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2014
|
vol. 61
|
issue 2
201-203
EN
The aim of this study was to determine the possibility of using gas chromatography to measurement of the acrylamide concentration in sewage sludge. Acrylamide, as a toxic substance, is not indifferent to human health, but it is used in the production of plastics, dyes, adhesives, cosmetics, mortar, as well as a coagulant for water treatment, wastewater or sewage sludge conditioning. Determination of acrylamide by gas chromatography was based on standard: EPA Method 8032A "Acrylamid by gas chromatography." It consists of a bromination reaction of the compound in the presence of dibromopropendial derivative, a triple extraction with the ethyl acetate, a concentration of the eluate sample up to the 1 ml volume, and an analysis by the gas chromatography using an electron capture detector (ECD). The acrylamide concentration of was calculated according to the formula presented in the mentioned standard. All samples were performed twice (the difference between the results was not greater than 10%), and the average value of the four samples was 17.64 µg/L−1. The presence of acrylamide in sewage sludge has been confirmed.
EN
The binary and ternary complex formations of poly(methyl vinyl ether-co-maleic anhydride) (PMVEMA) with copper ions and with bovine serum albumin (BSA) in the presence of copper ions in phosphate buffer solution at pH = 7 were examined by the techniques of UV-visible, fluorescence, dynamic light scattering, atomic force microscopy measurements. In the formation of binary complexes of PMVEMA-Cu(II), the addition of copper ions to the solution of PMVEMA in phosphate buffer solution at pH = 7 forms homogeneous solutions when the molar ratio of Cu(II)/MVEMA is 0.5. Then the formations of ternary complexes of PMVEMA-Cu(II)-BSA were examined. Study analysis revealed that the toxicities of polymer-metal and polymer-metal-protein mixture solutions depend on the nature and ratio of components in mixtures.
EN
This work is focused on polyelectrolyte enhanced ultrafiltration as an effective heavy metal separation technique. Three types of effluents, containing Zn(II), Cu(II) and Ni(II) ions, were subjected to the separation process. Poly(sodium 4-styrenesulfonate) - PSSS, a water soluble anionic polyelectrolyte was used as a metal binding agent. Two Sepa® CF (Osmonics) membranes: EW, made of polysulfone and a modified polyacrylonitrile membrane MW, were used in the ultrafiltration process. The preliminary UF tests were carried out on model solutions with target metal ion concentrations of 10, 100 and 250 mg dm-3. The main parameters affecting the metal retention (the polyelectrolyte quantity and solution pH) were examined. The values of pH 6 and polymer : metal concentration ratio CPSSS : CM = 7.5 : 1 (mol of mer unit per mol of metal) were selected to perform the galvanic wastewater ultrafiltration-concentration tests. Three types of wastewater containing Zn(II), Ni(II) and Cu(II) ions within the concentration range of 30÷70 mg dm-3 were used in the investigations. Very high metal retention coefficients, up to > 99%, were achieved. The retentates obtained were subjected to the decomplexation-ultrafiltration (pH = 1) and subsequent diafiltration step, which enabled partial recovery of concentrated metal ions and the polyelectrolyte. The recovered polyelectrolyte was reused toward Ni(II) ions and the high effectiveness of metal separation has been achieved.
PL
Zaprezentowano możliwość zastosowania ultrafiltracji wspomaganej działaniem polielektrolitu do separacji jonów metali z roztworów wodnych. Do badań wykorzystano roztwory modelowe o zawartości Zn(II), Cu(II) i Ni(II) w zakresie 10÷250 mg dm-3 oraz 3 rodzaje ścieków galwanicznych, z których każdy zawierał jeden z wymienionych jonów metali o stężeniu 30÷70 mg dm-3. Metale wiązano za pomocą poli(4-styrenosulfonianu sodu) - PSSS, co umożliwiało ich retencję na membranie ultrafiltracyjnej. Badania wstępne, wykonane na roztworach modelowych, miały na celu dobór głównych parametrów decydujących o efektywności procesu: stosunku stężeń polimer : metal oraz pH roztworu. Badania właściwe obejmowały ultrafiltracyjne zatężanie ścieków z zastosowaniem wybranych wartości stosunku stężeń polimer : metal (7,5 : 1) oraz pH (pH = 6). Uzyskano wysokie wartości współczynników retencji metali, powyżej 99%. Zatężone retentaty zakwaszono do pH = 1 w celu rozerwania połączeń polimer-metal oraz poddano kolejnemu procesowi ultrafiltracji z następującą po nim diafiltracją, co umożliwiło częściowy odzysk zatężonych metali oraz polielektrolitu. Zregenerowany polimer, po korekcie pH, został ponownie wykorzystany w procesie separacji jonów Ni(II), a obserwowane rezultaty nie odbiegały od wyników uzyskanych przy użyciu polimeru świeżego.
EN
Fifteen samples of silicone plates (PlateSi, area=12 cm2), with surfaces modified layer-by-layer with chitosan and unfractionated heparin, were obtained. The sample surfaces were pre-treated by cold oxygen plasma in a planar-type plasma chemical reactor with 50 W power before coating with layered polysaccharides. Pre-treatment was carried out in two alternative operation modes of the reactor, namely in the plasma etching mode and in the reactive-ion etching mode. Thromboresistance was assessed in vitro in contact with human blood. The thromboresistant silicon plates, modified layer-by-layer (3, 5, 7, and 9 bilayers) with chitosan, with molecular weights of 65 kDa, increased with the increase in the number of layers, up to 5. An increase in the duration of thromboresistance was observed in layer-by-layer modification of the surface of the plates with chitosan with a molecular weight of 200 kDa or with quaternized chitosan with a molecular weight of 200 kDa. Some samples of highly thromboresistant, modified PlateSi contributed to the adhesion of platelets and the haemolysis of red blood cells to a lesser extent than untreated silicon plates. The three most promising samples of modified PlateSi were selected.
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