Flocculation of colloidal clay by bacterial polysaccharides: effect of macromolecule charge and structure

Labille, Jérôme; Thomas, Fabien; Milas, M.; Vanhaverbeke, Cécile

doi:10.1016/j.jcis.2004.10.001

Cited by 83 publications

(51 citation statements)

References 45 publications

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“…2). This is consistent with a model describing the biopolymer as a more rigid chain than PAM (Holzwarth and Prestridge, 1977;Labille et al, 2004), with less flexibility and ability to conform to irregular soil surfaces as chain length decreased. An alternative explanation is that the treatment biopolymer concentration was below the critical value needed for BP-L to stabilize soil aggregates.…”

Section: Aggregate Stabilitysupporting

confidence: 89%

“…During the experiment, we noted that the viscosity of the PAM-1 solution was more viscous than that of BP-1, which lends support to the argument that PAM molecules exhibited greater extension in solution than the biopolymer molecules. Many polysaccharides adopt a single helix or double helix conformation in solution, which makes them less flexible than the linear, single-chain, PAM (Holzwarth and Prestridge, 1977;Labille et al, 2004). He and Horikawa (1996) attributed biopolymer-induced dispersion at very dilute concentrations, not observed for PAM polymer, to the reduced flexibility of the polysaccharide.…”

Section: Flocculation Efficacymentioning

confidence: 99%

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Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam

Lentz¹

2015

Geoderma

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Researchers seek a more renewable and natural alternative for water soluble anionic polyacrylamide (PAM), a highly-effective, petroleum-derived polymer used in agriculture to control erosion and reduce water seepage from unlined irrigation structures. This study evaluated four anionic polymers including low-(0.5 Mg mol , high-MW biopolymer or PAM solutions were applied to silt loam. The biopolymer most effectively flocculated the colloids at a concentration of 1 mg L −1 , but was still 30% less effective than PAM at 1 mg L −1 and 50% less effective than PAM at 10 mg L −1. Overall, both polymer types increased the percent of stable soil aggregates in the silt loam, 1-to-2-mm-diam. size fraction, though PAM produced 1.35-times more stable aggregates than the biopolymer, 88.7% vs. 65.5%. These results suggested that the biopolymer's bulkier molecular conformation limited the extension and flexibility of the molecule in solution, compared to PAM. After 140 h, the biopolymer reduced seepage loss rates by 21%, while PAM increased loss rates 1.6-fold, compared to controls. These data suggest that the biopolymer would be less effective than PAM for reducing water erosion owing to its lesser flocculation and aggregatestabilizing potential. However, the biopolymer could be a more desirable alternative to PAM for controlling seepage from unlined irrigation canals and reservoirs; it (i) can be used effectively at lower concentrations, (ii) is considered more environmentally friendly, and (iii) is produced from a renewable resource.Published by Elsevier B.V.

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Section: Aggregate Stabilitysupporting

confidence: 89%

Section: Flocculation Efficacymentioning

confidence: 99%

Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam

Lentz¹

2015

Geoderma

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“…Carboxylate groups interact electrostatically with the positively charged edges and layer sites of the Na-montmorillonite platelets and form strong bonds [23]. Rhamnosyl moities have a polyalcohol structure and their -OH groups form hydrogen bridges with the faces of the Na-montmorillonite platelets [24]. As a result of these intense interactions, the expansion of clay through the intercalation of RL molecules and the distribution of clay platelets in water through the anchoring of the molecules on the edge groups are expected.…”

Section: Interactions Of Rls With Na-montmorillonitementioning

confidence: 99%

Adsorption and desorption behavior of copper ions on Na-montmorillonite: Effect of rhamnolipids and pH

Özdemir

Yapar

2009

Journal of Hazardous Materials

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“…Additionally, natural or synthetic polymeric substances are used as coagulants alone or as coagulant aids together with metal salts. A number of natural materials have coagulating abilities such as chitosan, starch and alginate (Ahmad et al 2006;Devrimci et al 2012;Divakaran and Pillai 2002;Guibal and Roussy 2007;Labille et al 2005;Madrona et al 2010;Qudsieh et al 2008;Sand et al 2010;Tripathy and Singh 2001). Natural polymers are advantageous because they are less toxic and more biodegradable (Bolto and Gregory 2007).…”

Section: Introductionmentioning

confidence: 99%

Guluronic acid content as a factor affecting turbidity removal potential of alginate

Moral

Ertesvåg

Sanin

2016

Environ Sci Pollut Res

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Alginates are natural polymers composed of mannuronic and guluronic acid residues.They are currently extracted from brown algae, however, alginate can also be synthesized by some species of Azotobacter and Pseudomonas. Alginates with different proportion of mannuronic and guluronic acids are known to have different characteristics and form gels at different extents in the presence of calcium ions. The aim of this work was to investigate the usefulness of alginate as a non-toxic coagulant used in purification of drinking water. This study utilized alginates from Azotobacter vinelandii having different guluronic acid levels. These were obtained partly by changing the cultivation parameters, partly by epimerizing a purified alginate sample in vitro using the A. vinelandii mannuronan-C-5-epimerase AlgE1. The different alginates were then used for coagulation together with calcium. The results showed that turbidity removal capability was dependent on the content of guluronic acid residues. For the best performing samples the turbidity decreased from 10 NTU to 1 NTU by the use of only 2 mg/L of alginate and 1.5 mM of calcium chloride.

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Flocculation of colloidal clay by bacterial polysaccharides: effect of macromolecule charge and structure

Cited by 83 publications

References 45 publications

Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam

Polyacrylamide and biopolymer effects on flocculation, aggregate stability, and water seepage in a silt loam

Adsorption and desorption behavior of copper ions on Na-montmorillonite: Effect of rhamnolipids and pH

Guluronic acid content as a factor affecting turbidity removal potential of alginate

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