Wyniki wyszukiwania - BazTech

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Nowe podejście do frakcjonowania cząstek koloidalnych za pomocą grawitacyjnego frakcjonowania w samonastawnym kanale przepływowym w trybie pełnego zubożenia

Szparaga A., Kowalikowski T., Buszewski B.

Przemysł Chemiczny

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2016

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T. 95, nr 4

838--842

PL

Przedstawiono wyniki eksperymentalnych badań separacji zawiesiny krzemionki o ściśle zdefiniowanej wielkości cząstek oraz osadów dennych pobranych z rzeki Wisły, zarówno podczas frakcjonowania krótko-, jak i długotrwałego. Frakcjonowanie przeprowadzono w nowo opracowanej, samonastawnej celce do frakcjonowania z podziałem strumienia, pracującej w trybie pełnego zubożenia. Analizy zebranych frakcji dokonano metodą dyfrakcji laserowej za pomocą analizatora wielkości cząstek. Uzyskano bardzo dobre rozdzielenie obu materiałów w trakcie frakcjonowania krótkotrwałego. Separacja znacząco obniżyła się w trakcie frakcjonowania po 24 h w wyniku sedymentacji cząstek w aparaturze.

EN

A SiO₂ suspension with a strictly defined particle size distribution and a sediment taken from the Vistula river were sepd. by short and long-term fractionations carried out in a newly developed self-adjustable split-flow thin cell fractionation system operating in the full depletion mode. The collected fractions were characterized by using a laser diffraction particle size analyzer. A very good sepn. of both materials during the short-term fractionation was achieved. The sepn. efficiency significantly decreased during the 24 h long fractionation because of sedimentation of particles in the app.

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Detection of fibrinogen monolayers on mica by the colloid enhancement

Nattich-Rak M., Adamczyk Z., Wasilewska M., Radziszewska M.

Environmental Biotechnology

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2011

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Vol. 7, No. 1

1-11

EN

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.

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Transport cząstek koloidalnych z zaadsorbowanymi jonami arsenu przez mineralne złoże porowate

Wróbel I., Polowczyk I., Sadowski Z.

Rocznik Ochrona Środowiska

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2009

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Tom 11

1119-1130

PL

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.

EN

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.