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Ocena opóźnienia migracji TCE w ośrodku porowatym na podstawie testów statystycznych

Kiecak A., Kret E., Malina G.

Przegląd Geologiczny

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2013

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Vol. 61, nr 1

62–-66

EN

Sorption is one of the most important processes responsible for contaminants migration in groundwater. The main aim of this study was to determine the retardation of TCE migration due to sorption in the Quaternary aquifer consisting mainly of medium to fine sands. Two types of the aquifer material, characterised by different grain-size distributions and similar organic matter contents were used for the batch tests. Soil samples came from a representative profile of the Nowa Dęba area - the site contaminated with chlorinated ethenes. The batch experiments allowed for determining the sorption isotherms, the partition coefficients K, between liquid and solid phases and, finally, the retardation coefficients R of TCE migration in groundwater in the porous aquifer.

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Determination of phase diagrams and thermoseparation behaviour of aqueous two-phase systems composed of ethylene oxide-propylene oxide random copolymer and potassium phosphate

Dembczyński R., Białas W., Jankowski T.

Chemical and Process Engineering

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2012

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Vol. 33, nr 3

411-429

EN

The application of aqueous two-phase systems (ATPS) is a cost-effective and simple method of protein separation (including enzymes) from complex systems. The first stage of designing the protein purification process in an ATPS involves the identification of the conditions for the formation of a given extraction system. For this purpose, the conditions for the formation of ATPSs in a thermoseparating EO50PO50 polymer/potassium phosphates system have been studied. Factors determining the ATPS formation comprised: separation temperature (4[degrees]C or 20[degrees]C), phosphate solution pH (6, 7.5 or 9) as well as the concentration of NaCl introduced into the systems (0.085 M, 0.475 M and 0.85 M). ATPS without NaCl were prepared as well. The conditions for the formation of the primary EO50PO50/potassium phosphate ATPS were determined with their phase diagrams. It was observed that with an increase of phosphate pH and NaCl concentration in the system, there was a decrease of the EO50PO50 and phosphate concentrations necessary to form a primary ATPS. After the primary two-phase separation, the top phase (rich in the EO50PO50 polymer) was partitioned from the bottom phase (rich in phosphates). Next, by means of polymer phase thermoseparation, a secondary two-phase system was formed. In the secondary EO50PO50/phosphate ATPS, the bottom phase was formed by the concentrated EO50PO50 polymer (30-80% concentration), while the top phase by a solution composed mainly of water, containing phosphate ions and remains of EO50PO50 polymer (3-7%).

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Application of the Partition Coefficient for Assessing Heavy Metals Mobility Within the Miasteczko Slaskie Zinc Smetler Impact Zone (Poland)

Diatta J., Wirth S., Chudzińska E.

Ecological Chemistry and Engineering. A

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2010

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Vol. 17, nr 9

1203-1212

EN

The present paper outlines some approaches, which were suggested for assessing heavy metals (Cu, Zn, Pb and Cd) mobility in soils contaminated by a zinc smelter activity. The concept was based on the assumption that partition coefficients, as ratios of total (assayed by aqua regia) metal contents to exchangeable (extracted by 1 mol CH3COONH4 dm–3 , pH 7.0) or to bioavailable (extracted by 0.1 mol NaNO3 dm–3) metal contents, will be more predictive in assessing metals mobility as compared with single extractions. The calculated partition coefficients for exchangeable and bioavailable metal forms were respectively termed Kd-Ex and Kd-Bio, which in turn were intended to represent the statico-dynamic nature of heavy metal mobility. It was found that metal mobility followed the sequence Cd > Zn > Pb > Cu, which implies that Cd and Zn will evoke more threat due to greater susceptibility for mobility. Regressions for the pairs logKd versus pH were applied in order to exhibit the proton generating capacity of each metal. The average calculated proton coefficient in the case of exchangeable metal forms amounted to 0.16 mole of protons released for each mole of Cu, Zn and Pb. In contrast, the proton coefficient for Cd was about 81 % greater. The estimation made on the basis of bioavailable metal forms showed, that Cd and Zn retention by soils generated, respectively 77 and 131 % more protons as compared to Pb. In terms of environmental concern, it may be formulated, that the higher the proton generating capacity, the highest the metal mobility, and thus the weakest partition to the solid phase.

PL

Praca przedstawia zagadnienia związane z oceną ruchliwości metali ciężkich (Cu, Zn, Pb, Cd) w glebach zanieczyszczonych w wyniku działalności huty cynku. Koncepcja opierała się na założeniu, że współczynniki podziału jako stosunki całkowitej zawartości metali (oznaczonej w wodzie królewskiej) do zawartości wymiennych (ekstrahowanych przez 1 mol CH3COONH4 dm-3 , pH 7.0) lub do zawartości biodostępnych (ekstrahowanych przez 0.10 mol NaNO3 dm-3 ) metali są bardziej przydatne do prognozowania ruchliwości metali ciężkich niż w przypadku pojedynczych ekstrakcji. Obliczone współczynniki podziału przyjęto odpowiednio jako Kd-Ex i Kd-Bio, które z kolej miały odzwierciedlić statyczno-dynamiczny charakter ruchliwości metali ciężkich. Uzyskane wyniki przedstawiają szereg Cd > Zn > Pb > Cu, z którego wynika, że Cd i Zn stanowią większe zagrożenie z uwagi na większą ich ruchliwość w glebie. Zależności między log Kd a pH wykorzystano w celu obliczenia zdolności każdego metalu do generowania jonów wodorowych. Średnie wartości obliczone dla wymiennych form metali wynosiły 0.16 mola protonów uwolnionych na każdy mol Cu, Zn i Pb w odróżnieniu od Cd, dla którego wartość ta była o 81 % większa. Oszacowanie dokonane na podstawie zawartości biodostępnych form metali ujawniło, że zatrzymywanie Cd i Zn przez gleby spowodowało generowanie odpowiednio o 77 i 131 % więcej protonów w porównaniu z Pb. Biorąc pod uwagę zagrożenie przyrodnicze, należy przyjąć, że im większa zdolność do generowania protonów, tym większą ruchliwość wykazuje dany metal i tym samym słabsze jest jego zatrzymywanie przez fazę stałą gleby.