Influence of COM-peptides/proteins on the properties of flocs formed at different shear rates

Filipenská, Monika; Vašatová, Petra; Pivokonská, Lenka; Čermáková, Lenka; Gonzalez-Torres, A.; Henderson, Rita K.; Načeradská, Jana; Pivokonský, Martin

doi:10.1016/j.jes.2018.11.025

Cited by 10 publications

(12 citation statements)

References 42 publications

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“…As a result of these interactions, polymeric flocculants and suspended particles can form large flocs with a three-dimensional network structure . Flocs generated by using a polymer with a larger molecular weight can be larger and have a looser structure. , The porosity or compactness of flocs can also affect their settling velocity as fluid can easily pass through the networks of porous flocs. , It is interesting to note that the configurational changes of polymers caused by altering polymeric chain, chemical composition, and morphology can also affect their flocculation behavior and floc properties, such as floc strength, structure, and sizes. Previously, lignin–diallyldimethylammonium chloride–acrylamide (LDA), a cationic macromolecule with a broad structure, was synthesized and used as a flocculant for humic acid removal, which resulted in the formation of flocs with an open structure and strong antishear affinity .…”

Section: Introductionmentioning

confidence: 99%

Phenomenological Changes in Lignin Following Polymerization and Its Effects on Flocculating Clay Particles

Sabaghi

Fatehi

2019

Biomacromolecules

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Cationic kraft lignin (CKL) macromolecules were produced via polymerizing kraft lignin (KL) with [2-(acryloyloxy)ethyl]trimethylammonium chloride (ATAC) or [2-(methacryloyloxy)ethyl]trimethylammonium methyl sulfate (METAM). Despite slightly different charge densities (2.3−2.5 mmol/g) of CKL, lignin−METAM (KL−METAM) had a significantly larger molecular weight and radius of gyration. A correlation was observed between the structure of CKLs and their impacts on the surface hydrophilicity of kaolin particles. In interacting with kaolin particles, KL−METAM generated larger and stronger flocs with looser structures than did KL−ATAC. Compared to ATAC, METAM had one additional methyl substituent on its structure, which provided fundamental evidence on how a small group (i.e., a methyl group) on the structure of a cationic monomer can have a substantial influence on its polymerization with lignin and subsequently on the efficiency of the induced macromolecule as a flocculant in a kaolin suspension system.

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Section: Introductionmentioning

confidence: 99%

Phenomenological Changes in Lignin Following Polymerization and Its Effects on Flocculating Clay Particles

Sabaghi

Fatehi

2019

Biomacromolecules

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“…In practice, the raw water composition is given; therefore, only the type and dose of a coagulant and the coagulation pH value can be chosen and adjusted. Providing that optimal coagulation conditions are set, floc properties are further influenced primarily by the mixing intensity (see Section 2.3.3) (Bache & Rasool, 2001;Bache et al, 1999;Bouyer et al, 2005;Bubakova et al, 2013;Coufort et al, 2005Coufort et al, , 2007Filipenska et al, 2019;Francois, 1987;Gorczyca & Ganczarczyk, 1999;Li et al, 2006;Mutl et al, 2006;Pivokonsky et al, 2011;Serra et al, 2008;Spicer et al, 1998;Xu et al, 2010). The other significant factors influencing mainly the floc size distribution are the mixing time (see Section 2.3.4) and the velocity gradient (shear rate) distribution within the mixed volume (Bubakova et al, 2013;Coufort et al, 2005Coufort et al, , 2007Filipenska et al, 2019;Mutl et al, 2006).…”

Section: Summarising Boxmentioning

confidence: 99%

“…Providing that optimal coagulation conditions are set, floc properties are further influenced primarily by the mixing intensity (see Section 2.3.3) (Bache & Rasool, 2001;Bache et al, 1999;Bouyer et al, 2005;Bubakova et al, 2013;Coufort et al, 2005Coufort et al, , 2007Filipenska et al, 2019;Francois, 1987;Gorczyca & Ganczarczyk, 1999;Li et al, 2006;Mutl et al, 2006;Pivokonsky et al, 2011;Serra et al, 2008;Spicer et al, 1998;Xu et al, 2010). The other significant factors influencing mainly the floc size distribution are the mixing time (see Section 2.3.4) and the velocity gradient (shear rate) distribution within the mixed volume (Bubakova et al, 2013;Coufort et al, 2005Coufort et al, , 2007Filipenska et al, 2019;Mutl et al, 2006). While the mixing intensity and time can be adjusted to prepare flocs with properties suitable for the required type of separation, the need for the homogeneous distribution of the tangential forces is hard to achieve in practice.…”

Section: Summarising Boxmentioning

confidence: 99%

“…Similarly, Gonzalez-Torres et al (2014), who coagulated M. aeruginosa cells with aluminium sulphate and ferric chloride, revealed that Fe-cell flocs were larger than Al-cell flocs. Filipenska et al (2019) coagulated kaolin and/or COM of M. aeruginosa with aluminium and ferric sulphate and revealed larger flocs in the case of Fe. It was suggested that Fe tends to produce larger hydrolysis products than Al, as the Fe-O distance in the hydrated ion [Fe(H (Persson, 2010).…”

Section: Effect Of Coagulant Type On Floc Propertiesmentioning

confidence: 99%

“…It was suggested that Fe tends to produce larger hydrolysis products than Al, as the Fe-O distance in the hydrated ion [Fe(H (Persson, 2010). Additionally, Filipenska et al (2019) offered two more possible explanations related rather to coagulation optimisation, namely, that the optimal doses of Fe-based coagulants are often higher than those of Al-based coagulants (therefore producing larger amounts of precipitates) or that the biopolymers contained in AOM may have a spatially larger arrangement at a more acidic pH, which is more favourable for Fe-based coagulation than for Al-based coagulation.…”

Section: Effect Of Coagulant Type On Floc Propertiesmentioning

confidence: 99%

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Jar Tests for Water Treatment Optimisation

Pivokonský¹,

Novotná²,

Čermáková³

et al. 2022

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The book is intended as a handbook providing detailed instructions for the correct conducting of jar tests, which are needed for the optimisation of the coagulation/flocculation process. It contains the essential theoretical background of coagulation/flocculation, including a description of the influence of different parameters on the coagulation efficiency of various impurities (e.g. pH value and type/dose of coagulant), and floc properties and their separation (e.g. mixing intensity, mixing time, but also type/concentration of coagulant and impurities). The principle of jar tests is explained and parameters possible to optimize (i.e. coagulation pH, coagulant dose, flocculation aid dose, mixing intensity and mixing time) are discussed. Laboratory equipment for jar tests is proposed, including mixers and instructions for calculating a mixing intensity (necessarily expressed by the global shear rate/velocity gradient G). Mixing intensities for various purposes are recommended. Detailed practical instructions of how to perform jar tests follow, including a determination of the dose of reagents for pH adjustment and coagulant dose, dosing sequence, floc separation after jar tests by sedimentation and/or centrifugation simulating sand filtration, sampling, measuring necessary parameters (pH, coagulant residuals, alkalinity, residual impurity concentrations etc.), data recording, data processing and jar test evaluation (with specific examples). The handbook also contains a supplementary part with tables for conversion of the molar to mass concentration (and vice versa) of coagulants, and instructions for diluting coagulants and reagents for pH adjustment. ISBN: 9781789062687 (paperback) ISBN: 9781789062694 (eBook) ISBN: 9781789062700 (ePUB)

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Quantifying the 3D structure and function of porosity and pore space in natural sediment flocs

et al. 2022

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Purpose Flocculated cohesive suspended sediments (flocs) play an important role in all aquatic environments, facilitating the transport and deposition of sediment and associated contaminants with consequences for aquatic health, material fluxes, and morphological evolution. Accurate modelling of the transport and behaviour of these sediments is critical for a variety of activities including fisheries, aquaculture, shipping, and waste and pollution management and this requires accurate measurement of the physical properties of flocs including porosity. Methods Despite the importance of understanding floc porosity, measurement approaches are indirect or inferential. Here, using μCT, a novel processing and analysis protocol, we directly quantify porosity in natural sediment flocs. For the first time, the complexity of floc pore spaces is observed in 3-dimensions, enabling the identification and quantification of important pore space and pore network characteristics, namely 3D pore diameter, volume, shape, tortuosity, and connectivity. Results We report on the complexity of floc pore space and differentiate effective and isolated pore space enabling new understanding of the hydraulic functioning of floc porosity. We demonstrate that current methodological approaches are overestimating floc porosity by c. 30%. Conclusion These new data have implications for our understanding of the controls on floc dynamics and the function of floc porosity and can improve the parameterisation of current cohesive sediment transport models.

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Influence of COM-peptides/proteins on the properties of flocs formed at different shear rates

Cited by 10 publications

References 42 publications

Phenomenological Changes in Lignin Following Polymerization and Its Effects on Flocculating Clay Particles

Phenomenological Changes in Lignin Following Polymerization and Its Effects on Flocculating Clay Particles

Jar Tests for Water Treatment Optimisation

Quantifying the 3D structure and function of porosity and pore space in natural sediment flocs

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