Microemulsions: Components, Characteristics, Potentialities in Food Chemistry and Other Applications

Silva, José Dilson F. da; Silva, Yara P. da; Piatnicki, Clarisse Maria Sartori; Böckel, Wolmir José; Mendonça, Carla Rosane Barboza

doi:10.5935/0100-4042.20150135

Cited by 12 publications

(14 citation statements)

References 2 publications

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“…Based on the presented values, the CNS-E sample can be considered electrostatically stable due to the absolute value higher than 25mV, which cannot be inferred for the CNS-D and CNS-W samples due to the lower values observed [38]. This behavior for CNS-E occurred because ethanol acts as a co-surfactant, i.e., it is responsible for reducing the surface tension of the system, leading to the formation of a more stable interfacial layer and, consequently, increasing the stability of the solution [39]. This stability is related to electrostatic repulsion between the negative groups on the surface of the particles.…”

Section: Zeta Potential and Dynamic Light Scattering (Dls)mentioning

confidence: 94%

Variation of the milling conditions in the obtaining of nanocellulose from the paper sludge

2019

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This work aimed to evaluate three different milling conditions, seeking the optimization of CNS isolation process. The paper sludge was chemically treated with detergent and H 2 O 2, by two steps, to remove the noncellulosic contents (hemicellulose and lignin). After these treatments, the sample was milled with the variation of a liquid medium. The three liquids milling medium were: i) dry medium (CNS-D); ii) moist with water and (CNS-W) iii) moist with ethanol (CNS-E). The CNSs were characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), zeta potential and dynamic light scattering (DLS). The milled samples presented different behavior, depending on the medium applied. The CNS-W presented low efficiency due to the formation of agglomerates around the ceramic ball, resulting in larger fiber sizes (microsizes). Although, the samples CNS-D and CNS-E presented similar behavior of sizes distribution, with average size 340 nm and 373 nm, respectively, determined by DLS. The CNS-E sample presented higher yield and electrostatic stability in solution, besides not presenting loss of crystallinity, as occurred with CNS-D, observed by FTIR analysis. Thus, the isolation with ethanol showed more efficient process among the three processes studied. This work achieved the isolation of CNS; besides, it proposed an environmentally friendly isolation method, and this may add value in the paper sludge.

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Section: Zeta Potential and Dynamic Light Scattering (Dls)mentioning

confidence: 94%

Variation of the milling conditions in the obtaining of nanocellulose from the paper sludge

2019

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“…For techniques based on nebulization as sample introduction, a suitable sample preparation is need. Although several drawbacks of using dilution with organic solvents in spectrometric methods have been reported, this procedure is adopted in the standard methods and is quite used in the published works due to its simplicity and speed. , Emulsion/microemulsion sample preparation has been successfully used for fuel analysis − due to the homogeneous dispersion and stabilization of the oil microdroplets in the aqueous phase, which brings the viscosity close to that of an aqueous solution and reduces the organic load of the system. In addition, it allows using acids and inorganic standards for calibration thus increasing analyte stability …”

Section: Introductionmentioning

confidence: 99%

Determination of Iron, Copper, Zinc, Aluminum, and Chromium in Biodiesel by Flame Atomic Absorption Spectrometry Using a Microemulsion Preparation Method

et al. 2017

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This work proposes a flame atomic absorption spectrometry (FAAS) method for Fe, Cu, Zn, Al, and Cr determination in biodiesel using water in oil (w/o) microemulsion (ME) as a sample preparation method. A less toxic solvent (n-propanol), instead of those used in the standard method (ABNT NBR 15556), the absence of surfactant, and calibration using inorganic reference standards were investigated. A ternary phase diagram of biodiesel as oil, water, nitric acid, and n-propanol showed a single-phase ME region. The composition of ME adopted for analysis was 1.7 g of biodiesel and 1.1 mL of 1.4 mol L–1 HNO3, completed with n-propanol to 10 mL volume. Linear calibration graphs with R > 0.99 were obtained using ME prepared with oleic acid and inorganic standards. Analytes were stable for at least 3 days both in sample and in metallic standards MEs. The limits of detection obtained were 0.3, 0.1, 0.07, 1.7, and 1.0 mg kg–1 for Fe, Cu, Zn, Al, and Cr, respectively. These limits of detection were lower than those obtained by the reference method of dilution with organic solvent, due to lower fluctuation in the measurements. Recovery test values (93–105%) indicated absence of matrix effects. In order to assess the method accuracy, several real samples were analyzed by the proposed method, by the standard method, and also by acid digestion, without significant differences between results when applying the student’s t test. Relative standard deviations lower than 5% were obtained for standard and samples MEs. Therefore, combination of w/o ME with the FAAS technique and calibration with inorganic standards proved to be an accurate, simple, fast, and practical strategy, with greater analyte stability and appropriate sensitivity, so that the proposed method is suitable for biodiesel routine analysis.

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“…A extremidade hidrofílica dessa molécula é atraída pela água, enquanto que a parte hidrofóbica é atraída pelo óleo, ou seja, são substâncias caracterizadas pela presença em suas estruturas moleculares de duas regiões, uma polar e outra apolar (Silva et al, 2015), que possibilitam a interação entre meios que apresentem polaridades diferentes. Essa natureza atrativa dupla dos surfactantes os capacita a dispersar o óleo e a água.…”

Section: Solução De Surfactantesunclassified

Visualização Tridimensional Do Deslocamento De Óleo Por Suspensões De Microcápsulas Flexíveis Em Meios Porosos

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Microemulsions: Components, Characteristics, Potentialities in Food Chemistry and Other Applications

Cited by 12 publications

References 2 publications

Variation of the milling conditions in the obtaining of nanocellulose from the paper sludge

Variation of the milling conditions in the obtaining of nanocellulose from the paper sludge

Determination of Iron, Copper, Zinc, Aluminum, and Chromium in Biodiesel by Flame Atomic Absorption Spectrometry Using a Microemulsion Preparation Method

Visualização Tridimensional Do Deslocamento De Óleo Por Suspensões De Microcápsulas Flexíveis Em Meios Porosos

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