Membrane filtration studies of aquatic humic substances and their metal species: a concise overview Part 1. Analytical fractionation by means of sequential-stage ultrafiltration

Burba, P.; Aster, Brit; Nifant'eva, T.I.; Shkinev, V. M.; Spivakov, B. Ya.

doi:10.1016/s0039-9140(97)00204-x

Cited by 76 publications

(60 citation statements)

References 36 publications

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“…CFF is a pressure-driven process in which the suspension is re-circulated parallel to the membrane. This restricts the accumulation of particles on the membrane surface, allowing large quantities of water to be processed, while membrane clogging is less of a problem than in standard filtration (Burba et al 1998).…”

Section: Introductionmentioning

confidence: 99%

Size fractionation and characterization of nanocolloidal particles in soils

Zhi-yun

Luo

et al. 2008

Environ Geochem Health

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A protocol was developed to fractionate soil particles down to the nanocolloid scale by combining sieving, sedimentation, centrifugation, and cross-flow filtration (CFF). The validity of the method and the performance of the CFF system were tested by characterizing fractions using laser granulometry, electron microscopy, and chemical analysis. The 0.1-lm-pore-size membrane CFF system effectively retained nanocolloids (\0.1 lm) as shown by laser granulometry and observed directly by transmission electron microscopy. However, environmental scanning electron microscopy images of freeze-dried colloids were very different from their TEM counterparts, suggesting that sample preparation influenced microscopy imaging. Chemical analysis of Cu, Cd, and organic carbon in each fraction showed that the concentrations of these components increased as particle size decreased, indicating colloids and nanocolloids play an important role in retaining trace metals. Particle-size fractionation combined with chemical analysis and electron microscopy can provide insight into the nature and properties of nanocolloids in soil.

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Section: Introductionmentioning

confidence: 99%

Size fractionation and characterization of nanocolloidal particles in soils

Zhi-yun

Luo

et al. 2008

Environ Geochem Health

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“…In addition, the observed chemical structures show no clear repetitive pattern (43)(44)(45). Extremely wide ranges of characteristics are common among complicated mixtures, such as HAs.…”

Section: Fractionation Of Humic Acidmentioning

confidence: 96%

“…Among the fractionation methods available, ultrafiltration (UF) using different suitable membrane filters is a reasonably simple method to differentiate polydisperse mixtures of molecules (44,45). Therefore, molecular size fractionation and classification of HA by UF (56), performed under reproducible and reliable conditions (57), enables such processes to be differentiated as a function of their molecular size.…”

Section: Fractionation Of Humic Acidmentioning

confidence: 99%

Heinrich‐Heine‐Universität Düsseldorf

2017

Geschichte Der Anorganischen Chemie

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“…5 Ultrafiltration systems employing tangential flow (TF) enable relatively rapid filtration, due to reduced pore obstruction since the material accumulated on the membrane surface is removed by the strong cross flow. 6 According to Burba et al,7 UF is one of the few separation methods that do not require either an additional separation medium or additional reagents.…”

Section: Introductionmentioning

confidence: 99%

“…Some studies have suggested that recently-complexed metal ions are preferentially linked with easily accessible functional groups in the organic molecules, with reaction time determining structural changes in NOM molecules and variations in the contents of dissolved organic carbon (DOC) and metals in the various molecular size fractions. [7][8][9][10] Information is therefore needed to improve understanding of the dynamics of natural aquatic systems containing elevated DOC contents, and here we use the example of the Serra de Itabaiana National Park watershed (Brazil). This environmentally protected region contains the headwaters of rivers that are important both from the perspective of water supplies for human consumption, and for irrigation projects affecting around 100,000 inhabitants of an arid region of Sergipe State in northeast Brazil.…”

Section: Introductionmentioning

confidence: 99%

Characterization of interactions between natural organic matter and metals by tangential-flow ultrafiltration and ICP OES

Santos¹,

Romão²,

Oliveira³

et al. 2011

J. Braz. Chem. Soc.

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O fracionamento por tamanho molecular da matéria orgânica natural (MON) de amostras de água do Parque Nacional Serra de Itabaiana (Brasil) foi utilizado para caracterização temporal da complexação de íons metálicos. Um sistema de ultrafiltração em cinco estágios foi usado para separar a MON em seis frações (F1: > 100; F2: 100-50; F3: 50-30; F4: 30-10; F5: 10-5; F6: < 5 kDa). A distribuição obtida, inicialmente para amostra in natura, mostrou que metais (Al, Ba, Cr, Cu, Fe, Mn, Ni, Pb e Sr) foram complexados, preferencialmente, pela fração F1, a qual continha maior concentração de carbono orgânico dissolvido (COD). A seguinte ordem decrescente de distribuição de carbono foi obtida: F1 >> F3 > F2 = F4 > F6 > F5. As frações F2 e F5 foram as mais humificadas e F6 a menos humificada. Após 30 dias com adição de elevadas concentrações de metais nas amostras filtradas novas distribuições de COD e metais foram observadas. Maior COD ainda foi encontrado na F1 com teores de carbono decrescendo na seguinte ordem: F1 > F2 > F3 > F4 > F5 > F6. Os metais apresentaram distribuições similares e homogêneas em todas as frações. Valores de log K foram similares para as amostras in natura e para aquelas de 30 dias após a adição dos metais (7,1 e 7,0; 6,6 e 6,9; e 7,2 e 7,0 para Al, Cu e Fe-MON, respectivamente), indicando uma nova condição de equilíbrio na distribuição dos metais após 30 dias. As espécies formadas entre MON e os metais adicionados mostraram um modelo de distribuição que mudou em função do tempo de complexação, indicando uma transformação dos sítios de ligação da MON, sugerindo que o efeito coletivo das frações é mais importante que as propriedades individuais e confirmando que as frações mais humificadas exercem grande influência na complexação de metais em ambientes aquáticos.Molecular size fractionation of the natural organic matter (NOM) in water samples from the Serra de Itabaiana National Park (Brazil) was used to characterize the temporal behavior of metal ion complexation. A special five-stage tangential-flow ultrafiltration device was used to separate NOM in six size fractions (F1: > 100; F2: 100-50; F3: 50-30; F4: 30-10; F5: 10-5; F6: < 5 kDa). The distribution patterns obtained for one in natura sample showed that metals (Al, Ba, Cr, Cu, Fe, Mn, Ni, Pb and Sr) were preferentially complexed by the F1 fraction, which contained higher concentration of dissolved organic carbon (DOC). The following decreasing order of carbon distribution in the different fractions was obtained: F1 >> F3 > F2 = F4 > F6 > F5. Fractions F2 and F5 were the most humified, and F6 the least. New distributions of DOC and metals were observed after 30 days when high concentrations of metals were added to filtered samples. Highest DOC was still found in F1, with carbon contents decreasing in the following order: F1 > F2 > F3 > F4 > F5 > F6. The studied metals presented similar and homogeneous distributions in all fractions. Values of log K were similar for samples in natura and 30 days after addition of metals (7.1 and 7.0, 6.6 and 6.9, ...

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Membrane filtration studies of aquatic humic substances and their metal species: a concise overview Part 1. Analytical fractionation by means of sequential-stage ultrafiltration

Cited by 76 publications

References 36 publications

Size fractionation and characterization of nanocolloidal particles in soils

Size fractionation and characterization of nanocolloidal particles in soils

Heinrich‐Heine‐Universität Düsseldorf

Characterization of interactions between natural organic matter and metals by tangential-flow ultrafiltration and ICP OES

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