For colloidal systems with adsorbed polymer, the mechanisms governing stabilization and flocculation are defined by the critical overlap concentration, c*. Below c*, steric stabilization or bridging flocculation are viable mechanisms of adsorption, while above c* associative thickening stabilization, depletion stabilization or depletion flocculation may occur.
Get PriceDepletion flocculation, induced in dispersions of hydrophobic silica particles in nonpolar media by the presence of binary mixtures of nonadsorbing polymers, has been investigated both experimentally and theoretically. The binary mixtures used were either similar polymers having different molecular weights or mixtures of chemically different polymers.
Get PriceDepletion flocculation is a wellknown instability mechanism that can occur in oilinwater emulsions when the concentration of nonadsorbed polysaccharide exceeds a certain level. This critical flocculation concentration
Get PriceA depletion force is an effective attractive force that arises between large colloidal particles that are suspended in a dilute solution of depletants, which are smaller solutes that are preferentially excluded from the vicinity of the large particles. One of the earliest reports of depletion forces that lead to particle coagulation is that of Bondy, who observed the separation or 'creaming' of rubber latex upon addition .
Get PriceThe flocculation was reversible to dilution and weak shear forces and was attributed to polymer depletion. The results correlated well with predictions from potentialenergy calculations incorporating van der Waals, electrostatic, steric and depletion terms.
Get PriceOvercoming Depletion Flocculation Flocculation and sedimentation are the two most common symptoms of formulation instability. Certain conditions, such as high betaine levels, high electrolyte levels or the presence of cationic ingredients, can pose additional stability challenges in a formulation.
Get PriceThe viscosity results showed that CMC colors have less tenacious flocculation properties as compared to PVA colors. For CMC as a cobinder, CMC molecules remaining in the aqueous phase flocculate the pigment via a depletion flocculation mechanism. The depletion flocculation by CMC was more evident in platy clay coating colors. ACKNOWLEDGMENTS
Get Priceflocculation [flok″ula´shun] the formation of a precipitate or agglomerate in the form of downy tufts or floccules. flocculation test any serologic test in which flocculation takes place; usually applied to a variant form of the precipitin reaction. floc·cu·la·tion (flok'yūlā'shŭn), Do not confuse this word with floccillation. Precipitation ...
Get PriceThe purpose of coagulation and flocculation is to remove particulate impurities, especially nonsettleable solids and colour from the water being treated. Nonsettleable particles in water are removed by the use of coagulating chemicals. In the coagulation process, chemicals are added which will
Get PriceSuspension Concentrates is a survey into the theory of the formulation and stabilization of suspensions, elaborating on the breaking of aggregates and agglomerates and the role of dispersing agents on flocculation and electrostatic and steric stabilization.
Get PriceDec 13, 2008· Abstract. Microbial flocculation is investigated as a separation technique for harvesting marine microalgae for the production of biodiesel. Organic carbon (acetate, glucose or glycerine) was used as substrate for the growth of flocculating microbes in situ. Under stress, due to nutrient depletion, these microbes produced extracellular polymeric...
Get PriceAs a result, significant colloidal forces arising from the nonadsorbed nanoparticles (, depletion and structural forces) were always observed in the measured forces, which complicated the data analysis and also caused significant scatter in the resulting hydrodynamic forces.
Get PriceApr 01, 2005· Depletion flocculation is more commonly encountered in coatings than bridging flocculation, due, in part, to the elevated surfactant concentrations in most commercial coatings. Because the dispersion behavior in systems thickened with associative polymers is complex, it would be useful to have a way to visualize the possibilities.
Get PriceFor colloidal systems with adsorbed polymer, the mechanisms governing stabilization and flocculation are defined by the critical overlap concentration, c*. Below c*, steric stabilization or bridging flocculation are viable mechanisms of adsorption, while above c* associative thickening stabilization, depletion stabilization or depletion flocculation may occur.
Get PriceIt is suggested that the depletion flocculation of the emulsion droplets, induced by the addition of xanthan, leads to the formation of a particle network and that it is the timedependent yield ...
Get PriceFlocculation by depletion and bridging was induced by addition of the polysaccharide carboxymethylcellulose (CMC) to emulsions that were stabilised by lactoglobulin ( .
Get PriceApr 20, 2012· Water Treatment | Coagulation Flocculation Basics Duration: 3:52. American Water College 47,812 views. 3:52. Melting Aluminum Cans At Home Easy DIY Recycling Process .
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Get PriceThe colloidal interactions of associative polymers and latexes in the presence of surfactant are complex. This is because, in addition to good particle dispersion, both bridging and depletion flocculation can occur. Therefore, we have developed phase diagrams to help visualize these interactions.
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Get PriceMay 12, 2000· Additionally, the influence of the dextran solution over the colloidal stability of the microgel particles has also been studied by turbidimetry. The results show that the extent of deswelling increases with an increase in the dextran concentration in the range where flocculation by depletion is absent. Finally, depletion flocculation is detected.
Get Pricesystems (2). The initially stable colloidal sus pension started to undergo flocculation upon the addition of polymers to the solution when the polymeric density was above some value c* (depletion flocculation) and the floccula tion rate of the colloidal particles peaked at some higher polymeric density c*** > c*.
Get PriceThe effect of addition of free polymer to sterically stabilised dispersions, depletion flocculation, was investigated using rheological measurements.
Get Pricetions, depletion interactions induced by polymers added in storage or preparation may generate either desired structures 14 or deleterious aggregation 15 in products.
Get PricePoly(ethylene oxide) (PEO) and poly(vinyl pyrolidone) (PVP) induce different changes in the colloid stability of nanoparticles
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