Attractive Forces between Charged Colloidal Particles Induced by Multivalent Ions Revealed by Confronting Aggregation and Direct Force Measurements

Sinha, Prashant; Szilágyi, István; Ruiz‐Cabello, Francisco; Maroni, Plinio; Borkovec, Michal

doi:10.1021/jz4000609

Cited by 99 publications

(157 citation statements)

References 29 publications

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“…Multivalent counterions typically strongly influence the electrostatic forces already at very minute concentrations [17][18][19][21][22][23]. These studies showed that meanfield PB theory can be used with confidence at larger separation distances, while at smaller separations of few nanometers, the experimental forces deviate from the PB description.…”

Section: Introductionmentioning

confidence: 99%

Interactions between silica particles in the presence of multivalent coions

2017

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Forces between charged silica particles in solutions of multivalent coions are measured with colloidal probe technique based on atomic force microscopy. The concentration of 1:z electrolytes is systematically varied to understand the behavior of electrostatic interactions and double-layer properties in these systems. Although the coions are multivalent the Derjaguin, Landau, Verwey, and Overbeek (DLVO) theory perfectly describes the measured force profiles. The diffuse-layer potentials and regulation properties are extracted from the forces profiles by using the DLVO theory. The dependencies of the diffuse-layer potential and regulation parameter shift to lower concentration with increasing coion valence when plotted as a function of concentration of 1:z salt. Interestingly, these profiles collapse to a master curve if plotted as a function of monovalent counterion concentration.

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Section: Introductionmentioning

confidence: 99%

Interactions between silica particles in the presence of multivalent coions

2017

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“…Sivan and coworkers [61,62] have observed an exponential short-range attraction between two silica surfaces in the presence of trivalent counterions near charge neutralization, with decay lengths of a few nanometers that were stronger than the estimated vdW forces. Further experimental work performed within the Borkovec group concentrated on a more detailed comparison with the mean-field PB calculations of the DL interactions [63][64][65][66]69]. The main conclusions stemming from these experimental endeavours elucidating the forces in the presence of multivalent counterions can be summarized as follows: The long-range separation behavior of the experimental forces can be accurately described by the PB theory, however, the effective or the renormalized surface potentials and/or charges must be used to accurately describe the data [63][64][65][66]69].…”

Section: Introductionmentioning

confidence: 99%

“…Further experimental work performed within the Borkovec group concentrated on a more detailed comparison with the mean-field PB calculations of the DL interactions [63][64][65][66]69]. The main conclusions stemming from these experimental endeavours elucidating the forces in the presence of multivalent counterions can be summarized as follows: The long-range separation behavior of the experimental forces can be accurately described by the PB theory, however, the effective or the renormalized surface potentials and/or charges must be used to accurately describe the data [63][64][65][66]69]. In many situations, these renormalized potentials are close to the surface potential values measured by electrophoretic mobility [63][64][65]69].…”

Section: Introductionmentioning

confidence: 99%

“…The main conclusions stemming from these experimental endeavours elucidating the forces in the presence of multivalent counterions can be summarized as follows: The long-range separation behavior of the experimental forces can be accurately described by the PB theory, however, the effective or the renormalized surface potentials and/or charges must be used to accurately describe the data [63][64][65][66]69]. In many situations, these renormalized potentials are close to the surface potential values measured by electrophoretic mobility [63][64][65]69]. Moreover, multivalent ions often induce charge neutralization or even charge reversal as observed from both electrophoretic mobility and direct force measurements [61, 63-65, 69, 70].…”

Section: Introductionmentioning

confidence: 99%

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Interactions between charged particles with bathing multivalent counterions: experiments vs. dressed ion theory

Kanduč

Gudarzi

Valmacco

et al. 2017

Phys. Chem. Chem. Phys.

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We compare the recent experimentally measured forces between charged colloidal particles, as well as their effective surface potentials (surface charge) in the presence of multivalent counterions in a bathing monovalent salt solution, with the predictions of the dressed ion theory of strongly charged colloidal systems. The benchmark for comparison is provided by the DLVO theory and the deviations from its predictions at small separations are taken as an indication of the additional non-DLVO attractions that can be fitted by an additional phenomenological exponential term. The parameters characterizing this non-DLVO exponential term as well as the dependencies of the effective potential on the counterion concentration and valency predicted by the dressed ion theory are well within the experimental values. This suggests that the deviations from the DLVO theory are probably caused by ion correlations as formalized within the dressed ion theory.

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“…Notwithstanding, the chemical reactions (Eqs. 1 and 2), which results in the production of AMD, bacterial oxidation is also inevitable, and occurs at pH values of less than 3.5.AMD contains different minerals and also has a high ionic movement, which results in a highly reactive tendency (Skalny et al, 2001, Niesel et al, 2005, Edwards et al, 2007, Niesel et al, 2008, Niesel et al, 2008, Firer, 2008and Sinha et al, 2013. A lot of research has been conducted on AMD and covers a diversified technological approach such as distillation, reverse osmosis, carbon nanotubes, Fenton's reagent, wet oxidation, advanced oxidation and coagulation-electro oxidation.…”

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confidence: 99%

Turbidity Removal Efficiency of Clay and a Synthetic af-PACl Polymer of Magnesium Hydroxide in AMD Treatment

Ntwampe¹

2015

ijSciences

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Abstract:In this study five 200 mL acid mine drainage (AMD) samples were treated with 5g clay (bentonite) alone or mixed with 0.1 M Al 3+ in AlCl3 and 0.1 M Mg 2+ in Mg(OH)2 polymer. The AMD samples were poured into five 500 mL glass beakers and dosed with 5 g/L of clay in a jar test, (250 rpm for 2 minutes and reduced to 100 rpm for 10 minutes) and the samples were allowed to settle for 1 hour after which the pH, conductivity, turbidity, dissolved oxygen (DO) and oxidation reduction potential (ORP) were measured. In the next step, 200 mL of the supernatant was poured into five 500 mL glass beakers and dosed with a af-PACl (acid-free polyaluminiumchloride) polymer of 0.1 M Al 3+ in AlCl3, mixed with 0.1 M Mg 2+ in Mg(OH)2, and treated in a similar manner in a jar test, settled for 1 hour, after which similar measurements were conducted, depicted as experiment (A). Another similar set of experiments was conducted, where the AMD sample was dosed with a polymer of 5 g of clay, 0.1 M Al 3+ in AlCl3 and 0.1 M Mg(OH)2 in a jar test. Similar measurements were conducted after 1 hour of settling, depicted as experiment (B). The results showed that the addition of the clay to the AMD sample as a reagent (A) or a polymeric component (B) does not affect the turbidity removal, but the rate of hydrolysis (pH changing pattern) and ORP are affected. The experimental results showed that there is a correlation between the ORP and the pH, and also showed that oxidation takes place during the destabilization-hydrolysis process. The results also showed that the conductivity plays a role during the destabilization-hydrolysis process, i.e. correlation between changing rate of the conductivity and the turbidity.Keywords: mixing, disperse, turbidity, multivalent, pH, turbidity IntroductionConventional wastewater treatment using inorganic coagulants is a common practice because aluminium, one of the reagents utilized in the process is in abundance and has also exhibited desirable effectiveness in the wastewater treatment. On the other hand, the use of polymeric flocculants over inorganic polyelectrolytes, such as poly-aluminium complexes, gives significant advantages when the water has a high concentration of suspended solids; the concentration of the polymeric flocculent is lower, the resulting sludge is more compact and there is less coagulant left in the water after treatment (Stoll, 2013). However polymeric flocculants are not always used in a rational way for optimal flocculation due to the natural fluctuations and heterogeneity of the water composition (e.g., pH, ionic composition), suspended particle concentration and corresponding physicochemical properties (e.g., sizes, shapes, surface charges). The main objective in the present study is to investigate the impact of the polymer which contains clay and Mg(OH)2 with FeCl3 on the destabilization-hydrolysis process for an AMD sample. An improved understanding of the interaction mechanisms between flocculants and the suspended material is also often necessary. Since most of the flocc...

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Attractive Forces between Charged Colloidal Particles Induced by Multivalent Ions Revealed by Confronting Aggregation and Direct Force Measurements

Cited by 99 publications

References 29 publications

Interactions between silica particles in the presence of multivalent coions

Interactions between silica particles in the presence of multivalent coions

Interactions between charged particles with bathing multivalent counterions: experiments vs. dressed ion theory

Turbidity Removal Efficiency of Clay and a Synthetic af-PACl Polymer of Magnesium Hydroxide in AMD Treatment

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