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1

Components and parameters of synthetic chalcocite surface tension and its wettability by aqueous solution of n-octyl-β-D-glucopyranoside

Jańczuk B., Zdziennicka A.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 1

19--30

EN

The measurements of advancing contact angle of water, glycerol, formamide, ethylene glycol, diiodomethane, α-bromonaphthalene, 1,2,3-tribromopropane and aqueous solution of n-octyl-β-D-glucopyranoside (OGP) on unoxidized and oxidized synthetic chalcocite at the temperatures equal to 293, 303 and 313 K were made. Using the obtained contact angle values of the pure liquids the components and parameters of the unoxidized and oxidized synthetic chalcocite surface tension were calculated. For this calculation, different methods based on the Young equation were applied. It follows that the surface tension of both forms of chalcocite does not practically depend on the temperature in the range from 293 to 313 K. Taking into account the calculated values of components and parameters of unoxidized and oxidized chalcocite surface tension their wettability by the aqueous solution of n-octyl-β-D-glucopyranoside was considered. It appeared that wettability of the unoxidized chalcocite by aqueous solution of OGP can be predicted on the basis of the chalcocite surface tension components and parameters.

2

Nowa koncepcja wykorzystania oleju rzepakowego jako paliwa do zasilania silników o zapłonie samoczynnym

Longwic R., Sander P., Górski K., Jańczuk B., Zdziennicka A., Szymczyk K.

TTS Technika Transportu Szynowego

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2013

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R. 20, nr 10

2877--2889, CD

PL

W artykule przedstawiono wstępne wyniki prac w zakresie nowej koncepcji wykorzystania oleju rzepakowego (OR) jako paliwa. Pokazano podstawowe różnice w zakresie własności fizykochemicznych dla oleju rzepakowego i napędowego. Omówiono teoretyczny wpływ własności fizykochemicznych paliwa na proces tworzenia mieszaniny palnej. Przeanalizowano możliwości modyfikacji własności fizykochemicznych oleju rzepakowego poprzez zastosowanie dodatków chemicznych w małych udziałach objętościowych w mieszaninie z OR.

EN

This paper presents preliminary results of work on the new concept of using rapeseed oil (OR) as fuel. Shows the basic differences in the physicochemical properties of rapeseed oil and diesel. Discusses the theoretical effect of physicochemical properties of fuel for the process of creating a combustible mixture. Analyzed the possibility of modifying the physicochemical properties of rapeseed oil by the use of chemical additives in small proportions by volume of OR.

3

Wpływ surfaktantów na zwilżalność ciał stałych ze szczególnym uwzględnieniem skóry ludzkiej

Harkot J., Jańczuk B.

Wiadomości Chemiczne

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2007

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[Z] 61, 9-10

707-731

EN

This paper reviews wetting phenomena in relation to different types of solids and human skin in the presence of surfactants. Wettability of solids by surfactants is important for many technological applications. The addition of surfactants is necessary to achieve a better wettability of a given solid. In the first part of this article the definition of a contact angle and an interfacial tension along with methods of their determination is presented. Next, a relationship between a liquid--air, a solid-air and a solid-liquid interfacial tensions and wettability of solids is shown. Three types of wetting are discussed in this work: a spreading wetting, an adhesional wetting, and an immersional wetting. Wettability forces of hard surface and powders are also described in this part of the article. In the third part of the article main aspects related to the solids critical surface tension of wetting are presented. Different problems of solids' wetting critical surface tension are described, since there is still no unambiguous method to determine this value. Later, based on the Lucassen-Reynolds equation we described the dependence between the adsorption of surfactants at the interfaces, mainly in a solid-water-air systems and wetting of solids, because they are both strongly related. From this equation the slope of a plot of ?LVcos? (adhesion tension) versus ?LV (surface tension) gives us the information about the surface concentration of the surfactant at water-air and a solid-water interfaces in a solid--water-air system including both non-polar (low-energy) and polar (high-energy) solids. We have also shown that in the case of hydrophobic solids, for several types of surfactants, there is a constant negative slope of ?LV cos?-?LV curve. However, for high-energy polar solids the positive slope of this curve is observed and there is no linear dependence between adhesional and surface tension. Thus, for a high energy solid-aqueous surfactant solution-air systems it is difficult to establish synonymous mutual relationships between the adsorption of surfactant at a solid-air, a solid-liquid and a liquid-air interfaces and wettability of high-energy hydrophilic solids. At the end we presented main problems dealing with wettability of human skin surface, which is the most important factor of the skin protective function. It minimizes water loose, prevents entry of a foreign matter and chemicals, and defines smoothness and elasticity of the skin. Surprisingly, this subject has received a little attention in the literature. The human skin surface, after the extraction of sebum (skin surface lipids) belongs to hydrophobic surfaces (low-energy) in terms of critical surface tension and polar and dispersion components of a free surface energy. El-Shimi and Goddard compared the skin surface with polymer surfaces such as polyvinylchloride, polytetrafluoroethylene and polyethylene, but we have to remember that the human skin is a living matter and in the presence of sebum becomes hydrophilic. In order to remove this fatty film from the skin surface cleansing products, which contain many various surfactants, are used. Good wetting and cleansing effects of such products depend on surfactants ability to adsorb on the skin surface and reduce an interfacial tension at water-skin interface in skin-water-air system.

4

Wpływ substancji powierzchniowo czynnych na zwilżalność niskoenergetycznych hydrofobowych ciał stałych

Jańczuk B., Szymczyk K., Wójcik W.

Wiadomości Chemiczne

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2005

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[Z] 59, 5-6

489--508

EN

The paper reviews the thermodynamic of the most important problems of wettability of a solid and correlation between adsorption of surface active agents at water-air, and solid-water interfaces and wettability of hydrophobic low-energy solids. Three types of wetting have been considered; spreading wetting, adhesional wetting and immersional wetting. The usefulness of the Good and Girifalco, Fowkes, Owens and Wendt, and van Oss et al. approaches to interfacial free energy of liquid- -liquid and solid-liquid for determination of work of spreading, immersion and adhesion is presented. The correlation between the work of spreading, immersion and adhesion and contact angle is also shown. On the basis of the contact angle the relationship between wettability of the solids and its surface free energy and surface tension of liquid is discussed. Zisman found for low-energy solids a straight linear relationship between cos<θ((θ is the contact angle) and surface tension of liquids or aqueous surfactant solutions. The extrapolation of this relationship to cosθ = 1 allows estimation of the liquid surface tension required to give a contact angle of zero degree, which Zisman described as the critical surface tension. However, in contrary to Zisman, Bergeman and van Voorst Vader, stated that there is straight linear relationship between the adhesional tension (γ1γ,cosθ) and surface tension, γ1γ, of aqueous solutions of several types of surface active agents (surfactants). Such relationship was also confirmed by other investigators, however, the different equations describing the wettability of the same solids than Bergeman and van Voorst Vader by aqueous solutions of surfactants has been suggested. A direct method to investigate relative adsorption at interfaces is described. The usefulness of Lucassen-Reynders equation derived from Young and Gibbs equations for the studies of the correlation between adsorption of the surface active agents at water-air and solid-water interfaces and wettability of low-energy hydrophobic solids is discussed. We proved that on the basis of the surface tension of low-energy hydrophobic solids, surface tension of aqueous solution of surfactants or their mixtures, and Fowkes approach to interfacial tension the wettability of low-energy hydrophobic solids can be predicted.

5

Teoretyczne aspekty zjawiska adhezji

Krasowska M., Jańczuk B., Wójcik W.

Wiadomości Chemiczne

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2003

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[Z] 57, 3-4

155--184

EN

This paper reviews the most important problems of interparticle interactions, which determine effectiveness of many technologies (such as: painting, printing, xerographing) and physical phenomenon (for example: flocculation, aggregation, agglomeration, coagulation and wetting). This paper presents an evolution of theoretical models of adhesion phenomena. Hertz at the end of XIX century investigated creation of the contact between two particles. He based his conclusion on mechanical side of phenomena only. This observation gave beginning for Griffith's testing, which elaborated theory of brittle fracture (1920). In this theory he coupled surface energy g and elasticity. At the thirties Bradley and Derjaguin presented independently adhesion induced deformation. Bradley based his investigation on expotential relationship interaction between two molecules. Derjaguin interpreted these phenomena with the aid of geometrical and thermodynamical analysis. The fifties there was a great development of trybology and fracture mechanics. Irwin introduced new technical term of strain energy G released when the crack area varied by dS. After that Krupp generalized Derjaguin model and added influence of plastic deformation. At the early seventies two theories were created. First theory created by Johnson, Kendall and Roberts (called JKR), and second one by Derjaguin, Muller, Toporow (called DMT theory). These two models were and still are base to interpreting interparticle interactions. The next model is Dugdale model developed for crack tip plasticity and is quite simple: the stresses in the cohesive zone are constant and equal to the yield stress of the testing material. In 1983 Muller assuming a Hertzian profile, compared his earlier thermodynamic method, in which the force of attraction decreases from 2πWA to πWA, for more correct value by summing up the interactions in the Hertzian fixed gap. In this publication range of application each of these theories are introduced.

6

Silica interparticles action in alkanes

Wójcik W., Jańczuk B., Ogonowski R.

Physicochemical Problems of Mineral Processing

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2002

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Vol. 36

279-288

EN

Measurements of the destruction time of the sediment column structure of silica particles were carried out for different fractions of silica particles in alkanes from decane to hexadecane. The authors studied the correlations between the measured destruction time of the silica particles sediment column structure and the bulk properties of silica particles and alkanes, as well as the alkane-air, silica particles-air and silica particles-alkane interfacial properties. On the basis of this study linear relationships between the reciprocal of the destruction time and the average diameter of the silica particles fractions, the work of alkanes cohesion, the alkanes density and the difference between the detachment and attachment forces were found. From these relationships, the critical values of the particle diameter, the cohesion work of the alkane density and the difference between the detachment and the attachment forces were determined. It was found that for the systems, having critical values of the parameters mentioned above, the detachment force is equal to the attachment force, both resulting from gravitational and interfacial interactions, respectively. It also results from the present study that the attachment force between silica particles depends on the work of alkane cohesion and the work of silica particle adhesion to liquid, and that destruction of silica particles sediment column structure takes place as a result of interruption of the alkane film between two silica particles. The changes of the destruction time as a function of the number of carbon atoms in the molecule of alkanes occurred as a result of the decreased detachment force and the perimeter of the contact plane and increased attachment force between silica particles in alkanes.

PL

W pracy przedstawiono wyniki pomiarów czasu niszczenia struktury słupka sedymentu ziaren krzemionki w węglowodorach alifatycznych od dekanu do heksadekanu. Pomiary te przeprowadzono w tzw. "rurce Waksmundzkiego" dla frakcji ziarnowych krzemionki, których średnie średnice wynoszą odpowiednio: 1,04 x 10-4 m, 1,35 x 10-4 m, 1,75 x 10-4 m i 2,25 x 10-4 m. Uzyskane rezultaty czasu niszczenia struktury słupka sedymentu ziaren krzemionki omówione zostały w zależności od objętościowych właściwości krzemionki i alkanów, jak również w zależności od międzyfazowych właściwości. Czas niszczenia struktury słupka sedymentu rośnie liniowo tylko ze wzrostem lepkości badanych alkanów, natomiast liniowe zmiany stwierdzone zostały dla zależności odwrotności czasu niszczenia struktury w funkcji średniej średnicy ziaren krzemionki, gęstości i pracy kohezji węglowodorów. Z tych liniowych zależności wyznaczona została krytyczna średnica ziaren, krytyczna gęstość i praca kohezji. W układach, w których jeden z parametrów ma krytyczną wartość, struktura słupka sedymentu jest trwała tzn. niemożliwe jest jej zniszczenie. Wówczas siły odrywu są równe siłom zlepienia. Zakładając, że ziarna krzemionki są kulkami obliczono siły odrywu, które nieznacznie maleją ze wzrostem długości łańcucha węglowodorowego alkanów. Wykorzystując wyznaczoną krytyczną wartość pracy kohezji, która praktycznie nie zależy od wielkości ziaren krzemionki, obliczono promień płaszczyzny kontaktu pomiędzy ziarnami krzemionki. Znając wielkość promienia płaszczyzny kontaktu obliczono siły zlepienia pomiędzy ziarnami krzemionki w alkanach. Siły zlepienia, w przeciwieństwie od siły odrywu, rosną ze wzrostem długości łańcucha węglowodorowego alkanów, w rezultacie różnica pomiędzy nimi maleje od 3,2 x 10-10 N/ziarno (10.7 mN/m) dla dekanu do zera dla węglowodoru o krytycznej pracy kohezji. Na podstawie liniowych zmian odwrotności czasu niszczenia struktury słupka sedymentu krzemionki w funkcji różnicy sił odrywu i zlepienia wyznaczono krytyczną wartość tej różnicy. Niewielkie ujemne wartości krytycznej średnicy świadczą, że energia filmu węglowodorowego pomiędzy ziarnami krzemionki jest nieco zwiększona przez swobodną energię powierzchniową krzemionki.

7

The effect of liquids on the interaction between coal particles

Ogonowski R., Wójcik W., Jańczuk B.

Physicochemical Problems of Mineral Processing

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2001

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Vol. 35

43-53

EN

Taking into account the published earlier values of the destruction time of the coal column structure formed from the four fractions of coal particles having the average diameter 1.5x10-4 m, 2.5x10-4 m, 3.5x10-4 m and 4.5x10-4 m in the homologous series of alkanes and alcohols, the correlation between destruction time and bulk properties of coal and liquids as well as the liquid-air, coal-air and coal-liquid interfacial properties was studied. On the basis of this study the linear relationship between the reciprocal destruction time and average diameter of the coal fractions, work of alkane and alcohol cohesion, their density, the difference between liquids and coal density, and free energy of interactions per one molecule of the liquid was found. From these relationships, the critical values of the particles diameter, work of cohesion, density, difference between coal and liquid density, and free energy of interactions for infinitely long destruction time were determined. It was stated that for systems having critical values of these parameters, the detachment force is equal to the attachment one. From study it also results that the attachment forces between coal particles depend on the work of cohesion of liquid and work of adhesion of coal to liquid, and that the destruction of the structure of the sediment column take place as a result of the interruption of the film of the liquid between two coal particles.

PL

Wykorzystując opublikowane wartości czasu destrukcji struktury słupka sedymentu w rurce szklanej dla frakcji ziaren węgla o średniej średnicy 1.5x10-4m, 2.5x10-4m, 3.5x10-4m i 4.5x10-4m, w węglowodorach od heksanu do heksadekanu i alkoholach od metanolu do dekanolu, przeprowadzono badania nad korelacją pomiędzy czasem destrukcji a właściwościami objętościowymi badanych cieczy i węgla oraz międzyfazowymi ciecz-powietrze, węgiel-powietrze i węgiel-ciecz. Na podstawie przeprowadzonych badań stwierdzono, że czas destrukcji rośnie ze wzrostem długości łańcucha węglowodorowego alkanów i alkoholi a maleje ze wzrostem średniej średnicy ziaren węgla. Zmiany czasu destrukcji wynikają z różnicy pomiędzy siłami odrywającymi ziarno węgla od ziarna węgla a siłami adhezyjnymi (zlepienia), które odpowiednio zależą od oddziaływań grawitacyjnych i międzyfazowych. Obliczone siły odrywające, przy założeniu, że ziarna węgla są kulkami, maleją ze wzrostem długości łańcucha węglowodorowego badanych cieczy. Dla obu badanych szeregów homologicznych stwierdzono liniową zależność pomiędzy odwrotnością czasu destrukcji słupka sedymentu i średnią średnicą badanych frakcji ziaren węgla, pracą kohezji alkanów i alkoholi, ich gęstością, różnicą gęstości węgla i badanych cieczy oraz swobodną energią oddziaływań w przeliczeniu na jedną cząsteczkę cieczy. Prostoliniowe zależności pozwoliły na wyznaczenie tzw. „krytycznych wartości” takich parametrów jak: średnica ziaren, praca kohezji, gęstość, różnica gęstości i swobodna energia oddziaływań dla nieskończenie długiego czasu destrukcji (1/t=0). Dla układów o krytycznych wartościach wymienionych parametrów siły odrywania równe są siłom zlepienia. Biorąc to pod uwagę obliczono promień płaszczyzny kontaktu oraz wielkość sił zlepienia pomiędzy ziarnami węgla w badanych cieczach. Przeprowadzone obliczenia wykazały, że siły zlepienia pomiędzy ziarnami węgla są nieco wyższe od pracy kohezji badanej cieczy. Wynika z tego, że o wielkości sił zlepienia pomiędzy ziarnami węgla w badanych cieczach decyduje nie tylko wielkość pracy kohezji danej cieczy ale również wielkość pracy adhezji węgiel-badana ciecz. Ponieważ praca adhezji jest większa od pracy kohezji, zatem niszczenie struktury słupka sedymentu ziaren węgla zachodzi w wyniku przerwania ciekłego filmu pomiędzy dwoma ziarnami węgla.

8

Swobodna energia międzyfazowa a swobodna energia adsorpcji i micelizacji substancji powierzchniowo czynnych

Jańczuk B., Wójcik W., Zdziennicka A., Gonzalez-Martin M.A., Bruque J.M.

Wiadomości Chemiczne

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2000

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[Z] 54, 9-10

793-815

EN

This paper reviews the results of investigations of the surface free energy of surfactants and the correlation between hydrophobic group of surfactant-water and hydrophilic group of surfactant-water interfacial free energy and standard free energy of adsorption at water-air (oil) interface and standard free energy of micellization. The surface free energy of the hydrophobic and hydrophilic group of the surfactants is considered separately. The van Oss and co-workers' approach to the interfacial liquid-liquid and solid-liquid free energy used for the energy determination has been described. This approach treats the surface free energy of a solid and a liquid as the sum of the Lfshitz-van der Waals and Lewis acid-base components. The acid-base component of the surface free energy depends on the electron-acceptor and electron-donor parameters of this energy. Different determination ways of the surface free energy components and parameters of the hydrophobic and hydrophilic group of the surfactants are shown. The usefulness of the Young equation and adsorption data of n-alkanes on solid surface for determination of the Lifshitz-van der Waals component and electron-acceptor parameters of the acid-base component of the hydrophilic group of the surfactants is presented. On the basis of the surface free energy components and parameters of the hydrophobic and hydrophilic group of the surfactants and recently modified DLVO theory, the free energy of interaction between molecules or ions of the surfactants through the water phase and the free energy of removing surfactant molecules or ions from the water phase to air or oil phase can be predicted. The modified DLVO theory treats the interaction between molecules or particles through the liquid phase as the sum of Lifshitz-van der Waals, acid-base and electrostatic interaction components, which details are described for the systems including ionic or nonionic surfactants. The free energy of interaction can be used for prediction of the standard free energy of adsorption and micellization of the surfactants if the contactable area of the molecules or ions of the surfactants is known. Different ways of the contactable area between the hydrophobic and hydrophilic group of the surfactants and between groups and water molecules are presented. The calculated values of the free energy of interactions of the surfactants through water phase are compared to the standard free energy of micellization and the standard free energy of the adsorption of surfactants at water-air (oil) interface. For this purpose the determination of the standard free energy of adsorption from isotherms of adsorption of the surfactants and their standard free energy of micellization is also described.