Flocculation behavior of some cationic polyelectrolytes

Smith‐Palmer, Truis; Campbell, Nicole; Bowman, Janice L.; Dewar, Patricia J.

doi:10.1002/app.1994.070520916

Cited by 22 publications

(11 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Flocculation, coagulation and precipitation are chemical pre-treatments that improve the mechanical solid-liquid separation of many suspensions (Gregory, 1973;Smith-Palmer et al, 1994;Ashmore and Hearn, 2000;Nowostawska et al, 2005). In most suspensions, colloidal particles will not aggregate because the particles are negatively charged and repel each other (Gregory, 1989).…”

Section: Precipitation Coagulation and Flocculationmentioning

confidence: 99%

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

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

336

235

View full text Add to dashboard Cite

-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.

show abstract

Section: Precipitation Coagulation and Flocculationmentioning

confidence: 99%

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

Hjorth

Christensen

et al. 2010

Agron. Sustain. Dev.

336

235

View full text Add to dashboard Cite

show abstract

“…The charge neutralization of colloidal particles with patches of adsorbed polyelectrolytes [3][4][5][6][7] or the formation of bridges between colloidal particles by simultaneous adsorption of polyelectrolyte chains onto more than two particles [8][9][10][11] are recognized as mechanisms that induce flocculation. In either case, the adsorption of polyelectrolytes onto the surface of colloidal particles induces the flocculation of colloidal particles.…”

Section: Introductionmentioning

confidence: 99%

Kinetics of polyelectrolyte adsorption onto polystyrene latex particle studied using electrophoresis: Effects of molecular weight and ionic strength

Aoki

Adachi

2006

Journal of Colloid and Interface Science

View full text Add to dashboard Cite

“…Previous studies on such systems have also attributed a limited dependence of the settling rate on the charge density to the predominance of a bridging mode of action. 12,18 In contrast, the settling rates at higher polymer concentrations were vastly different from each other. The settling rates resulting from CPAM35 addition dramatically decreased after the addition of 0.1 mg CPAM35/m 2 kaolin, whereas increasing the amount of PAM past this point resulted in even higher settling rates, with a plateau (with a slight rise) after the addition of 0.15 mg PAM35/m 2 kaolin.…”

Section: Discussionmentioning

confidence: 83%

“…CPC was chosen because its strong UV absorptivity enabled us to determine its residual concentration after adsorption without interference from the polymer solutions, providing they were prepared in a pH 4.1 acetate buffer rather than the biphthalate used previously. 12 The polyelectrolytes were prepared in buffer to prevent hydrolysis of the ester linkages.…”

Section: Resultsmentioning

confidence: 99%

“…The increased efficiency of the CPAM35 as compared to PAM was attributed to the greater extension of its chains because of repulsion between the charged groups. 12 The nonionic polymer had a molecular weight twice that of the cationic polymer and on this basis might have been expected to produce the higher settling rate. Previous studies on such systems have also attributed a limited dependence of the settling rate on the charge density to the predominance of a bridging mode of action.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

The flocculation of kaolin by cationic polyacrylamides and the effect of cationic surfactant on this process

McCarron

Crispo

Smith‐Palmer

2002

J of Applied Polymer Sci

Self Cite

View full text Add to dashboard Cite

ABSTRACT:The flocculation of kaolin suspended in a dilute salt solution was studied as a function of the addition of cationic surfactant and cationic polyacrylamide (CPAM) added separately, consecutively, or simultaneously. Cationic polyacrylamide caused flocculation by bridging when added in low concentrations, but at higher concentrations, charge neutralization became the dominant mechanism and the flocculation rate was highly dependent on the charge density of the polymer. Adsorption of sufficient polymer or surfactant (cetyl pyridinium chloride) prevented immediate adsorption of the other, although surfactant could replace polymer after extended agitation. The adsorption of polymer was greatest when small flocs were formed by charge neutralization or by prolonged shaking.

show abstract

Flocculation behavior of some cationic polyelectrolytes

Cited by 22 publications

References 19 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

Kinetics of polyelectrolyte adsorption onto polystyrene latex particle studied using electrophoresis: Effects of molecular weight and ionic strength

The flocculation of kaolin by cationic polyacrylamides and the effect of cationic surfactant on this process

Contact Info

Product

Resources

About