The application of micellar systems has been growing during the last years because of their importance in various practical situations. Continued development of their application is necessary. If the principal economic interest of microemulsions is for some time enhanced oil recovery, the following also have significant applications such as pharmaceutical preparations, painting, and products for engine lubrication. The effect of variation in composition of anionic surfactants (α oleifin sulfonates) and the presence of a water-soluble charged polymer (Xanthan gum) and an uncharged polymer [poly (ethylene glycol)] on the phase behaviour of pseudo- ternary systems of water–oil surfactants was investigated. Several domains were observed when the composition of surfactants and cosurfactants (e.g., pentanol) in a mixture is varied. The appearance of these domains in the phase diagram has been attributed to the formation of different Winsor systems

Bensmaili, Aicha

Canselier, Jean-Paul

Moulai-Mostefa, Nadji

Nedjhioui, Mohamed

Skender, Abdelhak

English

Open Archive Toulouse Archive Ouverte

Presented at the EuroMed 2006 conference on Desalination Strategies in South Mediterranean Countries: Cooperationbetween Mediterranean Countries of Europe and the Southern Rim of the Mediterranean.  Sponsored by the EuropeanDesalination Society and the University of Montpellier II, Montpellier, France, 21–25 May 2006.Determination of micellar system behavior in the presenceof salt and water-soluble polymers using thephase diagram techniqueM. Nedjhiouia*, J.P. Canselierb, N. Moulai-Mostefaa, A. Bensmailic, A. SkenderaaInstitut Sciences de l’Ingénieur, Centre Universitaire Yahia Fares, 26001 Médéa, AlgérieTel. +213 (72) 401 404; Fax : +213 (25) 581 155; email: m_nedjioui@yahoo.frbLaboratoirede Génie Chimique, ENCIACET-INPT, BP 1301, F31106 Toulouse, FrancecFaculté de Génie Mécanique et de Génie des Procédés, USTHB, Alger, AlgérieAbstractThe application of micellar systems has been growing during the last years because of their importance in variouspractical situations. Continued development of their application is necessary. If the principal economic interest ofmicroemulsions is for some time enhanced oil recovery, the following also have significant applications such aspharmaceutical preparations, painting, and products for engine lubrication. The effect of variation in compositionof anionic surfactants (α oleifin sulfonates) and the presence of a water-soluble charged polymer (Xanthan gum) andan uncharged polymer [poly (ethylene glycol)] on the phase behaviour of pseudo- ternary systems of water–oilsurfactants was investigated. Several domains were observed when the composition of surfactants and cosurfactants(e.g., pentanol) in a mixture is varied. The appearance of these domains in the phase diagram has been attributed tothe formation of different Winsor systems.Keywords: Phase diagram; Anionic surfactant; Polymer; Phase behaviour; Microemulsion*Corresponding author.1. IntroductionThe study of micellar solution behaviour hasseveral uses in many fields such as chemistry,biochemistry, pharmaceuticals, and medicine aswell as in industry. The field of existence of thesemicellar systems is related to the nature of addi-tives and to their concentrations in the formula.Winsor [1] showed that these systems can pre-sent, on balance, four different states, bearing thisname (WI, WII, WIII, and WIV). Recently, aninterest in the incorporation of polymers in theformulation of microemulsions was developed inorder to improve the rheological properties. Theinfluence of solute and composition of themixtures on the phase boundaries [2,3] and on theorganization of surfactants in solution and at thesolid–liquid interface [4–6] has been well studied.In this work, we have varied the composition ofthe surfactant and investigated the effect of salt,the nature and the concentration of Xanthan gumand the poly- (ethylene glycol) on pseudo-ternarysystem behaviours by using the technique of thelayout of phase diagrams. To this end, we havefixed the essential objectives, the observation, theanalysis and the interpretations of the variousfields of existence of microemulsions and theirmodifications by adding salt and water-solublepolymers.2. Experiment2.1. MaterialsThe surfactants [α olefinesulfonates of sodium(AOS) with a general formula of R–(CH2)n–CH= CH2] are industrial products manufactured byWitco Chemical that have been the subject ofseveral works in enhanced oil recovery [7–9].Three types were considered: AOS in C12, C14and C16 with a purity of 37%. A high-puritygrade was purchased from Fluka and used asreceived. Poly(ethylene glycol) (PEG 1500) wassupplied from Sigma with a molecular weightaverage of 1500. Xanthan gum was purchasedfrom Rhodia (France); n-dodecane and n-pentanol(analytical grade) were purchased from Fluka.The salt, sodium chloride (99%), was purchasedfrom Prolabo.2.2. Preparation of mixturesInvestigations of systems containing threecomponents were made by using a geometricalrepresentation (technical squaring). With theintroduction of a fourth component to the system(cosurfactant, CS), the study of phase diagramsshould be done by using a geometrical repre-sentation in space. In general, it is more con-venient to be brought back to plane repre-sentations such as the triangular ternary diagramsknown as pseudo. One of the tops of the trianglethen represents the active mixture (MA = S+CS).The second top represents the aqueous phase (W).The last top consists of oil (O). It was shown[7,9] that a report/ratio CS/S = 2.5 gives betterresults. This report/ratio was maintained constantin this study.3. Results3.1. C12–dodecane–water systemFig. 1 shows the phase diagram of a ternarysystem containing C12–dodecane–water. It pre-sents a biphasic area (WII) located at the bottomof the diagram. The studied system contains twophases: overcome aqueous phases of micro-emulsion. This figure also presents a monophasicfield (WIV). This field indicates that there is totalmiscibility of the three compounds present in oursystem.3.2. C14–dodecane–water systemFig. 2 gives the same interpretations as in thecase of Fig.1, but with two differences. Themonophasic area (WIV) presents a small reduc-Fig. 1. Phase diagram of water/n-dodecane/MA system.Fig. 2. Phase diagram of AOS (C14)–water–MA system.tion; on the other hand, the diphasic area (WII)does not present a significant modification.3.3. C16–dodecane–water systemThe study of the areas presented in Fig. 3show that the monophasic field is wider than thatobtained in the case of the first two surfactants(C12 and C14). This figure also reveals the exis-tence of a small gelatinous field broader (WIV).The field gives a solubilization of the systemcompounds.Fig. 3. Phase diagram of AOS(C16)–water–MA system.4. DiscussionBy examining the three studied systems, wecan conclude that the diagrams take the sameforms and the same presentations with smallmodifications. However, the AOS in C12 presentsthe desired broader monophasic field (WIV). Thisfield gives a solubilization of the compounds ofthe system.4.1. Influence of salinityThe influence of salinity on the modificationof different field in the phase diagrams was madein the presence of AOS in C12 for a ratio ofCTA/TA = 2.5. Fig. 4 shows the diagram withcontent of NaCl to 0.5%. In this case, mono-phasic, biphasic, and triphasic zones appear andare divided along the phase diagram. Thereduction in the field representing the biphasicsystem (WI) was noticed. Fig. 5 shows thediagram with a content of 2% NaCl. The triphasiczone localized in Fig. 4 disappears and a broadmonophasic field was observed which supposesthat the triphasic system passed to only one phase(solubilization of the compounds present).The addition of a salt to the ternary pseudosystem modifies the behaviour of this last in thedirection of the formation and of the widening ofFig. 4. Effect of NaCl (0.5%) on phase behavior.Fig. 5. Effect of NaCl (2%) on phase behavior.the monophasic field (WIV), i.e., the addition ofsalt allows a solubilization of the components. Inaddition, the formation of a gelatinous zone isconsidered.4.2. Influence of polymersIn the literature, two illustrations of the inter-action between polymers and surfactants areallowed. The first describes the interaction interms of association of surfactant with polymer inaqueous solution (that is favoured for polymers ofthe hydrophobic groups). The second describesthe introduction in terms of micellization of themolecules of surfactants on the chain of polymer.Fig. 6. Effect of poly(ethylene)glycol on phase behaviour.Fig. 7. Effect of Xanthan gum on phase behavior.The addition of a quantity of the PEG polymerto water modifies the behaviour of phases of themicroemulsion as shown in Fig. 6, which indi-cates a triphasic zone (WIII) in the vicinity of thefield at high values of concentrations of oil andfor very weak concentrations of active mixture(MA).It seems that the areas determined previouslyare influenced by the addition of polymers andthat the direction of this modification is not easyto determine. Also, we note the appearance of adisphasic area (WII) which comes to replace thepreviously given monophasic zone. In the case ofthe addition of Xanthan gum, we can observe inFig. 7 a triphasic zone that appears and a verybroad diphasic field (WII). The results obtainedwith Xanthan gum reveal triphasic and mono-phasic zones similar to the preceding diagrams;however, the direction of the modification ofphase diagrams is not specified.5. ConclusionsInvestigations of the effect of the hydrocarbonlength chain of surfactant showed that the AOS inC12 gives the best results. The layout of thepseudo-ternany diagrams with constant ratio andvariable salinities shows that these last influencethe behaviour of the phases. The introduction ofNaCl into the system gives a broad field ofexistence of microemulsions (WIII and WIV).Thus, the succession of the systems of WINSORI ÷ IV ÷ II or WI ÷ III ÷ II is made possibleunder the effect of a variation of salinity. Thesevariations are visible by plotting the phasediagrams. The introduction of polymers into thesystem shows a modification of the obtaineddiagrams.The layout of the diagrams of the ternary andpseudo-ternary systems gives a good approach ofbalances between phases and a later forecast ofsuch balances.References[1] P. Winsor, Trans. Faraday Soc,. 44 (1984) 376.[2] F. Testard and Th. Zemb, Solute effect on con-nectivity of water in oil microemulsion. Langmuir,16(2) (2000) 232.[3] K. Wang, G. Oradd, M. Almgren, T. Asakowa andB. Bergensthal, Phase behaviour and phase structureof a cationic fluorosurfactant in water. Langmuir,16(3) (2000) 1042.[4] L. Sahoo, J. Sarangi and P.K. Misra, Organization ofamphiphiles. Part 1: Evidence in favour of pre-micellar aggregates through fluorescence spectro-scopy. Bull. Chem. Soc., 75(3) (2002) 859.[5] L. Sahoo, P.K. Misra and P. Samosundaran,Organisation of amphiphiles. Part II: Surface activityof polyoxyethylated alkyl phenols at air–water inter-face. Ind. J. Chem., 41A (2002) 1402.[6] P.K. Misra and P. Samosundaran, Organisation ofamphiphiles. Part IV: A comparative study of theorientation of polyoxyethylated alkyl phenols at air–water and silica–water interface. J. Surf. Deterg., 7(2004) 373.[7] B.R. Voca, Properties of balance of systems con-taining α olefinesulfonates in relation to enhanced oilrecovery l, INPT, France, 1985.[8] M.R. Bavaria, B. Bazin and C. Noik, Surfactants forthe enhanced oil recovery, physic chemistry of α-olefinsulphonates Report/ratio IFP, Paris, 1987.[9] V. Castro, Preparation and analyzes α-olefine-sulfonates, INPT, France, 1986.

Organisation of amphiphiles. Part II: Surface activity of polyoxyethylated alkyl phenols at air–water interface.

Organisation of amphiphiles. Part IV: A comparative study of the orientation of polyoxyethylated alkyl phenols at air– water and silica–water interface.

Organization of amphiphiles. Part 1: Evidence in favour of premicellar aggregates through fluorescence spectroscopy.

Phase behaviour and phase structure of a cationic fluorosurfactant in water.

Preparation and analyzes α-olefinesulfonates, INPT,

Properties of balance of systems containing α olefinesulfonates in relation to enhanced oil recovery l, INPT,

Solute effect on connectivity of water in oil microemulsion.

Surfactants for the enhanced oil recovery, physic chemistry of α-olefinsulphonates Report/ratio IFP,

Trans. Faraday Soc,.

Determination of micellar system behavior in the presence

of salt and water-soluble polymers using the phase diagram technique

http://oatao.univ-toulouse.fr/1206/1/Nedjhioui_1206.pdf

Determination of micellar system behavior in the presence of salt and water-soluble polymers using the phase diagram technique

Abstract

Similar works

Full text

Available Versions

Open Archive Toulouse Archive Ouverte