Flocculation of kaolin particles by two typical polyelectrolytes: A comparative study on the kinetics and floc structures

Yu, Jianfeng; Wang, Dongsheng; Ge, Xiaopeng; Yan, Mingquan; Yang, Min

doi:10.1016/j.colsurfa.2006.05.040

Cited by 111 publications

(60 citation statements)

References 40 publications

(77 reference statements)

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“…When low molecular weight polymers tend to adsorb and neutralize the opposite charges on the particles, charge neutralization becomes a major mechanism in polymer-particle interactions. Yu et al (2006) investigated the flocculation of kaolin particles by polyelectrolytes and found that the floc structures via charge neutralization are more compact. Additionally, electrostatic patch model applies when the particles have a fairly low density of immobile surface charges and the adsorbing polymers have high charge density.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Zhu

et al. 2009

International Journal of Mineral Processing

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a b s t r a c t a r t i c l e i n f oAlthough the synthetic organic polymers have been widely applied as flocculant aids to improve solid-liquid separation efficiency, it is not very clear how the charge type and molecular weight of the polymers influence the characteristics of flocs. In this paper, floc characteristics, such as floc size, density, structure, strength and reversibility were investigated in details in terms of their response to the polyacrylamide (PAM) with different charge types and molecular weights. Laser light scattering, image analysis and settling technology were employed simultaneously. The results showed that floc size induced by anionic PAM with medium molecular weight (A130) and ultra high molecular weight (A115) was 419 µm and 438 µm respectively, correspondingly, floc size induced by cationic PAM with medium molecular weight (C448) and very high molecular weight (C498) was 731 µm and 796 µm. Meanwhile, floc fractal dimension was inversely proportional to polymer molecular weight and the values were between 1.91 and 2.40. In addition, floc density was affected by molecular weight of anionic PAM more dramatically than that of cationic PAM. For a given floc size, the density increased with molecular weight. Furthermore, flocs formed by cationic PAM showed much greater shear-resistant ability and reversibility than anionic PAM. Nevertheless, the poor reversibility of the flocs formed by high molecular weight was also observed. An explanation for the resultant floc characteristics was offered in terms of flocculation mechanisms.

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Section: Introductionmentioning

confidence: 99%

“…Knowledge of floc characteristics is essential for the optimization of flocculation process (Glover et al, 2001;Ray and Hogg, 1987;Yukselen and Gregory, 2004;Yu et al, 2006). Nasser and James (2006) have investigated the effect of charge density and molecular weight of PAM on the flocculation and settling behaviors of kaolin suspensions.…”

Section: Introductionmentioning

confidence: 99%

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Zhu

et al. 2009

International Journal of Mineral Processing

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“…Mass fractal dimension was measured using SmallAngle Light Scattering as described in the literatures before [18,19]. This method involves the measurement of light intensity I as a function of the scatter vector Q.…”

Section: Methodsmentioning

confidence: 99%

“…D f values in different coagulation times were calculated according to the method reported by Yu et al [19]. The D f values in different coagulation times are shown in Table 1.…”

Section: Particle Size and Structure Of Flocsmentioning

confidence: 99%

Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS)

Li¹,

Wang

et al. 2012

Desalination and Water Treatment

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(2012) Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS), Desalination and Water Treatment, 49:1-3, 157-164, DOI: 10.1080/19443994.2012.708222 To link to this article: http://dx.doi.org/10. 1080/19443994.2012.708222 PLEASE SCROLL DOWN FOR ARTICLETaylor & Francis makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representations or warranties whatsoever as to the accuracy, completeness, or suitability for any purpose of the Content. Any opinions and views expressed in this publication are the opinions and views of the authors, and are not the views of or endorsed by Taylor & Francis. The accuracy of the Content should not be relied upon and should be independently verified with primary sources of information. Taylor and Francis shall not be liable for any losses, actions, claims, proceedings, demands, costs, expenses, damages, and other liabilities whatsoever or howsoever caused arising directly or indirectly in connection with, in relation to or arising out of the use of the Content. This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sub-licensing, systematic supply, or distribution in any form to anyone is expressly forbidden. Ferrihydrite is effective in arsenic removal because of the considerable amount of active hydroxyl groups. Solid-liquid separation of the arsenic adsorbed ferrihydrite from aqueous solution is important for the arsenic treatment technology. Coagulation is a promising process for ferrihydrite separation. Effects of different coagulants on arsenic adsorbed ferrihydrite settlement were investigated. Surface charge significantly decreased after arsenic was adsorbed on ferrihydrite. Turbidity, iron and arsenic removal efficiencies were used to characterize the ferrihydrite settling process. Turbidity removal efficiency with polyferric sulfate (PFS) added was 98.2% when pH was 5.0. Meanwhile, the turbidity removal rate with polyaluminium chloride (PAC) added was 96.3-97.3% when the pH of colloidal suspensions was 7.0-9.0. Arsenic or iron removal rate after 30 min settling was improved from about 40 to 80% with coagulants added. The mean size of flocs after coagulation process was 61.8 lm after PFS was added, or 71.6 lm after PAC was added when the pH was 6.5. The floc structure of ferrihydrite became more compact and stable with PAC or PFS added.

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“…Furthermore, it was shown that the polymer dosage influences both the aggregation mechanisms and the aggregate geometry. On the other hand, Yang [17] studied the flocculation of kaolin suspensions using small-angle laser light scattering. It was shown that the low molecular weight and highly charged polydiallyldimethylammonium chloride polymers induce aggregation by charge neutralization.…”

Section: Introductionmentioning

confidence: 99%

Comparison of two cationic polymeric flocculant architectures on the destabilization of negatively charged latex suspensions

Palomino

Hunkeler²,

Stoll

2011

Polymer

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This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues.Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal, institutional or third party websites are prohibited. Flocculation studies between cationic polymers and oppositely charged colloidal particles are reported in which both flocculation kinetics and floc structures are systematically investigated. The flocculation rate constant, stability ratio and kinetics laws are experimentally determined using particle counting for two polymer architectures; a cationic linear polymer and a two-branched polymer. Comparisons are also made using NaCl at different ionic concentrations for the destabilization of the colloidal particles. Detailed measurements of electrophoretic mobility and kinetics rate constants on varying the polymer dosage are reported. Results suggest that the polymer architecture plays important roles on the polymer dosage for the rapid destabilization of the colloidal suspension. The branched polymer at optimal dosage exhibits the highest flocculation rate constant, whereas on the other hand, the linear polymer concentration range of flocculation is larger. In both cases, polymer flocculation is more efficient by a factor of 5e6 than charge screening effects due to the presence of salt. Analysis of the stability ratio indicates that tele-bridging flocculation and electrostatic forces dictate the stability of the charged latex particle suspension. It is shown that the fractal concepts which are valid for aggregation processes are also applicable here and branched polymers as well as linear polymers yield to the formation of compact flocs in comparison to those obtained with salt.

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Flocculation of kaolin particles by two typical polyelectrolytes: A comparative study on the kinetics and floc structures

Cited by 111 publications

References 40 publications

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Characterization of kaolin flocs formed by polyacrylamide as flocculation aids

Coagulation of arsenic adsorbed ferrihydrite with the use of polyaluminium chloride (PAC) or polyferric sulfate (PFS)

Comparison of two cationic polymeric flocculant architectures on the destabilization of negatively charged latex suspensions

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