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Data associated with 'Structure and sedimentation characterisation of sheared Mg(OH)2 suspensions flocculated with anionic polymers'

Lockwood, Alexander (2021) Data associated with 'Structure and sedimentation characterisation of sheared Mg(OH)2 suspensions flocculated with anionic polymers'. University of Leeds. [Dataset] https://doi.org/10.5518/923

Dataset description

In this study, magnesium hydroxide (Mg(OH)2) suspensions were flocculated using two polyacrylamide-poly(acrylic acid) copolymers with charge densities of 30% or 40%. Structural characteristics, including particle size distribution, shape and fractal dimension of the resultant flocs were investigated using complementary techniques; static light scattering, focused beam reflectance measurement, automated optical microscopy and cryogenic scanning electron microscopy. Sedimentation rates were analysed for 2.5 vol.% dispersions at various polymer concentrations and compared to predictions from a fractal modified Richardson-Zaki (FMRZ) settling model. FMRZ model predictions using the 90th percentile (d90) floc sizes produced the most accurate correlations to experimental settling data, as these larger flocs likely dominate settling dynamics by ‘netting’ smaller particles. Overall, the FMRZ settling model provided a first approximation of zonal settling rates, but when further examined by multivariate analysis, it was found to be critically sensitive to small changes in fractal dimension.

Keywords:	Flocculation; Anionic polymers; Extended Stokes; Sedimentation modelling; Hindered settling
Subjects:	H000 - Engineering > H800 - Chemical, process & energy engineering > H810 - Chemical engineering
Divisions:	Faculty of Engineering and Physical Sciences > School of Chemical and Process Engineering
Related resources:	Location Type https://doi.org/10.1016/j.ces.2020.116274 Publication
License:	Creative Commons Attribution 4.0 International (CC BY 4.0)
Date deposited:	29 Apr 2021 10:55
URI:	http://archive.researchdata.leeds.ac.uk/id/eprint/834
Additional details Additional details Creators: Creators ORCID Other ID Email Primary affiliation Primary affiliation ID Primary affiliation ID type Secondary affiliation Secondary affiliation ID Secondary affiliation ID type Lockwood, Alexander https://orcid.org/0000-0002-2111-6753 University Of Leeds http://dx.doi.org/10.13039/501100000777 crossref Type of data: Dataset Research funders: EPSRC Grant numbers: EP/L015390/1 Publication date: 29 April 2021 Resource language: English Publisher: University of Leeds Contact Email Address: pm12a2l@leeds.ac.uk Last Modified: 04 May 2021 12:16

Files

Data

Figs 1Ai & 1Aii [90kB] Figs 1Ai & 1Aii [90kB] Figs 1Ai & 1Aii [90kB] Visible to: Anyone File name: Fig_1Ai_Fig_1Aii.opju Content type: Data Description: A (i) & A (ii) Median volume weighted particle size (d50) over time, measured with a focused beam reflectance meter (FBRM), for 2.5 vol.% Mg(OH)2 suspensions agitated at 300 rpm, flocculated with 30%σ and 40%σ anionic polymers respectively, dosed at 5, 10 License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 90kB

Fig 1B [50kB] Fig 1B [50kB] Fig 1B [50kB] Visible to: Anyone File name: Fig_1B.opju Content type: Data Description: B) Cumulative volume distribution of floc sizes for the same systems dosed at 20 ppm, measured by FBRM after 1000 s. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 50kB

Fig 2A [39kB] Fig 2A [39kB] Fig 2A [39kB] Visible to: Anyone File name: Fig_2A.opju Content type: Data Description: A) Static light scattering (SLS) particle size distributions of 2.5 vol.% Mg(OH)2 suspensions with addition of 20 ppm 30%σ and 40%σ polymers, compared to sonicated Mg(OH)2 with no polymer. Represented are continuous distributions for measurement bin sizes License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 39kB

Fig 2B [35kB] Fig 2B [35kB] Fig 2B [35kB] Visible to: Anyone File name: Fig_2B.opju Content type: Data Description: B) SLS fractal dimension analysis of 2.5 vol.% Mg(OH)2 suspensions with 30%σ and 40%σ polymer. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 35kB

Fig 2Ci & 2Cii [66kB] Fig 2Ci & 2Cii [66kB] Fig 2Ci & 2Cii [66kB] Visible to: Anyone File name: Fig_2Ci_2Cii.opju Content type: Data Description: C) Kinetics of floc shear from shear degradation, showing (i) change in median diameter d50 with time and (ii) densification of Mg(OH)2 with 20 ppm 30%σ and 40%σ polymers. All samples prepared in a reactor vessel at 300 rpm for 1000 s, then subsampled int License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 66kB

Fig 3A [39kB] Fig 3A [39kB] Fig 3A [39kB] Visible to: Anyone File name: Fig_3A.opju Content type: Data Description: A) Aspect ratio distribution License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 39kB

Fig 3B [41kB] Fig 3B [41kB] Fig 3B [41kB] Visible to: Anyone File name: Fig_3B.opju Content type: Data Description: B) cumulative frequency distribution, for optical image analysis of 2.5 vol.% Mg(OH)2 suspensions agitated for 1000 s at 300 rpm with 30%σ and 40%σ polymers dosed at 20 ppm. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 41kB

Fig 4 [208kB] Fig 4 [208kB] Fig 4 [208kB] Visible to: Anyone File name: Fig_4.tif Content type: Data Description: Example optical microscope image of Mg(OH)2 suspensions mixed with 20 ppm 30%σ polymer. Mime-Type: image/tiff License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 208kB

Fig 5 [734kB] Fig 5 [734kB] Fig 5 [734kB] Visible to: Anyone File name: Fig_5.tif Content type: Data Description: Cryo-SEM images of 2.5 vol.% Mg(OH)2 suspensions mixed with 20 ppm 40%σ polymer. A) 19982x magnification, B) 35000x magnification and C) 99959x magnification. Mime-Type: image/tiff License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 734kB

Fig 6Ai & 6Aii [121kB] Fig 6Ai & 6Aii [121kB] Fig 6Ai & 6Aii [121kB] Visible to: Anyone File name: Fig_6Ai_6Aii.opju Content type: Data Description: A) Interface height versus time for flocculated 2.5 vol.% Mg(OH)2 with varying concentrations of (i) 30%σ and (ii) 40%σ polymer, prepared in a reactor agitated at 300 rpm for 1000 s. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 121kB

Fig 6B [42kB] Fig 6B [42kB] Fig 6B [42kB] Visible to: Anyone File name: Fig_6B.opju Content type: Data Description: B) Linear zonal settling rate versus polymer concentrations for the same systems. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 42kB

Fig 7A [69kB] Fig 7A [69kB] Fig 7A [69kB] Visible to: Anyone File name: Fig_7A.opju Content type: Data Description: A) Comparison of measured (actual) zonal settling rates (dashed lines) for flocculated 2.5 vol.% Mg(OH)2 suspensions mixed with 20 ppm 30%σ (df = 2.07) and 40%σ (df = 2.09) polymer, to those predicted by the fractal modified Richardson-Zaki equation (Eqn. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 69kB

Fig 7B [65kB] Fig 7B [65kB] Fig 7B [65kB] Visible to: Anyone File name: Fig_7B.opju Content type: Data Description: B) Comparison of measured and predicted data as A), assuming identical fractal properties for both flocculated polymer systems (df = 2.07). License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 65kB

Fig 8A [1MB] Fig 8A [1MB] Fig 8A [1MB] Visible to: Anyone File name: Fig_8A.opju Content type: Data Description: A) FMRZ model prediction of the zonal settling rate of 2.5 vol.% Mg(OH)2 suspensions mixed with 20 ppm 30%σ polymer, for various input floc sizes, (D_f ) ̅, and fractal dimensions, df , based on the fractal modification of the Richardson-Zaki equation (Eq License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 1MB

Fig 8B [46kB] Fig 8B [46kB] Fig 8B [46kB] Visible to: Anyone File name: Fig_8B.opju Content type: Data Description: B) The change in the floc particle number, (N_f ) ̅, as a function of floc diameter and fractal dimension for (D_f ) ̅=100,500 and 900 μm, selected to cover the experimental range. License: Creative Commons Attribution 4.0 International (CC BY 4.0) File size: 46kB