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Sadegh-Vaziri R, Ludwig K, Sundmacher K, Babler MU. Mechanisms behind overshoots in mean cluster size profiles in aggregation-breakup processes. J Colloid Interface Sci 2018; 528:336-348. [PMID: 29885609 DOI: 10.1016/j.jcis.2018.05.064] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 04/25/2018] [Accepted: 05/21/2018] [Indexed: 10/16/2022]
Abstract
Aggregation and breakup of small particles in stirred suspensions often shows an overshoot in the time evolution of the mean cluster size: Starting from a suspension of primary particles the mean cluster size first increases before going through a maximum beyond which a slow relaxation sets in. Such behavior was observed in various systems, including polymeric latices, inorganic colloids, asphaltenes, proteins, and, as shown by independent experiments in this work, in the flocculation of microalgae. This work aims at investigating possible mechanism to explain this phenomenon using detailed population balance modeling that incorporates refined rate models for aggregation and breakup of small particles in turbulence. Four mechanisms are considered: (1) restructuring, (2) decay of aggregate strength, (3) deposition of large clusters, and (4) primary particle aggregation where only aggregation events between clusters and primary particles are permitted. We show that all four mechanisms can lead to an overshoot in the mean size profile, while in contrast, aggregation and breakup alone lead to a monotonic, "S"-shaped size evolution profile. In order to distinguish between the different mechanisms simple protocols based on variations of the shear rate during the aggregation-breakup process are proposed.
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Affiliation(s)
- Ramiar Sadegh-Vaziri
- Department of Chemical Engineering, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden
| | - Kristin Ludwig
- Max Planck Institute for Dynamics of Complex Technical Systems, Process Systems Engineering, Sandtorstr. 1, 39106 Magdeburg, Germany
| | - Kai Sundmacher
- Max Planck Institute for Dynamics of Complex Technical Systems, Process Systems Engineering, Sandtorstr. 1, 39106 Magdeburg, Germany; Otto von Guericke University Magdeburg, Process Systems Engineering, Universitätsplatz 2, 39106 Magdeburg, Germany
| | - Matthaus U Babler
- Department of Chemical Engineering, KTH Royal Institute of Technology, SE-10044 Stockholm, Sweden.
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2
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Torfs E, Dutta A, Nopens I. Investigating kernel structures for Ca-induced activated sludge aggregation using an inverse problem methodology. Chem Eng Sci 2012. [DOI: 10.1016/j.ces.2011.06.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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3
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Ehrl L, Soos M, Wu H, Morbidelli M. Effect of flow field heterogeneity in coagulators on aggregate size and structure. AIChE J 2010. [DOI: 10.1002/aic.12179] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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4
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Wang Y, Gao B, Yue Q, Zhan X, Si X, Li C. Flocculation performance of epichlorohydrin-dimethylamine polyamine in treating dyeing wastewater. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2009; 91:423-431. [PMID: 19781846 DOI: 10.1016/j.jenvman.2009.09.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2008] [Revised: 08/17/2009] [Accepted: 09/01/2009] [Indexed: 05/28/2023]
Abstract
Epichlorohydrin-dimethylamine polymers with different intrinsic viscosity (eta) and cationicity (tau) were synthesized. The flocculation performance and mechanism of these polymers in the removal of the reactive and disperse dyes from synthetic wastewater was investigated in terms of flocculation dynamics and color removal efficiency. The polymer flocculation efficiency was compared with that of polyaluminum chloride (PAC) and a composite flocculant based on polyaluminum chloride-epichlorohydrin-dimethylamine polyamine. The results showed that epichlorohydrin-dimethylamine polymer was effective over a pH range of 2-10 for the reactive and disperse dye removal (Reactive Brilliant Red and Disperse Yellow dyes). Epichlorohydrin-dimethylamine polymer with the highest eta and tau gave the best reactive dye removal efficiency, and its adsorption-bridging and electric neutralization ability played important roles in the flocculation process. The higher the eta viscosity of the epichlorohydrin-dimethylamine polymer, the better the flocculation performance of epichlorohydrin-dimethylamine polyamine, and stronger adsorption-bridging ability was obtained for removing the disperse dye from dyeing wastewaters. Epichlorohydrin-dimethylamine polymer achieved better decolorization performance when used together with PAC.
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Affiliation(s)
- Yuanfang Wang
- School of Environmental Science and Engineering, Shandong University, Jinan 250100, PR China
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5
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Effect of coagulation conditions on the dewatering properties of sludges produced in drinking water treatment. Colloids Surf A Physicochem Eng Asp 2009. [DOI: 10.1016/j.colsurfa.2009.06.013] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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6
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Cheng J, Yang C, Mao ZS, Zhao C. CFD Modeling of Nucleation, Growth, Aggregation, and Breakage in Continuous Precipitation of Barium Sulfate in a Stirred Tank. Ind Eng Chem Res 2009. [DOI: 10.1021/ie9004282] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jingcai Cheng
- Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Jiangsu Marine Resources Development Research Institute, Lianyungang 222005, China; and Shijiazhuang Chemical Fiber Corporation, Hebei 050032, China
| | - Chao Yang
- Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Jiangsu Marine Resources Development Research Institute, Lianyungang 222005, China; and Shijiazhuang Chemical Fiber Corporation, Hebei 050032, China
| | - Zai-Sha Mao
- Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Jiangsu Marine Resources Development Research Institute, Lianyungang 222005, China; and Shijiazhuang Chemical Fiber Corporation, Hebei 050032, China
| | - Chengjun Zhao
- Key Laboratory of Green Process and Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing 100190, China; Jiangsu Marine Resources Development Research Institute, Lianyungang 222005, China; and Shijiazhuang Chemical Fiber Corporation, Hebei 050032, China
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7
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Bäbler MU. A collision efficiency model for flow-induced coagulation of fractal aggregates. AIChE J 2008. [DOI: 10.1002/aic.11496] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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8
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Kilander J, Blomström S, Rasmuson A. Scale-up behaviour in stirred square flocculation tanks. Chem Eng Sci 2007. [DOI: 10.1016/j.ces.2006.06.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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9
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Prat O, Ducoste J. Simulation of Flocculation in Stirred Vessels Lagrangian Versus Eulerian. Chem Eng Res Des 2007. [DOI: 10.1205/cherd05001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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10
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Zucca A, Marchisio DL, Vanni M, Barresi AA. Validation of bivariate DQMOM for nanoparticle processes simulation. AIChE J 2007. [DOI: 10.1002/aic.11125] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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11
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Kilander J, Blomström S, Rasmuson A. Spatial and temporal evolution of floc size distribution in a stirred square tank investigated using PIV and image analysis. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2006.09.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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12
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Maximova N, Dahl O. Environmental implications of aggregation phenomena: Current understanding. Curr Opin Colloid Interface Sci 2006. [DOI: 10.1016/j.cocis.2006.06.001] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Negro C, Sánchez LM, Fuente E, Blanco Á, Tijero J. Polyacrylamide induced flocculation of a cement suspension. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2005.11.013] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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14
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15
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Zucca A, Marchisio DL, Barresi AA, Fox RO. Implementation of the population balance equation in CFD codes for modelling soot formation in turbulent flames. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2004.11.061] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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16
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Prat OP, Ducoste JJ. Modeling spatial distribution of floc size in turbulent processes using the quadrature method of moment and computational fluid dynamics. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2004.11.070] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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17
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Population balance modelling of activated sludge flocculation: Investigating the size dependence of aggregation, breakage and collision efficiency. Chem Eng Sci 2006. [DOI: 10.1016/j.ces.2005.02.074] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Bouyer D, Coufort C, Liné A, Do-Quang Z. Experimental analysis of floc size distributions in a 1-L jar under different hydrodynamics and physicochemical conditions. J Colloid Interface Sci 2005; 292:413-28. [PMID: 16054637 DOI: 10.1016/j.jcis.2005.06.011] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2005] [Revised: 06/01/2005] [Accepted: 06/04/2005] [Indexed: 11/28/2022]
Abstract
This study focuses on the relation among hydrodynamics, physicochemical conditions, and floc size. During ortho-kinetic flocculation, the floc size is controlled by a balance between hydrodynamic stress and aggregate strength. Special attention was paid to the influence of a hydrodynamic sequencing on both the aggregate strength and the flocculation processes. Experimental research was conducted in a 1-L jar for two different pH values. The hydrodynamic sequencing was made up of successive slow and rapid mixing periods, and different slow mixing intensities were studied. First, the large floc size was shown to decrease with increasing velocity gradient (G), with an expected trend (d proportional variant epsilon(-1/4)). Then, the aggregate strength was shown to depend on two main factors: the flocculation history and the physicochemical conditions, which control the cohesion forces between primary particles. Finally, flocculation processes are discussed in terms of aggregation and breakup phenomena, with relation to local hydrodynamics and physicochemical conditions.
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Affiliation(s)
- Denis Bouyer
- L.I.P.E., I.N.S.A., 135 Avenue de Rangueil, 31077 Toulouse cedex, France
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Runkana V, Somasundaran P, Kapur PC. Reaction-limited aggregation in presence of short-range structural forces. AIChE J 2005. [DOI: 10.1002/aic.10375] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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20
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Comparison and pitfalls of different discretised solution methods for population balance models: a simulation study. Comput Chem Eng 2005. [DOI: 10.1016/j.compchemeng.2004.10.007] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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21
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Nopens I, Koegst T, Mahieu K, Vanrolleghem PA. PBM and activated sludge flocculation: From experimental data to calibrated model. AIChE J 2005. [DOI: 10.1002/aic.10402] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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22
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Runkana V, Somasundaran P, Kapur PC. Mathematical modeling of polymer-induced flocculation by charge neutralization. J Colloid Interface Sci 2004; 270:347-58. [PMID: 14697700 DOI: 10.1016/j.jcis.2003.08.076] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A detailed mathematical model for flocculation of colloidal suspensions in presence of salts and polymers is described and validated. In former case, the classical DLVO theory, which accounts for relevant variables such as pH and salt concentration, is incorporated into a geometrically sectioned discrete population balance model. For processes involving polymers, flocculation via simple charge neutralization is modeled using a modified DLVO theory in which the effect of adsorbed polymer layers on van der Waals attraction is included. The fractal dimension of aggregates is obtained by dynamic scaling of experimental data for time evolution of mean aggregate size. The particle surface potential is assumed to be approximately equal to the zeta potential. The model predictions are in close agreement with experimental results for flocculation of colloidal hematite suspensions in the presence of KCl and polyacrylic acid at different concentrations. In particular, given values of model parameters, e.g., Hamaker constant, fractal dimension, surface potential, and thickness of adsorbed polymer layer, the model can realistically describe the kinetics of flocculation by a simple charge neutralization mechanism and track the evolution of floc size distribution. Representative examples of sensitivity of the flocculation model to perturbations in surface potential and fractal dimension and to modification in the DLVO theory for polymer-coated particles are included.
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Affiliation(s)
- Venkataramana Runkana
- NSF Industry/University Cooperative Research Center for Advanced Studies in Novel Surfactants, Columbia University, New York, NY 10027, USA
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Hopkins DC, Ducoste JJ. Characterizing flocculation under heterogeneous turbulence. J Colloid Interface Sci 2003; 264:184-94. [PMID: 12885534 DOI: 10.1016/s0021-9797(03)00446-6] [Citation(s) in RCA: 110] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
This study investigated the impact of turbulent heterogeneity in a flocculation reactor on particle aggregation and breakup. In particular, the influence of average characteristic velocity gradient (G), particle concentration, and coagulation mechanism (sweep floc vs charge neutralization) on the floc growth, steady-state size, and variance was analyzed. Experiments were performed in a bench-scale reactor with a low-shear axial-flow impeller using a photometric dispersion analyzer (PDA). Results indicated that as G increased, floc growth increased while the mean size and variance in the floc size distribution decreased. In addition, floc growth, mean size, and variance increased with increasing primary particle concentration and when the coagulation mechanism was switched from charge neutralization to sweep floc. Lastly, floc growth, mean size, and variance were found to vary spatially in the reactor at low G values with larger floc size and growth rate in the bulk region and a larger variance in the impeller discharge region.
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Affiliation(s)
- D Cory Hopkins
- Department of Civil Engineering, North Carolina State University, 208 Mann Hall, Raleigh, NC 27695-7908, USA
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