Microemulsion Formation and Detergency with Oily Soil: V. Effects of Water Hardness and Builder

Abstract

In this study, the impact of water hardness and builder on the phase diagrams of motor oil microemulsions and the detergency of oil removal from a polyester/cotton blend was investigated. Water hardness and builder were found to have insignificant effects on the microemulsion phase diagram with motor oil. A mixed surfactant system of two parts C 14-15 (PO) 3 SO 4 Na, and 98 parts C 12-14 H 25-29 O(EO) 5 H of the total actives at 4% salinity was used to study the effect of water hardness and builders sodium tripolyphosphate (STPP) or ethylenediaminetetraacetic acid (EDTA) on detergency at 30°C at a total active concentration of 0.3%. This formulation is in the Winsor Type III microemulsion regime. The microemulsion-based formulation resulted in better detergency than a leading commercial liquid laundry detergent at all concentrations up to 0.5% actives. The microemulsion-based formulation showed a plateau in detergency at[80% oil removal above 0.1% actives. The total oil removal decreased with increasing water hardness while the interfacial tension increased. When hard water was used in laundering, the total oil removal improved with increasing concentrations of STPP or EDTA up to stoichiometric levels, with STPP being slightly more effective than EDTA on a molar basis. Even high builder concentration could not improve hard water detergency to that of soft water. A significant fraction of oil removal occurred in the rinse steps vs. the wash step. Increasing water hardness reduced this fractional oil removal in the rinse steps, but it was still over half of total oil removal at 1,000 ppm water hardness.

Partition of n‐Butanol Among Phases and Solubilization Ability of Winsor type III Microemulsions

“…Microemulsions are thermodynamically stable, isotropic, transparent, or translucent dispersions [1] of water and oil, surfactant, or co-surfactant, and have been used in various fields, such as decontamination of organics [2], tertiary oil recovery [3], microemulsion extraction [4,5], etc., due to their very low interfacial tension and outstanding solubilization ability [6]. Microemulsions can exist in different forms, among which Winsor type III (W-III) is a system with a bi-continuous microemulsion being in equilibrium with an excess water phase and an excess oleic phase [1].…”

“…In the calculation, the assumption that no alcohol was dissolved in the aqueous phases was used, which needed to be further verified. In the observation of the optimum formulation and for obtaining the solubilization ability of the W-III microemulsions, the height reading method was typically used [2,19], which omitted the dissolution of alcohol in the excess oil (EO) phase and the excess water (EW) phase.…”

“…The assumption that no alcohol dissolved in the aqueous phases in the treatment of the ''fish-like'' [26,27] phase diagram, along with the accuracy of the height reading method in obtaining the optimum formulation [2,19] will be checked in this work and the role of alcohol in the formation and solubilization of W-III microemulsions will be analyzed. To avoid the difficulties in measuring the surfactant concentration, the internal standard method of gas chromatography (ISM-GC) was selected for this work.…”

Evaluation of Detergency Using Artificially Soiled Multifiber Fabrics

“…For the purpose, the exact evaluation of detergency is necessary and hence well-defi ned model systems have been proposed to clarify the detergency mechanism [12][13][14][15][16][17][18][19] . However, conventional evaluating methods with artifi cially soiled fabrics are needed because the fabric has complicated geometrical structure [20][21][22][23][24][25][26][27][28] .…”

Tristearin bilayers: structure of the aqueous interface and stability in the presence of surfactants

“…2,11,12 In these lamellae the TAG molecules generally adopt one of two conformations, either the "tuning fork" (where the sn-1 and sn-3 chains-see Fig. 20,21 In addition, a recent study reported that the presence of nanodiamonds (NDs) alongside various surfactants could assist in the removal of crystallised lipid for both anionic and nonionic surfactants at low temperatures (15-25 C), especially in the case of the anionic surfactant sodium dodecylbenzene sulphonate (SDBS). Another possible conformation is the "trident", where all three acyl tails pack side by side, which while not predicted to be prevalent in bulk TAG crystals, could play an important role at hydrophilic-hydrophobic interfaces.…”