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Wyświetlanie 1-3 z 3
Tytuł:
Transport cząstek koloidalnych z zaadsorbowanymi jonami arsenu przez mineralne złoże porowate
Transport of colloidal particles with arsenic ions adsorbed on the colloidal surfaces through mineral porous bed
Autorzy:
Wróbel, I.
Polowczyk, I.
Sadowski, Z.
Powiązania:
https://bibliotekanauki.pl/articles/1819759.pdf
Data publikacji:
2009
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
jony arsenu
złoża mineralne
cząstki koloidalne
colloidal particles
arsenic ions
minerals
Opis:
Obecność odpadów przemysłowych w środowisku naturalnym staje się coraz bardziej zauważalnym problemem w ochronie środowiska. Za główne źródło ich powstawania, uważa się przemysł wydobywczy i przetwórstwa kopalin. W wyniku prowadzenia procesów wzbogacania, bądź procesów hutniczych, powstają odpady deponowane na hałdach, które w znaczący sposób przyczyniają się do zanieczyszczeń wód gruntowych. Dzieje się tak w wyniku transportu trudno rozpuszczalnych zanieczyszczeń przez naturalny polimineralny ośrodek porowaty. Zjawisko to zostało zaliczone do głównych procesów mających istotny wpływ na zanieczyszczanie wód gruntowych.
The storage of insecure industrial waste, descended from mining and metallurgical industry, has an influence on the pollution of a ground and groundwater. It is a result of migration of toxic substances into the bed of soli. The weathering processes and hydrodynamic changes in soil causes the colloidal particles formation, which are effective contaminations carriers through mineral porous media. In this paper transport of colloidal particles: synthetic hematite and natural kaolin has been investigated. The porous medias were waste from both Szklary and Złoty Stok heaps. The aim of this work is to inspect the influence of arsenate ions on the behaviour of colloidal particles in porous bed. The investigations were conducted in two ionic strengths: 5ź10-3 M KCl and 5ź10-4 M KCl, at pH 9.2-11.6. Results showed that transport of colloidal hematite was facilitated, when arsenic ions were adsorbed onto the colloid particles. Additionally, the increase of mobility of hematite was caused by a decrease of ionic strength. In the case of kaolin transport, the results showed an increase of kaolin particles migration without arsenic ions. These behaviour of colloidal kaolin particles into mineral bed isexplained by different surface property of kaolin particles. Results of examinations on colloidal particles of hematite and kaolin transport through column with mineral bed show, that examined mobility is conditioned with physico-chemical proprieties of colloidal particles and materials of porous bed. Studied colloids, can influence pollution of underground waters in the areas of storing of studied industrial wastes. Results of conducted measurements show, that the process of examined colloidal particles transport is influenced by presence of adsorbed arsenic ions. It is the most perceptible phenomenon in the case of the colloidal hematite, particularly for porous medium built from materials taken from the southern side of heap in Szklary and heap in Złot Stok. Additionally, influence of ion strength on quantity of transported colloidal particles through the layer of porous mineral medium was observed. When ion strength was decreasing, the thickness of the double electric layer increases on colloidal particles. It has impact on decrease of attracting interactions among particles of colloid, and also between colloidal particle and grain of mineral bed. The opposite case was noted during investigations on transportation of colloidal particles of kaolin. Adsorption of arsenic ions by particles of kaolin causes decrease of their mobility. This causes stopping of migration of arsenic ions to underground waters. The similar result is obtained when ion strength is enlarged.
Źródło:
Rocznik Ochrona Środowiska; 2009, Tom 11; 1119-1130
1506-218X
Pojawia się w:
Rocznik Ochrona Środowiska
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Detection of fibrinogen monolayers on mica by the colloid enhancement
Autorzy:
Nattich-Rak, M.
Adamczyk, Z.
Wasilewska, M.
Radziszewska, M.
Powiązania:
https://bibliotekanauki.pl/articles/363140.pdf
Data publikacji:
2011
Wydawca:
Uniwersytet Warmińsko-Mazurski w Olsztynie
Tematy:
adsorpcja lateksu
fibrynogen
koloidalne wzmocnienie warstw białkowych
monowarstwy fibrynogenu na mikach
adsorpcja nieodwracalna
cząstki koloidalne
adsorption of latex
fibrinogen
colloid enhancement of protein layers
fibrinogen monolayers by mica
irreversible adsorption
colloid particles
Opis:
Physicochemical properties of bovine plasma fibrinogen (Fb) in electrolyte solutions were characterised, comprising the diffusion coefficient (hydrodynamic radius), electrophoretic mobility (zeta potential) and the isoelectric point, found to be at pH=5.8. Similar electrokinetic measurements were performed for the mica substrate using the streaming potential cell. The kinetics of Fb adsorption on mica under diffusion-controlled transport was also studied. The surface concentration of Fb on mica was determined directly by AFM counting. By adjusting the time of adsorption, and bulk Fb concentration, monolayers of desired coverage were produced. It was confirmed that Fb adsorbed irreversibly on mica both at pH=3.5 and pH=7.4 (physiological value). It was postulated that in the latter case, where both the substrate and fibrinogen molecules were negatively charged, adsorption was due to heterogeneous charge distribution over the protein molecule. In order to check this hypothesis, monolayers of Fb on mica were studied using the colloid enhancement (CE) method, in which negatively and positively charged latex particles were used. Results of these experiments were quantitatively interpreted in terms of the fluctuation theory assuming that adsorption sites consisted of two and three Fb molecules, for pH=3.5 and 7.4, respectively. This allowed one to determine limits of applicability of the classical DLVO theory and confirm a heterogeneous charge distribution over the Fb molecule. It was also concluded that the CE method can be used for a sensitive determination of the Fb bulk concentration for the range inaccessible for other methods, i.e., for 0.1ppm and below. Another effect of vital significance confirmed in this work was that for some range of fibrinogen coverage both the negative and positive latexes efficiently adsorbed. This indicates the formation of superadsorbing surfaces having potential significance for various filtration processes.
Źródło:
Environmental Biotechnology; 2011, 7, 1; 1-11
1734-4964
Pojawia się w:
Environmental Biotechnology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of flow structure and colloidal forces on aggregation rate of small solid particles suspended in aqueous solutions
Autorzy:
Tyl, Grzegorz
Kondracki, Juliusz
Jasińska, Magdalena
Powiązania:
https://bibliotekanauki.pl/articles/2086810.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
aggregation
shear flow
DLVO
particles
colloidal forces
population balance
zbiór
przepływ ścinający
cząstki
siły koloidalne
bilans populacji
Opis:
In this paper aggregation of small solid particles in the perikinetic and orthokinetic regimes is considered. An aggregation kernel for colloidal particles is determined by solving the convection-diffusion equation for the pair probability function of the solid particles subject to simple shear and extensional flow patterns and DLVO potential field. Using the solution of the full model the applicability regions of simplified collision kernels from the literature are recognized and verified for a wide range of Péclet numbers. In the stable colloidal systems the assumption which considers only the flow pattern in a certain boundary layer around central particle results in a reasonable accuracy of the particle collision rate. However, when the influence of convective motion becomes more significant one should take into account the full flow field in a more rigorous manner and solve the convection-diffusion equation directly. Finally, the influence of flow pattern and process parameters on aggregation rate is discussed.
Źródło:
Chemical and Process Engineering; 2021, 42, 4; 369--389
0208-6425
2300-1925
Pojawia się w:
Chemical and Process Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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