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1

Diffusive properties of alginate biosorbents

Kwiatkowska-Marks Sylwia, Miłek Justyna

Ecological Chemistry and Engineering. S

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2019

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Vol. 26, nr 1

149--163

EN

Effective diffusion coefficients for different heavy-metal salts: Cu, Cd, Zn, Cr, Pb in calcium alginate beads were determined. Their values depended on the metal type, anion from the metal salt, and the alginate content in the beads. The results of calculations indicate a decrease in the values of De, caused by an increase in the alginate content in the alginate sorbent beads. This is in agreement with the mechanism of the diffusion process taking place in porous carriers. Experimental data were found to be in good agreement with the mathematical model, as indicated by high values of the correlation coefficient.

2

Modelling of mass transport in watercourses at unsteady states

Bielski A.

Environment Protection Engineering

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2012

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Vol. 38, nr 3

159--173

EN

In terms of quality particularly difficult to describe are processes of mass exchange between different phases (e.g., atmospheric air-water, water-river sediment, water-algae, etc.). Whitman's model is most often used to describe the mass transport processes through the phase boundary. Theoretical analysis of the mass transfer process through the phase boundary showed that in unsteady states, the calculation results obtained from Whitman's model differ from the results obtained using the accurate diffusion model. These differences are due to the fact that concentration profiles in the direction of diffusion process change in time. Assumptions for Whitman's model do not include changes in the concentration distribution over time. Therefore, the correction factor was introduced to Whitman's model. The correction factor is defined as a parameter that multiplies a concentration derivative over time in the mass transport model. The correction factor can be used to estimate the effective diffusion coefficient of the substance that permeates from the aqueous phase to the sediment. The correction factor improves the degree of fit of the mass transport model to the measurement data. It can be used to estimate the effective turbulent diffusion coefficient from water phase to the sediment phase.

3

Wyznaczanie wartości współczynników dyfuzji efektywnej wybranych jonów w zestalonych strukturach mieszanin odpadów hutniczych i elektrowniach

Wolski P., Dąbrowska L., Płoszaj J.

Inżynieria i Ochrona Środowiska

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1998

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T. 1, nr 1

57-64

PL

Wyznaczono wartości współczynników dyfuzji efektywnej jonów wapniowych, potasowych, sodowych, glinowych, chlorkowych i chromu (VI), dyfundujących w zestalonych mieszaninach popiołów z dodatkiem hutniczych szlamów poneutralizacyjnych. Obliczone wartości współczynników dyfuzji zmieniały się od 6 × 10(-9) do 3 × 10(-12) m2/s. Najwyższe wartości uzyskano dla jonów sodu i potasu, najniższe dla wapnia. W celu uzyskania pełnego obrazu migracji jonów z podobnych struktur tworzonych na składowiskach stwierdzono konieczność kontynuowania badań w warunkach dynamicznego ługowania.

EN

Effective diffusion coefficients were investigated for ions Ca2+, K+, Na+, Al3+, Cl- and Cr(VI), which were diffusing within the solidified mixtures of ashes, with the addition of neutralization sludges. The values of diffusion coefficients varied from 6 × 10(-9) to 3 × 10(-12) m2/s, the highest being found for K+, Na+ cations, whereas the lowest for Ca2+. To get better insight in ions migration phenomena from similar structures in the dumping sites, it was recommended to carry out leaching experiments under the dynamic conditions.