The processes of creaming, flocculation, and coalescence are well demonstrated by taking an. Coalescence when the droplets of discontinuous phase bump into each other to form a larger droplet thus increasing the average particle size over time, it is known as coalescence which is a form of instability. Pdf modeling of combined creaming and flocculation in. Emulsions are commonly made of macrosized droplets dispersed in a continuous solvent. Cs964605 creaming and flocculation of oilinwater emulsions containing sodium caseinate eric dickinson,1 matt golding, and malcolm j. The critical flocculation concentration of calcium corresponded to a critical zeta potential in all but one of the systems. Emulsion stabilitymexperimental studies on simultaneous. Click download or read online button to get emulsions book now. Despite their emulsifying action, we here found, that these materials can be used, equally well, in breaking the emulsions. The process is exclusively reversible flocculation and is not accompanied by a change in droplet size. Robins and co 192 creaming and flocculation in emulsions containing polysaccharide workers 4,5 attributed the emulsion destabilization by xanthan gum to depletion flocculation since they found no evidence for adsorption of xanthan gum at the emulsion droplet surface.
Influence of flocculation on optical properties of emulsions. Emulsion stability and testing lls health cdmo lubrizol cdmo. The minimum fibril concentration for flocculation is two orders of magnitude higher for the short. The influence of droplet flocculation on the optical properties of 1 and 10 wt% oilinwater emulsions with and without dye was investigated. There are three kinds of processes that take place in the emulsion. Enhanced stabilization of emulsions due to surfactant. Lls health cdmo emulsion stability and testing from lls health, the leading cdmo experts.
Structure, stability and rheology of flocculated emulsions. The influence of droplet flocculation on the optical properties of 1 and 10 wt% oil. Chapter 2 thermodynamics of emulsion formation and breakdown application of the second law of thermodynamics for emulsion formation. This process refers to aggregation of the droplets without any change in primary droplet size. Therefore, this study of the demulsificationflocculation mechanism of oilwater emulsion in asp flooding produced water is of great importance. Stability and characterisation of emulsions in the presence of colloidal particles and surfactants by roman pichot a thesis submitted to the university of birmingham. Difference between flocculated and deflocculated suspension definition. Breakdown of the emulsion flocculation and coalescence emulsion droplets charge on droplets prevents close approach flocculation. Instead the individual droplets have a chance to combine into bigger clusters of the original particles and these clusters, with their larger volume, cream faster. A flocculated suspension is a suspension in which particles have undergone flocculation. Creaming and flocculation of oilinwater emulsions containing sodium caseinate. Suspended particles vary in source, charge, particle size, shape, and density. Thermodynamics of emulsion formation and breakdown. The influence of calcium ions on the electrophoretic properties of phospholipid stabilized emulsions containing various quantities of the sodium salts of oleic acid so, phosphatidic acid spa, phosphatidylinositol spi, and phosphatidylserine sps was examined.
In brownian floc culation, particles under brownian motion collide with each other and form larger par. Do not allow the temperature of the heating surface to exceed 212. Pdf chapter 8 theory of emulsion flocculation researchgate. Stability loss in emulsions may occur in four different ways 27,28 creaming or sedimentation. Balance of energy and entropy and nonspontaneous formation of emulsions. Emulsion stabilitymtheoretical studies on simultaneous. Chapter formulation development of parenteral products. Coagulationflocculation process for produced water. In the case of an ow emulsion the oil droplets will. If all or part of the liquid of the internal phase separates and forms a distinct layer on the top or bottom of the emulsion as a result of the coalescing of the globules of the internal phase.
Flocculation occurs when the droplets stick to each other and form. Groundwater and surface water contain both dissolved and suspended particles. Stability loss in emulsions may occur in four different ways 27, 28 creaming or sedimentation. The theory of emulsion stability involving simultaneous flocculation and creanaing was discussed in detail in a previous paper 11. Systematic measurements of apparent viscosity as a function of shear stress or shearrate can be used to obtain information about the strength of attractive forces between flocculated droplets 23. Its a preference in the primary purification its a preference in the primary purification processes due. When present as the sole emulsifier, the milk protein ca mers. Flocculation stable emulsion coalescence or ostwald ripening gravitational separation phase separation. All of these products show typical colloidal instabilities creaming, sedimentation, flocculation, coalescence. Adsorption of surfactants at the liquidliquid interface. Petsev and others published mechanisms of emulsion flocculation find, read and cite all the research you need on researchgate. Emulsions formation, stability, industrial applications.
This breaks the emulsion, separating the asphalt from the water. Pdf creaming and flocculation of oilinwater emulsions. Flocculation of proteinstabilized oilinwater emulsions. The influence of charged lipids on the flocculation and.
Coagulation of an emulsion occurs in two stages, called flocculation and coalescence. Coagulation and flocculation are used to separate the suspended solids portion from the water. Emulsions encompass a vast number of everyday materials and products, including foodstuffs, personal care items, and pharmaceuticals. A systematic investigation into the influence of the wettability of spherical, nanometersized silica particles on the type and stability of water. Interaction energies forces between emulsion droplets and their combinations. Emulsion formation, stability, and rheology emulsion. Flocculation practical surfactants science prof steven. This will cause premature breakdown of the emulsion on the heating surface. Preparation and characterization of oilinwater and water.
Study on demulsificationflocculation mechanism of oil. Emulsion stability and testing introduction emulsions encompass a vast number of everyday materials and products, including foodstuffs, personal care items, and pharmaceuticals. Emulsion stabilitymtheoretical studies on simultaneous flocculation and creaming s. These systems are subject to two types of instabilities. Thus, i would like to talk about what is emulsion, what are the main characteristics of emulsions, what are the existing methods for preparations of emulsions and how to make simple emulsions. Flocculation, in the field of chemistry, is a process in which colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent.
Studies of creaming, flocculation and crystallisation in emulsions. Kralchevsky laboratory of thermodynamics and physicochemical hydrodynamics, faculty of chemistry, university of so. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. Flocculation and coalescence of micronsize emulsion droplets.
Flocculation is mainly observed in case of oil in water type of emulsions. The result will be two layers in the tank, neither of which will be suited for the intended use. Creaming and flocculation of oilinwater emulsions containing. Topical emulsions of both the oilinwater ow and waterinoil wo types are commonly used to improve properties such as aesthetics and ease of application, among. Importance of identification of major instability mechanisms every food emulsion is unique. Topical emulsions of both the oilinwater ow and waterinoil wo types are commonly used to improve properties such as aesthetics and ease of application, among others.
Flocculation of oilinwater emulsions by detergents. Click download or read online button to get emulsion formation and stability book now. The minimum required fibril concentration for flocculation was determined experimentally for fibril lengths of about 3 and 0. Pharmaceuticals, such as anesthetics of ow emulsions, lipid emulsions, double and multiple emulsions paints, such as emulsions of alkyd resins and latex emulsions drycleaning formulations. Flocculation was induced by addition of sds micelles to the aqueous phase of emulsions to increase the depletion attraction between droplets.
Flocculation and coalescence of oilinwarer emulsions. Stability of food emulsions 2 david julian mcclements biopolymers and colloids laboratory department of food science. Flocculation is assumed to occur according to the second order reaction. H is the enthalpy of the system and can be considered as the binding energy of the organic bulk material or the energy input needed to. Among other interesting results, those computations showed that it is possible to obtain a linear variation of the cube average radius of an emulsion as a result of flocculation and coalescence. Fogler department of chemical engineering, university. Emulsion products provide the most concentrated liquid flocculant with polymer concentrations of 2570%. This is attributed here to depletion flocculation by unadsorbed caseinate, probably in the form of small particles called casein submicelles.
One can debate whether these flocculated clusters will coalesce. Coagulation and flocculation process fundamentals 1 coagulation and flocculation. There is no single strategy that can be used to generally improve food emulsion stability. The conditions governing the flocculation of hydrocarbon or oil emulsions will depend on the nature of these emulsions. Filtering an emulsion is an operation which apply shear on it, and shear can destabilise the emulsion. Pdf mechanisms of emulsion flocculation researchgate. Beverage emulsions are very common on the market as they comprise all dairy based drinks and many of the soft drinks, which are diluted emulsions. The data were described well by the following equation. The research interest is preparation and characterization of oilinwater and waterinoil emulsions. Light microscopy has confirmed that the visually observable extent of reversible depletion flocculation in concentrated emulsions of this type is very sensitive to overall protein content.
Emulsion rheology provides a powerful indirect way of monitoring the nature and extent of flocculation in concentrated emulsions. Breakdown of the emulsion by flocculation and coalescence in the absence of an. Flocculation and coalescence of micronsize emulsion droplets ivan b. Emulsion formation and stability download ebook pdf. Moreover, it was found that the average radi us fluctuates up and down an average slope nazarzadeh. Doylea nanoemulsions are kinetically stable liquidinliquid dispersions with droplet sizes on the order of 100 nm. This site is like a library, use search box in the widget to get ebook that you want. Factors affecting the stability of emulsions stabilised by. Difference between flocculated and deflocculated suspension. This is unrealistic when it comes to real surfactantbased emulsions. The reversible flocculation induced by excess surfactant is studied. Rapid set emulsions are used with unreactive, low surface area aggregates. The influence of various negatively charged lipids on the stability of phospholipid stabilized oilinwater emulsions in the presence of varying concentrations of calcium chloride was examined by a measurement of the changes in the turbidity of the emulsion over time. Modeling of combined creaming and flocculation in emulsions.
Stability and characterisation of emulsions in the. In neat form, liquid emulsion flocculants range from to 200 to cp at. Flocculation is the process where droplets in an emulsion are attracted to each other and form flocs without the rupture of the stabilising layer at the interface. Liquid emulsion flocculants are available in cationic, nonionic, and anionic charges.
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