Effect of Polyelectrolyte Structural Features on Flocculation Behavior: Cationic Polysaccharides vs. Synthetic Polycations

Bratskaya, Svetlana; Schwarz, Simona; Laube, Johannes; Liebert, Tim; Heinze, Thomas; Krentz, Oliver; Lohmann, Claudia A.; Kulicke, Werner‐Michael

doi:10.1002/mame.200400403

Cited by 49 publications

(20 citation statements)

References 34 publications

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“…at low conductivity (Gregory, 1973). A greater tendency to patch flocculation is expected for branched polymers compared with linear polymers, and for high-molecular-weight polymers compared with lower-molecular-weight polymers (Bouyer et al, 2001;Bratskaya et al, 2005). However, since the conductivity of slurry is relatively high (see Sect.…”

Section: Theorymentioning

confidence: 99%

Solid—liquid separation of animal slurry in theory and practice. A review

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

335

235

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-Animal slurry contains plant nutrients that are essential for crop production. However, intensive livestock production may lead to a surplus of plant nutrients on farms and, as a consequence, discharge or emission to the environment. In order to ensure that the slurry applied to fields matches the nutrient requirements of the crops, techniques have been developed to reduce the nutrient content of slurry by means of separation. This review discusses the separation technologies used for animal slurry treatment and the physical and chemical processes involved in separation. These processes need to be understood before efficient, reliable and cheap separation technologies that take into account the actual properties of slurry and the likely end-use of the separation products can be developed. A simple separation efficiency expression can be used to assess the efficiency of slurry separation. It is indeed important to measure the amount and composition of the slurry before treatment, the dry-matter-rich fraction and the liquid fraction. The separation efficiency of mechanical separators for the removal of dry matter and phosphorus (P) is ranked as follows: centrifugation > sedimentation > non-pressurized filtration > pressurized filtration. In general, the separation of total N and NH + 4 follows the same pattern, but the separation efficiency is lower than for dry matter and P. Treatment with a flocculant before separation improves separation efficiency significantly. Of the polyacrylamide polymers tested, high-molecular-weight, linear cationic polymers with a medium charge density (20-40 mol%) were found to be the most efficient flocculants. The best mechanical separation techniques for flocculated slurry are screens or filter belts. The separation efficiency of polyacrylamide-treated slurry can be improved by adding a multivalent ion to coagulate particles and for precipitation of phosphorus. Aluminium sulfate (Al 2 (SO 4 ) 3 ) or ferric chloride (FeCl 3 ) seem to be very efficient for improving the mechanical separators. Alternatively, the mineral struvite (MgNH 4 PO 4 ) may be formed by changing the slurry characteristics, such as by the addition of magnesium (Mg) or by increasing the pH to 9. The struvite crystals are removed during solid-liquid separation. The products of the solid-liquid separation may be further treated by evaporation, membrane filtration or ammonia stripping in order to obtain the desired end-products; however, low-maintenance and/or cost-efficient operation of these post-treatments has not yet been demonstrated. The separation should be developed as a whole-system approach, paying attention to parameters such as the value of end-products, environmental consequences and economy.

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Section: Theorymentioning

confidence: 99%

Solid—liquid separation of animal slurry in theory and practice. A review

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

335

235

View full text Add to dashboard Cite

show abstract

“…Only a few studies have considered rheological properties from the point of view of paper strength 8, 9. Most studies have concentrated primarily on charge density of the polymer, polymer concentration, salt concentration,10 and dry substance content,6 whereas rheological studies have mostly concentrated on flocculation behavior 11. The stress behavior of modified MFC with increasing shear rate has been reported 12…”

Section: Introductionmentioning

confidence: 99%

The effect of water‐soluble polymers on rheology of microfibrillar cellulose suspension and dynamic mechanical properties of paper sheet

Vesterinen

Myllytie²,

Laine³

et al. 2010

J of Applied Polymer Sci

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Rheological properties of fiber/polymer suspensions and dynamic mechanical analysis (DMA) of paper sheets containing the same polymers were measured. Correlations between viscoelastic properties of suspensions and strength of paper sheet are presented. Rheological properties of suspensions of microfibrillar cellulose (MFC) and a set of water soluble polymers were measured. Rheological properties of these complex fluids vary considerably depending on the added polymer. A suspension of fiber and carboxymethyl cellulose (CMC) exhibits a viscosity higher than the sum of the viscosity of the individual components in the suspension. In contrast, when cationic starch (CS) is used together with the fiber, the yielding behavior rather than the viscosity is characteristic of the suspension. Dynamic mechanical properties of paper sheets containing CMC or CS as additives were studied at different humidity levels. Different yielding behavior observed in oscillatory rheology can be correlated with straining behavior in dynamic mechanical properties.

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“…Similarly, Zeta potential of R. erythropolis LSSE8-1 cells was −21.99 mV, and LSSE8-1 cells were flocculated from its culture broth by chitosan. Although the flocculation mechanism of chitosan has not been clearly recognized, 32 we consider that the combination of electrostatic interaction and bridging may play an important role in flocculation of P. delafieldii R-8.…”

Section: Methodsmentioning

confidence: 99%

Integration of flocculation and adsorptive immobilization of Pseudomonas delafieldii R-8 for diesel oil biodesulfurization

Gao

et al. 2010

J. Chem. Technol. Biotechnol.

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BACKGROUND: Deep desulfurization of hydrocarbon fuels is receiving increasing worldwide attention because of the increasingly stringent regulations to meet the requirement of environmental protection. Biodesulfurization (BDS) is being explored as either an alternative or complementary process to the conventional oil refining technologies. The whole cell immobilization technique is of great importance for accelerating the industrialization of BDS. An effective technique for a BDS process employing flocculation and integration with immobilization was developed.

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Effect of Polyelectrolyte Structural Features on Flocculation Behavior: Cationic Polysaccharides vs. Synthetic Polycations

Cited by 49 publications

References 34 publications

Solid—liquid separation of animal slurry in theory and practice. A review

Solid—liquid separation of animal slurry in theory and practice. A review

The effect of water‐soluble polymers on rheology of microfibrillar cellulose suspension and dynamic mechanical properties of paper sheet

Integration of flocculation and adsorptive immobilization of Pseudomonas delafieldii R-8 for diesel oil biodesulfurization

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