Emulsion stabilitymexperimental studies on simultaneous. Breakdown of the emulsion by flocculation and coalescence in the absence of an. 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. Stability loss in emulsions may occur in four different ways 27, 28 creaming or sedimentation. This is attributed here to depletion flocculation by unadsorbed caseinate, probably in the form of small particles called casein submicelles. The theory of emulsion stability involving simultaneous flocculation and creanaing was discussed in detail in a previous paper 11. The influence of droplet flocculation on the optical properties of 1 and 10 wt% oilinwater emulsions with and without dye was investigated. The data were described well by the following equation. The critical flocculation concentration of calcium corresponded to a critical zeta potential in all but one of the systems. 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. Pdf creaming and flocculation of oilinwater emulsions. Filtering an emulsion is an operation which apply shear on it, and shear can destabilise the emulsion. Emulsion formation and stability download ebook pdf. 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.
When present as the sole emulsifier, the milk protein ca mers. The conditions governing the flocculation of hydrocarbon or oil emulsions will depend on the nature of these emulsions. Cs964605 creaming and flocculation of oilinwater emulsions containing sodium caseinate eric dickinson,1 matt golding, and malcolm j. Fogler department of chemical engineering, university. 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. Stability loss in emulsions may occur in four different ways 27,28 creaming or sedimentation. Flocculation was induced by addition of sds micelles to the aqueous phase of emulsions to increase the depletion attraction between droplets. This breaks the emulsion, separating the asphalt from the water. Pdf mechanisms of emulsion flocculation researchgate.
Lls health cdmo emulsion stability and testing from lls health, the leading cdmo experts. In neat form, liquid emulsion flocculants range from to 200 to cp at. The reversible flocculation induced by excess surfactant is studied. The minimum fibril concentration for flocculation is two orders of magnitude higher for the short.
The process is exclusively reversible flocculation and is not accompanied by a change in droplet size. 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. There are three kinds of processes that take place in the emulsion. Pdf chapter 8 theory of emulsion flocculation researchgate. Flocculation occurs when the droplets stick to each other and form. The influence of charged lipids on the flocculation and. Emulsions are commonly made of macrosized droplets dispersed in a continuous solvent. Structure, stability and rheology of flocculated emulsions. Emulsions formation, stability, industrial applications.
Chapter formulation development of parenteral products. Rapid set emulsions are used with unreactive, low surface area aggregates. Liquid emulsion flocculants are available in cationic, nonionic, and anionic charges. Pdf modeling of combined creaming and flocculation in. The processes of creaming, flocculation, and coalescence are well demonstrated by taking an.
A flocculated suspension is a suspension in which particles have undergone flocculation. 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. Difference between flocculated and deflocculated suspension. Chapter 2 thermodynamics of emulsion formation and breakdown application of the second law of thermodynamics for emulsion formation. Influence of flocculation on optical properties of emulsions. 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. This process refers to aggregation of the droplets without any change in primary droplet size. 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. One can debate whether these flocculated clusters will coalesce. 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. Emulsion stability and testing introduction emulsions encompass a vast number of everyday materials and products, including foodstuffs, personal care items, and pharmaceuticals. 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. Interaction energies forces between emulsion droplets and their combinations. Modeling of combined creaming and flocculation in emulsions.
Click download or read online button to get emulsions book now. 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. Emulsion formation, stability, and rheology emulsion. Thermodynamics of emulsion formation and breakdown. In brownian floc culation, particles under brownian motion collide with each other and form larger par.
Flocculation practical surfactants science prof steven. 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. The research interest is preparation and characterization of oilinwater and waterinoil emulsions. All of these products show typical colloidal instabilities creaming, sedimentation, flocculation, coalescence. Emulsion stability and testing lls health cdmo lubrizol cdmo.
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 and coalescence of micronsize emulsion droplets. Its a preference in the primary purification its a preference in the primary purification processes due. Despite their emulsifying action, we here found, that these materials can be used, equally well, in breaking the emulsions. The influence of droplet flocculation on the optical properties of 1 and 10 wt% oil. The minimum required fibril concentration for flocculation was determined experimentally for fibril lengths of about 3 and 0. Creaming and flocculation of oilinwater emulsions containing. Do not allow the temperature of the heating surface to exceed 212. 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. Importance of emulsions in various industrial applications. Influence of particle wettability on the type and stability of surfactantfree emulsions langmuir. Stability of food emulsions 2 david julian mcclements biopolymers and colloids laboratory department of food science. 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.
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. Stability and characterisation of emulsions in the presence of colloidal particles and surfactants by roman pichot a thesis submitted to the university of birmingham. 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. Coagulation of an emulsion occurs in two stages, called flocculation and coalescence. Moreover, it was found that the average radi us fluctuates up and down an average slope nazarzadeh. A systematic investigation into the influence of the wettability of spherical, nanometersized silica particles on the type and stability of water.
Coagulationflocculation process for produced water. Balance of energy and entropy and nonspontaneous formation of emulsions. Enhanced stabilization of emulsions due to surfactant. In the case of an ow emulsion the oil droplets will. Groundwater and surface water contain both dissolved and suspended particles. Flocculation is assumed to occur according to the second order reaction. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. Study on demulsificationflocculation mechanism of oil. Flocculation of oilinwater emulsions by detergents. Suspended particles vary in source, charge, particle size, shape, and density. This site is like a library, use search box in the widget to get ebook that you want. Kralchevsky laboratory of thermodynamics and physicochemical hydrodynamics, faculty of chemistry, university of so. Creaming and flocculation of oilinwater emulsions containing sodium caseinate.
Breakdown of the emulsion flocculation and coalescence emulsion droplets charge on droplets prevents close approach flocculation. Difference between flocculated and deflocculated suspension definition. Flocculation and coalescence of oilinwarer emulsions. Preparation and characterization of oilinwater and water.
This will cause premature breakdown of the emulsion on the heating surface. Flocculation stable emulsion coalescence or ostwald ripening gravitational separation phase separation. Flocculation is mainly observed in case of oil in water type of emulsions. Emulsion rheology provides a powerful indirect way of monitoring the nature and extent of flocculation in concentrated emulsions. Coagulation and flocculation are used to separate the suspended solids portion from the water. Flocculation and coalescence of micronsize emulsion droplets ivan b. These systems are subject to two types of instabilities. Factors affecting the stability of emulsions stabilised by. Emulsions encompass a vast number of everyday materials and products, including foodstuffs, personal care items, and pharmaceuticals. Emulsion stabilitymtheoretical studies on simultaneous. Emulsion products provide the most concentrated liquid flocculant with polymer concentrations of 2570%. Importance of identification of major instability mechanisms every food emulsion is unique. Therefore, this study of the demulsificationflocculation mechanism of oilwater emulsion in asp flooding produced water is of great importance.
Coagulation and flocculation process fundamentals 1 coagulation and flocculation. Studies of creaming, flocculation and crystallisation in emulsions. Emulsion stabilitymtheoretical studies on simultaneous flocculation and creaming s. Doylea nanoemulsions are kinetically stable liquidinliquid dispersions with droplet sizes on the order of 100 nm. This is unrealistic when it comes to real surfactantbased emulsions. There is no single strategy that can be used to generally improve food emulsion stability. Detergents have long been used in the stabilization of emulsions 1,2 and these were found probably the most efficient emulsifiers 3, 4. 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.