Experimental determination of the thermodynamic parameters affecting the adsorption behaviour and dispersion effectiveness of PCE superplasticizers

Plank, Johann; Sachsenhauser, Bernhard; Reese, Johanna de

doi:10.1016/j.cemconres.2009.12.002

Cited by 149 publications

(78 citation statements)

References 11 publications

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“…9). Similar phenomena have been reported for the adsorption of polycarboxylate ethers onto different surfaces, including calcium carbonate and silica fume [6,40]. In the current work, the adsorption of the copolymers onto NS would be mainly driven by the increase in entropy caused by the release of OH -anions during the substitution mechanism.…”

Section: Plain Nanosilica Dispersionssupporting

confidence: 53%

“…The length of both backbone and side chains can be variable, thus giving rise to a different effectiveness. In general, PCEs have been reported to show a comb-shaped, worm-shaped or even star-shaped molecular architecture structure, always as a function of their ratio between the main backbone and the side chain length [6]. In high alkaline pH systems (such as cement-or lime-based binders), carboxylic groups of these SPs are expected to be deprotonated as carboxylate groups.…”

Section: Introductionmentioning

confidence: 99%

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Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives

Navarro-Blasco

Perez-Nicolas

Fernández

et al. 2014

Construction and Building Materials

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Two polycarboxylate ether copolymers were assessed as superplasticizers (SPs) for hydrated lime pastes modified with two reactive compounds, nanosilica (NS) and ceramic metakaolin (MK). Characterization of the molecular structure of the SPs by Size Exclusion Chromatography, XRD, FTIR and MALDI-TOF (Matrix Assisted LaserDesorption Ionization Time-of-Flight) mass spectrometry was performed. The structures of the polymers were seen to be star-and worm-like shapes. A close relationship was found between the molecular architecture and the flowability of the pastes, being the star-shaped plasticizer the most efficient. Zeta potential assessment allowed us to elucidate a steric hindrance as the main action mechanism for these polymers. The large specific surface area of nanosilica led to a large SPs consumption as compared with metakaolin with lower surface area. However, SPs in MK-lime samples were attached favourably on the C-S-H and aluminate hydrates, so that the dispersing action was greater with respect to NS-lime suspensions.2

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Section: Plain Nanosilica Dispersionssupporting

confidence: 53%

Section: Introductionmentioning

confidence: 99%

Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives

Navarro-Blasco

Perez-Nicolas

Fernández

et al. 2014

Construction and Building Materials

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“…Plank et al [111] measured the thermodynamic parameters ΔH, ΔS and ΔG affecting the complex adsorption mechanism of PCE superplasticizers on limestone. The adsorption is driven by an enthalpic contribution caused by the electrostatic attraction, and an entropic contribution originated by the release of counter ions and water molecules into the pore solution.…”

Section: Effect Of Chemical Admixturesmentioning

confidence: 99%

Advances in understanding hydration of Portland cement

Scrivener

Juilland²,

Monteiro

2015

Cement and Concrete Research

938

340

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“…Thus, the values determined for the enthalpy only represent the ideal case of an unoccupied and homogeneous surface, i.e., they describe the forces at the beginning of the adsorption process and thus, they represent only a rough approximation [25].…”

Section: Heat Of Adsorptionmentioning

confidence: 99%

Heat of adsorption, adsorption energy and activation energy in adsorption and ion exchange systems

Inglezakis¹,

Zorpas

2012

Desalination and Water Treatment

155

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A B S T R AC TThe heat of adsorption, the adsorption energy and the activation energy are of the most important and frequently calculated parameters in adsorption and ion exchange systems. However, in many occasions these parameters are not clearly defi ned, appropriate calculated or analyzed in the related literature. A characteristic example is the use of different limits used in order to identify a process as physisorption, chemisorption or ion exchange. The present paper aims at clarifying the nature of these parameters and their interrelationship in theoretical basis and to present the paradigm of ion exchange systems involving zeolites and cations as a case study. All basic theoretical issues are presented, analyzed and discussed with the support of a large number of experimental data in order to draw secure conclusions on several critical issues. In total 46 activation energy, 32 adsorption energy and 34 heat of adsorption experimental values are collected and discussed.

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Experimental determination of the thermodynamic parameters affecting the adsorption behaviour and dispersion effectiveness of PCE superplasticizers

Cited by 149 publications

References 11 publications

Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives

Assessment of the interaction of polycarboxylate superplasticizers in hydrated lime pastes modified with nanosilica or metakaolin as pozzolanic reactives

Advances in understanding hydration of Portland cement

Heat of adsorption, adsorption energy and activation energy in adsorption and ion exchange systems

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