of adsorbent particles; (b) polymer characteristics-its weight average molecular weight, concentration, polydispersity and degree of dissociation of polymer functional groups; (c) solution conditions-pH, ionic strength and temperature.…”

Section: Introductionmentioning

confidence: 99%

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Investigation of the alumina properties with adsorbed polyvinyl alcohol

Wiśniewska

Chibowski

Urban

et al. 2010

J Therm Anal Calorim

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The influence of solution pH on the structure of polyvinyl alcohol adsorption layer on the alumina surface was investigated. The spectrophotometry, viscosimetry, thermogravimetry, potentiometric titration and microelectrophoresis were applied in experiments. These methods enable determination of the following parameters: adsorbed amount of PVA, stability of suspension without and with polymer, thickness of its adsorption layers, changes in thermal characteristics of Al 2 O 3 surface with the adsorbed polymer, surface charge density and zeta potential of solid particles in the presence and absence of PVA, respectively. All measurements were carried out in the pH range 3-9. The obtained results indicate that pH has a great influence on the conformation of PVA chains adsorbed on the alumina surface. It is due to incomplete hydrolysis of acetate groups of polyvinyl alcohol macromolecules (degree of hydrolysis 97.5%), which dissociate with the increasing pH. Moreover, the polymer adsorption on the alumina surface causes changes in the course of thermogravimetric curves. The effect of weight loss for Al 2 O 3 -PVA systems is smaller than that of Al 2 O 3 without polymer. It is due to elimination of water molecules from the solid surface by adsorbed polymer.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Investigation of the alumina properties with adsorbed polyvinyl alcohol

Wiśniewska

Chibowski

Urban

et al. 2010

J Therm Anal Calorim

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“…An increased adsorption of polyacrylic acid on aluminium oxide in the presence of calcium ions was reported (Vermöhlen et al, 2000). The authors explained such behaviour by the ability of calcium ions to screen the negative charge of the carboxylic groups in the polymer more efficiently as compared to monovalent sodium ions, allowing the polymer to adopt a more coiled conformation on the surface thus increasing surface loading.…”

Section: Improvement Of Magnetite Wettability After Flotationmentioning

confidence: 99%

“…10 is not likely to be due to increased ionic strength upon increasing calcium concentration. According to Vermöhlen et al, polyacrylate adsorption on alumina in the presence of 3.3 mM calcium chloride was twice higher than adsorption from solution containing 10 mM NaCl, having the same ionic strength (Vermöhlen et al, 2000).…”

Section: Improvement Of Magnetite Wettability After Flotationmentioning

confidence: 99%

Interfacial properties of natural magnetite particles compared with their synthetic analogue

Potapova

Yang

Westerstrand

et al. 2012

Minerals Engineering

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a b s t r a c tUnderstanding of the interactions between iron oxides and flotation reagents is important both for flotation and agglomeration of iron ore. Model systems comprising synthetic iron oxides and pure chemical reagents are commonly applied in experimental work in order to obtain high quality data and to ease the interpretation of the empirical data. Whether the results obtained using model systems are valid for iron ore minerals and commercial reagents is a question seldom addressed in the literature. It is shown in this work that previously reported results obtained from a model system, concerning adsorption of a carboxylate surfactant and sodium metasilicate onto synthetic magnetite nanoparticles, as obtained by in situ ATR-FTIR spectroscopy and contact angle measurements, are applicable to adsorption of flotation reagents on magnetite concentrate. Additionally, the problem of restoring magnetite wetting after flotation is addressed since good wetting of a magnetite concentrate is required to produce iron ore pellets by wet agglomeration. The results from the present work indicate that the wettability of both synthetic magnetite coated with surfactant and magnetite concentrate after flotation can be improved by adsorbing a hydrophilizing agent such as silicate or polyacrylate.

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“…However, it is a complex process depending on numerous factors related to the macromolecular compound structure, nature of adsorbent surface as well as the conditions of the entire process [5][6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Impact of adsorption of poly(aspartic acid) and its copolymers with polyethylene glycol on thermal characteristic of Cr2O3

Wiśniewska

Ostolska

Sternik

2016

J Therm Anal Calorim

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The polymer structure impact on the adsorption layer conformation formed on the chromium (III) oxide surface was investigated. As adsorbates, three macromolecular compounds were tested: poly(L-aspartic acid) homopolymer and two block copolymers containing the poly(amino acid) segments as well as the poly(ethylene glycol) ones in the chain structure. Due to the ionic nature of the poly(amino acid), all measurements were carried out as a function of solution pH value. The most probable polymer chain binding mechanism was determined on the basis of the values obtained from the adsorption, potentiometric titration, turbidimetry and thermogravimetry experiments. The acquired results indicate that the solution pH has a great influence on the adsorbed macromolecule conformation. Additionally, in the case of the block copolymers, the individual structural unit affinity for the solid particles can be modified by the pH changes. Therefore, a significant difference in the mass decrement measured for the systems at pH 3 and 10 can be explained by the contribution of electrostatic forces and hydrogen bond formation to the polymer adsorption mechanism. Structure of the adsorbed polymer layer determines also the suspension stability. The solid surface charge neutralization by the macromolecules bound to the Cr 2 O 3 surface at pH 3 impairs the sample stability, whereas the presence of the extended polymer chains in the basic solution leads to the durability improvement.

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Adsorption of polyelectrolytes onto oxides — the influence of ionic strength, molar mass, and Ca2+ ions

Cited by 134 publications

References 9 publications

Investigation of the alumina properties with adsorbed polyvinyl alcohol

Investigation of the alumina properties with adsorbed polyvinyl alcohol

Interfacial properties of natural magnetite particles compared with their synthetic analogue

Impact of adsorption of poly(aspartic acid) and its copolymers with polyethylene glycol on thermal characteristic of Cr2O3

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