Stability Of Oil In Water Emulsions Research Articles

Preparation, optimization, and testing of biostimulant formulations as stress management tools and foliar applications on brinjal and onion for growth and yield

Not only would the application of biostimulant formulations boost vegetable yields under typical and different biotic stress circumstances, but it will also be user and ecologically friendly. Due to their hydrophobic character and huge molecular volumes, the production of highly stable (~ 2 years shelf-life) emulsifiable concentrate (EC) formulations is the bottleneck of plant growth regulator uses. Gibberellic acid (0.25% EC) and Brassinolide (0.15% EC) were developed using a variety of solvents [solvent naphtha (C9), toluene, dimethyl sulfoxide] and surfactants (calcium alkylbenzene sulfonate, nonylphenol ethoxylate-13). Emulsification (spontaneous), detergency, and quick wetting performance were all outstanding in laboratory adjusted phytohormone formulations (E). Highly stable oil in water emulsions with exceptional compatibility (without phase separation) and outstanding emulsion stability (24 h) have been created using secondary alcohol ethoxylates and sulfonate anionic (5:5), which are affected by the hydrophilic-lipophilic balance (HLB) value (12.52) and type of nonionic and anionic surfactants. The hormone content fluctuation was also estimated to be appropriate using liquid chromatography–tandem mass spectrometry (LC–MS/MS) (5.0%). Single and double dosed applications of 450 and 900 mL ha−1 in brinjal (muktakeshi) and 180 and 360 mL ha−1 in onion (sukhsagar) have significantly improved growth and yields above control (untrated) plants. Gibberellic acid boosted brinjal yields by 37.5%, while Brassinolide raised onion yields by 33.9%. Plant growth regulator formulations that have been thoroughly developed and evaluated might be a big step toward environmentally friendly agricultural production.

A facile and economical configuration for continuous generation and separation of oil in water emulsions

The development of a facile, compact, and inexpensive system for continuous liquid-liquid emulsification and separation, is a major engineering challenge in different industries such as petroleum, cosmetics, and food production. Herein, we report a simple and scalable design strategy for continuous generation and separation of the oil in water emulsions. The inexpensive, abundantly available sand was utilized for the fabrication of porous beds connected to process piping for continuous emulsion generation and separation. A mechanistic understanding of the governing parameters such as sand wettability, pore size, retention time, and energy dissipation are discussed in detail. Building on this understanding, we are able to generate stable oil in water emulsions with either nanoparticles or surfactants and achieve their complete demulsification by tuning the sand wettability, pore size, and retention time. We show the industrial applicability of the designed system by generation and separation of extremely viscous heavy crude oil in water emulsion, which would be suitable for pipeline transportation. Our results show the new way for the development of a modular and economical process unit at the industrial scale for liquid-liquid emulsification and separation.

Hydrophobically modified xanthan: Thickening and surface active agent for highly stable oil in water emulsions

Oil-in-water (O/W) emulsions were prepared using exclusively a hydrophobically modified xanthan (HMX) under ordered conformation without any surfactant. A series of HMX differing in grafting density were utilized at different concentrations. It was demonstrated that HMX stabilizes O/W emulsions where pristine xanthan do not. Indeed, in some cases, emulsions with HMX proved to be homogeneous and stable over months. Emulsions microstructure and rheological properties were investigated over time as a function of HMX concentration and grafting density in order to determine the mechanisms governing this efficient stability. The higher the HMX concentration is, the better the emulsions stability. However, unexpectedly, increasing the HMX grafting density leads to faster destabilization. The whole set of results demonstrate that the stability of the emulsions against coalescence and creaming is explained by partitioning of HMX molecules between bulk and interface, thus split between viscosifying the aqueous phase and stabilizing the interface.

Controlled microfluidic emulsification of oil in a clay nanofluid: Role of salt for Pickering stabilization

Research on emulsions is driven by their widespread use in different industries, such as food, cosmetic, pharmaceutical and oil recovery. Emulsions are stabilized by suitable surfactants, polymers, solid particles or a combination of them. Microfluidic emulsification is the process of droplet formation out of two or more liquids under strictly controlled conditions, without pre-emulsification step. Microfluidic technology offers a powerful tool for investigating the properties of emulsions themselves. In this work stable oil in water emulsions were formed with hydrophilic Laponite RD® nanoparticles adsorbed at the interface of the oil phase and aqueous clay nanofluid in a T junction microfluidic chip. Emulsion stability up to at least 40 days could be observed.

Quantification of Si in Silicone Oils by ICP-OES

A new simple and low cost method of quantification of trace amounts of silicon (Si) in silicone oils has been developed by combining the silicone emulsion and inductively coupled plasma optical emission spectroscopy (ICP-OES) analysis. Silicone oils that contained phenyl groups in the viscosity range from 20 to 1000 mPa.s formed stable oil in water emulsions in the presence of Tween 80 surfactant and methylisobutylketone (MIBK). The Si in the emulsions was further quantified by ICP-OES. The calibration was performed using spiked inorganic silicon standard in the emulsions and the method was verified by the standard reference material SRM1066a. The precision and accuracy of the emulsion method applied to three phenyl containing silicone oils and polydimethylsiloxane (PDMS) with low viscosity (10 cSt) were good and acceptable (RSD < 10 % and the error range <10 %) with the limits of detection (LOD) in the emulsion as 0.5 ppm Si. Compared to the Si determination by the direct organic solvent ICP-OES, this method is much more convenient, where a regular ICP-OES instrument can be directly used for the quantification of Si in the silicone oils obtained via extraction by organic solvents from plastics and other samples.

Biosurfactant Production by Marine Bacterial Isolates from the Venezuelan Atlantic Front

Our purpose was to detect, isolate and characterize tensioactive agents with or without emulsifying activity from marine bacterial strains present in seawater and sediment samples from the Venezuelan Atlantic Front. Biosurfactants found in cell-free supernatants from all cultures presented high surface activity as they were able to reduce the water surface tension from 72 dynes cm(-1) to values between 41.7 and 33.9 dynes cm(-1). However, high indirect CMC values were registered for the most of these compounds (51.4%-56.1% v/v). Culture supernatants from S3 and S29 strains showed highest emulsifying activity in the dispersion assay with diesel oil (absorbance 1.06 and 1.18, respectively), while supernatant from the S10 strain induced the most stable oil-in-water emulsions with 16° and 25°API crude oils. Only culture supernatant from S3 strain was able to produce stable oil-in water emulsions with diesel oil and both type of crude oils.

Production of fine emulsions at pilot scale for oil compounds encapsulation

Feasibility of producing, at pilot scale (5kg), stable oil in water emulsions with size of 1–2μm and 100–200nm was investigated in relation with the oil content of the emulsion (4%, 8% and 12%w/w) and with the composition of the aqueous phase.Sunflower oil was used as a model for oil-based compounds. Acacia gum (AG) was used as emulsifier and protective support in association with maltodextrin (MD) with DE 12 or 21 (weight ratio MD/AG=3/2). Emulsions, with 40%w/w dry matter (carriers and oil), were produced using first a high shear disperser (30min) leading to coarse emulsions (∼2μm) and then a high pressure homogeniser (4min recirculation) leading to sub-micron emulsions (∼200nm).Viscosity, size and size distribution of emulsions were found to be mainly governed by the aqueous phase viscosity. Maltodextrin DE 12 leading to more viscous aqueous phases was found to be more efficient for the production of finer emulsions. Whatever the composition, no oil oxidation was observed after processing and after 2weeks storage. After 3weeks, coarse emulsions presented two phases whilst the submicron ones were stable after more than 2months.

Production of Ethoxylated Fatty Acids Derived From Jatropha Non-Edible Oil As a Nonionic Fat-Liquoring Agent

Natural fatty derivatives (oleochemicals) have been used as intermediate materials in several industries replacing the harmful and expensive petrochemicals. Fatty ethoxylates are one of these natural fatty derivatives. In the present work Jatropha fatty acids were derived from the non edible Jatropha oil and used as the fat source precursor. The ethoxylation process was carried out on the derived fatty acids using a conventional cheap catalyst (K₂CO₃) in order to obtain economically and naturally valuable non-ionic surfactants. Ethoxylation reaction was proceeded using ethylene oxide gas in the presence of 1 or 2% K₂CO₃ catalyst at 120 and 145°C for 5, 8 and 12 hours. The prepared products were evaluated for their chemical and physical properties as well as its application as non- ionic fat-liquoring agents in leather industry. The obtained results showed that the number of ethylene oxide groups introduced in the fatty acids as well as their EO% increased as the temperature and time of the reaction increased. The highest ethoxylation number was obtained at 145°C for 8 hr. Also, the prepared ethoxylated products were found to be effective fat-liquors with high HLB values giving stable oil in water emulsions. The fat-liquored leather led to an improvement in its mechanical properties such as tensile strength and elongation at break. In addition, a significant enhancement in the texture of the treated leather by the prepared fat-liquors as indicated from the scanning electron microscope (SEM) images was observed.

Emulsification of Chemically Modified Vegetable Oils for Lubricant Use

AbstractOil in water emulsions of several vegetable oils were studied in order to prepare a useful lubrication fluid. Several previously uncharacterized systems were studied in this paper, including those made from epoxidized vegetable oils. A series of different surfactants were studied in order to obtain emulsions suitable for lubrication applications. The epoxidized oils were found to form stable oil in water emulsions using several different surfactant systems. Only the (4) lauryl ether dodecyl polyethoxylated nonionic surfactant and a modified palm stearin methoxy ester ethoxylate were able to stabilize ordinary soybean oil for 1 week under our test conditions. Overall, the best surfactants were those with an HLB value slightly above 9. The droplet size of emulsions made with surfactants formed submicron droplets, whereas only droplets of larger diameter were obtained when surfactants were not added. Most importantly, a lubrication study was performed showing that even a 1% emulsion of the vegetable oils used in this study can reduce friction nearly as well as using the base oil alone.

Power ultrasound in fatliquor preparation based on vegetable oil for leather application

In recent years, power ultrasound has taken a significant place in chemical and physical activities of the process industries as an effective and non-polluting method of activation. Oil in water emulsions known as fatliquors are used for the lubrication of tanned leather fibres to get softness and also to improve the strength properties. In the present study, ultrasound has been used as a tool for the preparation of fatliquor emulsion for application in leather fatliquoring process. An emulsion is a fine dispersion of one liquid in another liquid. Sulphation is one of the common methods followed to prepare fatliquor emulsion where sulphuric acid is used. In the conventional process, emulsifying agent is also added to increase the stability of oil in water emulsions. The emulsifying agents generally used are chemicals or metal soaps. The potential use of ultrasound in the preparation of stable oil in water emulsions dispensing with sulphation process and with the minimum use of emulsifying agent has been studied and reported in this paper. This process enjoys the benefit of less pollution load in the form of chemical entities. The studies included the effect of process parameters such as ultrasonic output power and amount of oil used. Fatliquor emulsion prepared using ultrasound has been applied in leather fatliquoring process and the strength properties of the leathers were assessed. Emulsion particle size, which is another important parameter for diffusion through leather, has been measured using Laser Diffraction Technique. The stability of the ultrasonically prepared fatliquor emulsion has been found to be good. The results indicate that ultrasound could be effectively utilized in the preparation of non-ionic fatliquor emulsion eliminating sulphuric acid and impart required properties in leather.

Stabilization of dodecylbenzene in water emulsions with nonionic emulsifiers

Stable oil in water emulsions were prepared containing between 60 and 80% (w/w) dodecylbenzene and between 3 and 6% (w/w) mixtures of tetradecyl polyoxyethylene alcohol and nonylphenyl polyoxyethylene alcohol. The detection of birefringence and measurements of the droplet size, rheological properties, critical micelle concentrations, and cross-sectional areas of the mixed molecules showed that the emulsifiers form a third phase in which their molar ratio is approximately 1 to 1.