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1
Content available Diffusion of Cd(II), Pb(II) and Zn(II) on calcium alginate beads
Kwiatkowska-Marks Sylwia, Miłek Justyna, Trawczyńska Ilona
Technical Sciences / University of Warmia and Mazury in Olsztyn
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2019
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nr 22(1)
19--34
EN
Effective diffusion coefficients (De) for different heavy-metal salts: Cd, Pb, Zn in calcium alginate beads were determined. Their values depend 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
Content available Uptake of copper ion using protonated dry alginate beads from dilute aqueous solutions
Aracena Alvaro, Álvarez César, Jerez Oscar, Guajardo Nadia
Physicochemical Problems of Mineral Processing
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2019
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Vol. 55, iss. 3
732--744
EN
This research aimed to identify the copper ion removal mechanism when using protonated dry alginate beads. This mechanism was explained through ion exchange between Cu ions and the protons from the functional groups of the alginate beads. Copper removal increased with stirring velocity, reaching values of 97.5 mg g-1 (97.5×10-3 kg/kg of PDAB) of dry alginate at 200 rev min-1, at a solution pH of 6.0 and a run time of 360 min. For the lowest level of copper concentrations, at 10 mg dm-3 (10×10-6 kg dm-3), full removal was attained. The removal kinetics was represented by a pseudo- first order model. A value of 0.0131 min-1 was found for the velocity constant. Under equilibrium conditions, the experiment data was fit to the Langmuir adsorption model, and the highest removal values were 270.3, 222.2 (222.2×10-3 kg/kg of PDAB) and 49 mg g-1 (49×10-3 kg/kg of PDAB) for pH values of 5.0, 3.5 and 2.5, respectively. These are higher than most sorbents used in the literature for copper removal. Increased temperature leads to higher Cu removal. The activation energy was calculated at 9.3 kJ mol-1 for the temperature range of 283 to 343K. Observations using SEM and composition measurements of the alginate cross-section taken by EDS showed a uniform distribution of the copper concentration through the structure of the alginate beads, independent of the solution pH, contact time and temperature.
3
Content available Recovery of cobalt ions from diluted solutions by means of protonated dry alginate beads
Aracena Alvaro, Padilla Sebastián, Jerez Oscar
Physicochemical Problems of Mineral Processing
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2019
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Vol. 55, iss. 5
1286--1297
EN
Mining effluents contain cobalt ions that can damage humans and flora. However, this meta also has high commercial value when recovered. The objective of this research work was to recover cobalt (Co2+) from diluted solutions using a biosorbent, specifically protonated dry alginate beads (PDAB). Experimental work was carried out in batch from an initial concentration of 22×10-6 kg dm-3 Co2+ and 80 mg alginate. Variables such as agitation, pH solution, experimental time, isotherm values, and temperature were analyzed. Maximum cobalt recoveries were obtained at pH values above 5.0, reaching 60.6×10-3 kg kg-1 of PDAB. Cobalt recovery occurred with ion exchange mechanisms from alginate carboxyl group proton release. Experimental data had excellent fit with both the Lagergren kinetic model (pseudo-first order) and the Langmuir isotherm model. As temperature increased, cobalt recovery increased. The calculated activation energy was 12.8 kJ mol-1. Compositional measurements obtained by scanning electron microscope and energy-dispersive X-ray spectroscopy for alginate crosssections showed uniform distributions of cobalt concentrations throughout the spherical alginate structure, independent of solution pH, contact time, or temperature. Furthermore, elution gave significant cobalt re-extraction (98.2%) and demonstrated PDAB reusability.
4
Content available Współczynnik spowolnienia dyfuzji soli metali ciężkich w granulkach alginianowych
Kwiatkowska-Marks S., Miłek J.
Inżynieria i Aparatura Chemiczna
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2017
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Nr 3
82--83
PL
Wyznaczono współczynniki spowolnienia dyfuzji w granulkach alginianu wapnia dla 9 różnych soli metali ciężkich: CuCl2, CuSO4, CdCl2, CdSO4, ZnCl2, ZnSO4, Zn(NO3)2, Pb(NO3)2, Cr(NO3)3. Wartość współczynnika spowolnienia dyfuzji zależała od rodzaj metalu (najlepsza dyfuzja dla CuCl2, a najniższe φ dla Cr(NO3)3), anionu soli metalu oraz zawartości alginianu w granulkach. Wzrost zawartości alginianu w granulkach prowadził do obniżenia wartości współczynnika spowolnienia dyfuzji. Obecność jonów siarczanowych znacząco obniżała wartość współczynnika spowolnienia dyfuzji soli tych metali w granulkach alginianowych. Najniższe współczynniki spowolnienia otrzymano dla wszystkich soli siarczanowych.
EN
Diffusion retardation coefficients for 9 different heavy metal salts in calcium alginate beads were determined. There were examined: CuCl2, CuSO4, CdCl2, CdSO4, ZnCl2, ZnSO4, Zn(NO3)2, Pb(NO3)2, Cr(NO3)3. Values of diffusion retardation coefficients depended on a metal type, anion from the metal salt, and the alginate content in beads. An increase in the alginate content in beads leads to a decrease of φ values. A presence of sulphate ions significantly decreased diffusion retardation coefficients in the beads. The lowest retardation coefficients were obtained for all sulphate salts.
5
Content available Wpływ anionu soli miedzi i kadmu na dyfuzję w granulkach alginianowych
Kwiatkowska-Marks S.
Inżynieria i Aparatura Chemiczna
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2017
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Nr 1
12--13
PL
Wyznaczono efektywne współczynniki dyfuzji w granulkach alginianu wapnia, dla siarczanów i chlorków dwóch metali ciężkich: miedzi oraz kadmu. Na wartość efektywnego współczynnika dyfuzji wpływały: rodzaj metalu, anion z soli metalu oraz zawartość ałginianu w granulkach. Współczynniki dyfuzji obliczono metodą konduktometryczną. Uzyskano dobrą zgodność danych doświadczalnych z modelem matematycznym, o czym świadczyły wysokie wartości współczynnika korelacji. Zarówno w przypadku soli miedzi, jak i kadmu obecność jonów siarczanowych znacząco obniżała wartość efektywnego współczynnika dyfuzji soli tych metali w granulkach alginianowych (w porównaniu do jonów chlorkowych).
EN
Effective diffusion coefficients in beads of calcium alginate for two heavy metals - copper and cadmium sulphates and ch lo rides were determined. The values o f these coefficients depended on the metal type, anion from the metal salt, and alginate content in the beads. The diffusion coefficients were calculated using the conductometric method. The experimental da ta were found to be in a good agreement with the mathematical model, confirmed by high values of the correlation coefficient. In both cases of copper and cadmium salts, a presence of sulphate ions significantly decreased the effective diffusion coefficient in the beads in comparison with chloride ions.
6
Content available Hydrożele alginianowe sieciowane jonowo i kowalencyjnie
Walczak J., Marchewka J., Laska J.
Engineering of Biomaterials
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2015
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Vol. 18, no. 132
17--23
PL
W niniejszej pracy zaprezentowano metodę otrzymywania mikrosfer hydrożelowych o podwyższonej wytrzymałości mechanicznej. Alginian sodu w formie mikrosfer hydrożelowych poddano sieciowaniu jonowemu i kowalencyjnemu. Sieciowanie przeprowadzono dwuetapowo. W pierwszym etapie alginian sodu usieciowano jonowo poprzez wymianę jednowartościowych kationów sodu na dwuwartościowe kationy wapnia. W zależności od stężenia chlorku wapnia otrzymano różne formy hydrożelu, od bezkształtnego żelu do gęstych aglomeratów mikrosfer. By uzyskać wyższą wytrzymałość mechaniczną jonowo usieciowanego hydrożelu, dodatkowo poddawano go reakcji z epichlorohydryną. Reakcja ta pozwoliła wprowadzić pomiędzy łańcuchy alginianu mostki kowalencyjne. Otrzymano również usieciowane mikrosfery alginianowe zmodyfikowane włóknami celulozy, które stanowiły dodatkowe wzmocnienie mechaniczne. Zbadano wpływ stopnia usieciowania na absorpcję wody przez suche próbki. Morfologię otrzymanych mikrosfer obserwowano za pomocą skaningowej mikroskopii elektronowej. Rozkład jonów wapnia w próbkach oceniono przy użyciu spektroskopii z dyspersją energii. Zbadano także degradację mikrosfer in vitro w płynie PBS.
EN
In this work a method of formation of hydrogel beads with increased mechanical durability is presented. Sodium alginate in the form of hydrogel beads was modified by ionic and covalent crosslinking. The crosslinking was achieved in two steps. In the first step, sodium alginate was ionically crosslinked by the ionic exchange of monovalent sodium cations with bivalent calcium cations. Different forms of the crosslinked alginate were obtained depending on the calcium chloride concentration. The forms varied from shapeless gel to hard agglomerated spheres. To increase mechanical durability of the ionically crosslinked alginate it was subjected to the reaction with epichlorohydrin. The reaction allowed to introduce covalent bridges between alginate chains. For additional reinforcement the crosslinked beads of alginate were modified with cellulose nanofibers. Dependence of water absorption in the dry samples on the crosslinking level was observed. Morphology of the beads was observed with the use of scanning electron microscopy. Calcium ions distribution in the samples was evaluated by energy dispersive spectroscopy analysis. In vitro degradation of the crosslinked alginates was also investigated.
7
Content available Hydrogels based on ionically and covalently crosslinked alginates
Walczak J., Marchewka J., Laska J.
Engineering of Biomaterials
|
2014
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Vol. 17, no. 128-129
109--110
EN
In the presented research sodium alginate modified by ionic and covalent crosslinking in the form of hydrogel beads was examined. In the first step, sodium alginate was ionically crosslinked by treatment with calcium chloride. Different forms of crosslinked alginate were obtained depending on the calcium chloride concentration. The forms varied from shapeless gel to dense agglomerated spheres. The optimal structure were spherical beads separated from each other. Ionically crosslinked alginates were then subjected to covalent crosslinking with epichlorohydrin. For additional reinforcement the crosslinked beads of alginate were modified with cellulose nanofibers. The products were compared in terms of water absorption in the dry samples, their morphology was observed by scanning electron microscopy. Calcium ions distribution in the composites was evaluated by energy dispersive spectroscopy analysis. In vitro biodegradation of the crosslinked alginates was also investigated.
8
Content available remote Biosorpcja metali ciężkich na granulkach alginianowych
Kwiatkowska-Marks S., Wójcik M. J., Kopiński L.
Przemysł Chemiczny
|
2011
|
T. 90, nr 10
1924-1930
9
Content available Determination of the effective diffusivity of cadmium(II) in calcium alginate beads
Kwiatkowska-Marks S., Wójcik M., Kopiński L.
Ars Separatoria Acta
|
2011
|
No. 8
11-23
EN
Effective diffusivity (De) of cadmium compounds was calculated in the beads. The study was carried out using two methods: a shrinking core model (SCM) method and a newly developed method named conductometric. It turned out to be a simple and effective method for the calculation of effective diffusivity of Cd(II) in alginate sorbents. The De values obtained by the two methods depended on the alginate content in the beads. However, SCM, in contrast to the conductometric method, gave De values increasing with increasing alginate levels in the beads and lower than the molecular diffusivity of Cd(II), this being inconsistent with the mechanism of diffusion in porous carriers. Hence, the conductometric method can be considered as one giving more reliable results, compared with the SCM method. Moreover, diffusion retardation coefficients for the alginate beads were calculated. Enhanced content of the biopolymer in the beads caused retardation of Cd(II) diffusion in the beads due to the decreasing calculated retardation coefficients with the increasing alginate contents in the beads.
10
Content available remote Electrostatic microencapsulation of living cells
Lewińska D., Bukowski J., Kożuchowski M., Kinasiewicz J., Weryński A.
Biocybernetics and Biomedical Engineering
|
2008
|
Vol. 28, no. 2
69-84
EN
Microencapsulation of different biologically active material for diverse applications have received increasing interest over the last 20 years. Microencapsulation of living cells seems to be a very promising and prospective technology, especially useful in biotechnology and medical applications. One of the most convenient and precise method for this purpose is an electrostatic technique. Electrostatic droplet generation could be performed using single- or multi-nozzle devices, significantly improving efficiency of the process. The usage of an impulse voltage generator allows to manufacture spherical and uniform microbeads with sizes from 0.2 to 3.0 mm of very narrow size distribution. Proposed two-liquid droplet electrostatic formation technique provides preparation of core/shell microbeads, where all cells are immobilized deeply inside a matrix and surrounded with cell-free polysaccharide layer. Such a solution prevents from cell protrusion out of the capsule. Applied electrostatic field is safe for encapsulated living cells and does not cause any cell dysfunction.
11
Wyznaczanie równowag sorpcyjnych dla sorpcji jonów Cu(II) przez granulki alginianowe
Kwiatkowska S., Wójcik M., Grubecki I.
Inżynieria Chemiczna i Procesowa
|
2001
|
T. 22, z. 3C
849--854
PL
Badano sorpcję jonów Cu(II) z rozcieńczonych roztworów wodnych przez granulki alginianowe. Wyznaczono izotermy równowagi dla szerokiego zakresu stężeń alginianów w granulkach. Stwierdzono, że równanie Langmuira dobrze opisywało dane doświadczalne, a stale równowagowe zależały od stężenia alginianu w granulkach.
EN
The sorption of Cu(II) ions from dilute aqueous solutions by alginate beads was studied. Equilibrium isotherms were determined for wide range of alginate concentrations in the beads. It was found that the Langmuir equation described the experimental data well and the equilibrium constants depended on concentration of alginate in the beads.
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