Ion Exchange Properties of Alginate Fractions.

Haug, Arne; Gewitz, H.S.; Völker, Wolfgang; Hedén, C.‐G.; Malmgren, B.; Palmstierna, H.

doi:10.3891/acta.chem.scand.13-1250

Cited by 41 publications

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“…Ion uptake by alginate samples shows a definite preference for larger over smaller cations (i.e. Sr > Ca > Mg) Haug andSmidsrod 1965, 1967) but in this study it appears that the polymers appear to prefer the smaller Mgz+ cation to the larger Ca2 + cation, although the importance of size could be determined more conclusively by the analysis of strontium uptake. These results appear to hold whether the anionic nature of the polysaccharide was conferred by the presence of wglucuronic acid or pyruvate ketal groups.…”

Section: Single Dlvaient Ion Uptakementioning

confidence: 50%

Uptake of metals by bacterial polysaccharides

Geddie

Sutherland

1993

Journal of Applied Bacteriology

151

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J.L. GEDDIE AND I.W. SUTHERLAND. 1993. The binding of cations by a range of bacterial polysaccharides was examined. Comparison of native and deacetylated polymers indicated the influence of polysaccharide acetylation on ion uptake and selectivity. The effects of temperature and pH on ion uptake were also examined. Metal ion uptake was carried out by dialysis and samples were analysed using ion chromatography. The native acetylated polymers showed a selectivity for Ca2+ > Mg2+ > monovalent cations, whereas samples lacking acetyl groups showed a selectivity for monovalent cations > Mg2+ > Ca2+. Increased temperatures reduced the capacity for several of the polymers to bind the cations; The Zoogloea ramigera polymer appeared least affected. The pH value also affected uptake.

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Section: Single Dlvaient Ion Uptakementioning

confidence: 50%

Uptake of metals by bacterial polysaccharides

Geddie

Sutherland

1993

Journal of Applied Bacteriology

151

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“…This would correspond to scenarios where [Metal] , [Na] < 1000 mM. These Na concentrations are comparable to those employed in Haug's (19,43) study of the Na-Ca alginate ion-exchange system. The work described herein indicates that the reduction in cadmium sorption observed by Scheiwer and Volesky (11) likely represents a minimum because Na would compete more effectively for cadmium if the brown algal biomass contained alginate with significantly lower frequencies of G-blocks (or conversely, higher frequencies of M-blocks or MG-blocks, as is the case of un-fractionated Laminaria or bulk Macrocystis).…”

Section: ≡S-amentioning

confidence: 55%

Metal Selectivity of Sargassum spp. and Their Alginates in Relation to Their α-l-Guluronic Acid Content and Conformation

Davis

Llanes

Volesky

et al. 2002

Environ. Sci. Technol.

190

118

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The discovery of a consistent and unusual enrichment in homopolymeric alpha-L-guluronic acid G-blocks in alginates extracted from a suite of Sargassum brown algae is described in this study. 1H NMR spectroscopy was used to characterize these alginates which display homopolymeric guluronic acid block (G-block) frequency values (F(GG)) between 0.37 and 0.81. The presence of these G-blocks results in an enhanced selectivity for cadmium or calcium relative to monovalent ions such as sodium and the proton as well as smaller divalent ions such as magnesium. Results of competitive exchange experiments for the Cd-Ca-alginate system yield selectivity coefficient, K*(Cd)Ca, values between 0.43 +/- 0.10 and 1.32 +/- 0.02 for a range in F(GG) of 0.23 to 0.81. In contrast to the Cd-Ca-alginate system, the Mg-Ca-alginate and Mg-Cd-alginate systems yielded maximum values of K*(Mg)Ca (18.0 +/- 1.4) and K*(Mg)Cd (16.0 +/- 0.9) for the alginates extracted from Sargassum fluitans (F(GG) = 0.81; Cuba) and Sargassum thunbergii (F(GG) = 0.75; Korea), respectively. Selectivity studies with mixed-metal pair alginate systems highlight the importance of the specific macromolecular conformation of the alginate polymer in determining metal binding behavior in multiple-metal systems. Furthermore, they demonstrate the importance of the conformation of the alginate as it occurs within the tissue of Sargassum in determining the metal binding behavior of this algal biosorbent. The unique composition of the alginates present in species of Sargassum may represent a distinct advantage over other brown algal species when considering their implementation for the strategic removal of toxic heavy metals from contaminated and industrial wastewaters.

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“…On the other hand, if a large amount of salt is added, precipitation occurs. 13 The properties of alginate and pectin solutions are, in general, affected by physical and chemical parameters, such as temperature, polymer chain size, concentration, water miscible solvents, pH, monovalent salts, polyvalent cations and quaternary ammonium compounds. 14,15 The viscosity of polysaccharides (polyelectrolytes) in "salt-free" solutions is known to present an abnormal behavior, that is, there is a maximum in the reduced viscosity at a certain concentration.…”

Section: Introductionmentioning

confidence: 99%

Dynamic light scattering and viscosimetry of aqueous solutions of pectin, sodium alginate and their mixtures: effects of added salt, concentration, counterions, temperature and chelating agent

Lima¹,

Soldi²

2009

J. Braz. Chem. Soc.

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Efeitos de adição de sal, concentração, presença de contraíons, temperatura e agente quelante em soluções aquosas de pectina, alginato de sódio e misturas destes foram analisadas por viscosimetria e espalhamento de luz dinâmico (DLS). A viscosidade intrínseca dos sistemas binários diminuiu com a adição de sal e com o aumento da temperatura, porém, mostrou-se insensível à adição de NaEDTA. Como esperado, a viscosidade intrínseca do sistema ternário alginato/pectina/água foi igual a média da viscosidade intrínseca determinada para os sistemas binários. Estudos de DLS indicaram a ocorrência de uma distribuição bimodal (presença dos modos de relaxação rápido e lento) para ambos os sistemas binários e ternários a 25 °C, refletindo um processo de agregação. No caso do modo lento de relaxação, um aumento significativo do raio hidrodinâmico foi observado tanto para os sistemas binários como ternário, na presença de NaCl e KCl a 25 °C. No entanto, a 80 °C, o raio hidrodinâmico correspondente ao modo lento em soluções de KCl foi praticamente constante para todos os sistemas estudados e não foi observado para o sistema binário alginato/solução aquosa.The effects of added salt, concentration, counterions, temperature and chelating agent on aqueous solutions of pectin, sodium alginate and their mixtures were analyzed by viscosimetry and dynamic light scattering (DLS) techniques. The intrinsic viscosity of the binary systems decreased with the addition of salt and with temperature, while it was found to be insensitive to the addition of NaEDTA. As expected the intrinsic viscosity of the ternary alginate/pectin/water system was equal to the average of the intrinsic viscosity for the binary systems. The DLS studies indicated a bimodal distribution (fast and slow relaxation modes) for both binary and ternary systems at 25 °C, reflecting aggregation. A significant increase in the hydrodynamic radius, in the case of the slow mode, was observed for the binary and ternary systems in the presence of NaCl and KCl at 25 °C. However, at 80 °C the hydrodynamic radius for the slow mode in KCl solutions was practically constant for all the studied systems, except for the alginate binary solutions in which were not observed.

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Ion Exchange Properties of Alginate Fractions.

Cited by 41 publications

References 0 publications

Uptake of metals by bacterial polysaccharides

Uptake of metals by bacterial polysaccharides

Metal Selectivity of Sargassum spp. and Their Alginates in Relation to Their α-l-Guluronic Acid Content and Conformation

Dynamic light scattering and viscosimetry of aqueous solutions of pectin, sodium alginate and their mixtures: effects of added salt, concentration, counterions, temperature and chelating agent

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