Effect of Ca2+ ion concentration on adsorption of poly(carboxylate ether)-based (PCE) superplasticizer on mica

Wu, Bo; Chun, Byong-Wa; Gu, Le; Kuhl, Tonya L.

doi:10.1016/j.jcis.2018.05.016

Cited by 25 publications

(15 citation statements)

References 54 publications

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“…Other studies suggest that calcium-promoted adsorption of organic molecules may even drive complete disaggregation provided that the organic species diffuse into the aggregates and render clay surfaces negatively charged, or if their strong adsorption induces steric repulsion between clay platelets. 6,45,46,83,84 At high Ca 2+ concentrations, both organic molecules and clay surfaces may become positively charged because of excess calcium binding, making Ca 2+ bridges ineffective and preventing any adsorption of organic molecules onto clay surfaces altogether, as observed for polycarboxylate molecules by Wu et al 85 Thus, the degree of Ca 2+ -induced aggregation will be largely sensitive to Ca 2+ concentration, complexation strength, speciation, surface charge, and other environmental factors. Conversely, inert cations, such as Na + , may induce more severe disruption of organoclay aggregates.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Nanoscale Forces between Basal Mica Surfaces in Dicarboxylic Acid Solutions: Implications for Clay Aggregation in the Presence of Soluble Organic Acids

Dziadkowiec

Røyne

2020

Langmuir

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The stability of organomineral aggregates in soils has a key influence on nutrient cycling, erosion, and soil productivity. Both clay minerals with distinct basal and edge surfaces and organic molecules with reactive functional groups offer rich bonding environments. While clay edges often promote strong inner-sphere bonding of −COOH-laden organics, we explore typically weaker, outer-sphere bonding of such molecules onto basal planes and its significance in organomineral interactions. In this surface force apparatus study, we probed face-specific interactions of negatively charged mica basal surfaces in solutions containing carboxyl-bearing, low-molecular-weight dicarboxylic acids (DAs). Our experiments provide distance-resolved, nanometer-range measurements of forces acting between two (001) mica surfaces and simultaneously probe DA adsorption. We show that background inorganic ions display crucial importance in nanoscale forces acting between basal mica surfaces and in DA adsorption: Na+ contributes to strong repulsion and little binding of dicarboxylic anions, while small amounts of Ca2+ are sufficient to screen the basal surface charge of mica, facilitate strong adhesion, and enhance dicarboxylic anion adsorption by acting as cationic bridges. Despite reversible and weak adsorption of DAs, we resolve their multilayer binding via assembly of hydrophobic chains in the presence of Ca2+, pointing the importance of abundant, less reactive basal clay surfaces in organomineral interactions.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Nanoscale Forces between Basal Mica Surfaces in Dicarboxylic Acid Solutions: Implications for Clay Aggregation in the Presence of Soluble Organic Acids

Dziadkowiec

Røyne

2020

Langmuir

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“…The adsorption mode in cement slurries can be greatly affected by the molecular structures of SPs. [28][29] Several reports [30][31][32][33] have primarily attributed the high dispersion performance to the adsorptive capacity of SPs on the cement particles' surfaces. Figure 5 shows the adsorption capacity of the crosslinked SPs in cement samples within 120 min.…”

Section: Adsorption Amountmentioning

confidence: 99%

Effect of crosslinked polycarboxylate superplasticizers with varied structures on cement dispersion performance

Lin

Liao

et al. 2020

J of Applied Polymer Sci

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In order to investigate the effect of double bond content in the crosslinkers on the performance of superplasticizers, three different crosslinked polycarboxylate superplasticizers were synthesized herein with various respective crosslinkers. Their impacts on the fluidity, absorption, and hydration behavior of cement systems were studied. The results showed that the polymer, which was synthesized using a crosslinker with four double bonds and five/six double bonds, had higher fluidity and the highest fluidity reached up to 395 mm at W/C of 0.35. Additionally, thermogravimetric analysis and hydration heat tests showed that the crosslinked polycarboxylate superplasticizers could prolong the hydration process of cement slurries. Among these three kinds of crosslinked polycarboxylate superplasticizers, the induction period of cement slurry containing the polymer with crosslinker of four double bonds was significantly extended to facilitate the processing of the concrete. The purpose of this study is to provide strategies for studying high-performance polycarboxylate superplasticizers with novel topological structure.

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“…Comb-like polycarboxylate (PCE) superplasticizers have recently been developed and have become an integral part of modern concrete technology [6,7]. Their effects on the workability properties of fresh cement pastes (fcps), such as on the evolution of the microstructure and hydration process during the early hydration stage, still remain to be investigated [8][9][10][11]. Most studies focused on the relationship between the structure of PCEs and the fluidity of cement paste, the effect of the changing of WFT in the presence of PCEs on the fluidity of cement paste, as well as the influence of PCE on the growth rate of hydration products and the fluidity.…”

Section: Introductionmentioning

confidence: 99%

Effects of PCE on the Dispersion of Cement Particles and Initial Hydration

et al. 2021

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The effects of polycarboxylate superplasticizers (PCEs) on the dispersing properties and initial hydration of cement particles with various water-to-cement (w/c) ratios was investigated, including the water film thickness (WFT), rheology, fluidity, adsorption of PCEs, zeta potential, degree of hydration, hydration products. The experimental results demonstrate that the initial rheological and fluidity parameters were more sensitive to the PCE dosage at a lower w/c because the WFT and the zeta potential on cement particles change more significantly. Moreover, the higher adsorption amounts of the PCEs at a lower w/c lead to a stronger inhibition of the initial hydration, whilst, at the same PCE dosage, the cement pastes have a more rapid fluidity loss and quicker hydration reactions at a higher w/c due to a lower adsorption amount of the PCE on cement particles.

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Effect of Ca2+ ion concentration on adsorption of poly(carboxylate ether)-based (PCE) superplasticizer on mica

Cited by 25 publications

References 54 publications

Nanoscale Forces between Basal Mica Surfaces in Dicarboxylic Acid Solutions: Implications for Clay Aggregation in the Presence of Soluble Organic Acids

Nanoscale Forces between Basal Mica Surfaces in Dicarboxylic Acid Solutions: Implications for Clay Aggregation in the Presence of Soluble Organic Acids

Effect of crosslinked polycarboxylate superplasticizers with varied structures on cement dispersion performance

Effects of PCE on the Dispersion of Cement Particles and Initial Hydration

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