Distribuição de metais e caracterização das constantes de troca entre espécies metálicas e frações húmicas aquáticas de diferentes tamanhos moleculares

Araújo, Adriana Barbosa; Rosa, André Henrique; Rocha, Júlio César; Romão, Luciane Pimenta Cruz

doi:10.1590/s0100-40422002000700011

Cited by 11 publications

(7 citation statements)

References 19 publications

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“…The following increasing order of humification was obtained: F6 < F4,F3 < F1 < F2 < F5. These results are corroborated by those obtained by Araújo et al, 12 who also estimated the extent of humification using A 254 /A 436 ratios. According to Frimmel et al, 13 absorbance (A) in the UV and visible ranges is an important property of NOM.…”

Section: Resultssupporting

confidence: 88%

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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Section: Resultssupporting

confidence: 88%

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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“…The band at 2973 cm −1 was attributed to OH stretching in alcohols and/or phenolic and/or carboxylic acids, and the band at 2925 cm −1 was attributed to the presence of CH stretching in methyl groups and aliphatic methylenes. In addition, the band at 1696 cm −1 was attributed to carbonyl group vibrations in carboxylates and/or ketones (Havers et al, 1998;Araújo et al, 2002;Rocha and Rosa, 2003;Giovanela et al, 2010;Rodríguez and Núñez, 2011), and the band at 1552 cm −1 was attributed to the presence of type II amines (NH). Bands in the region of 1460-1370 cm −1 can be assigned to the presence of CH bonds, CH 3 and the connecting deformations of CH 2 and CH 3 .…”

Section: Resultsmentioning

confidence: 99%

Characterization of typical aquatic humic substances in areas of sugarcane cultivation in Brazil using tetramethylammonium hydroxide thermochemolysis

Tadini

Constantino

Nuzzo

et al. 2015

Science of The Total Environment

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“…Some authors indicate that with pH between 4 and 9, aluminum competes with other metal ions present in the formation of bonds with humic matter, establishing that this element has a higher complexing capability and forms more stable bonds with HS than manganese [28,29]. When the PAC is added in the Table 3 Values of the evaluated parameters in raw water, water after sedimentation, and water after sedimentation plus UF/NF for surface water and groundwater Parameter coagulation step, aluminum can form complexes with the HS, displacing part of the complexed manganese, which is then found as free ion, which is not removed in the step of coagulation or in the UF and NF subsequently.…”

Section: Removal Efficiency For Surface Water and Groundwatermentioning

confidence: 99%

Aquatic humic substances, iron, and manganese removal by ultrafiltration and nanofiltration membranes combined with coagulation–flocculation–sedimentation

Leal

Amaral

Hassemer

et al. 2015

Desalination and Water Treatment

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A B S T R A C TIron and manganese removal is made conventionally by oxidation methods; however, when aquatic humic substances (HS) are present, they can affect the removal, with another treatment process being necessary. This study focused on performance of ultrafiltration (UF) and nanofiltration (NF), preceded by coagulation, flocculation, and sedimentation stages for iron, manganese, and HS removal, with two water sources that present superior levels of humic compounds, and measured by dissolved organic carbon (DOC) and UV absorbance at 254 nm. Coagulation, flocculation, and sedimentation combined with UF/NF efficiently removed dissolved iron, HS, apparent color, and turbidity. Almost total iron removal was already attained in the prior steps of coagulation, flocculation, and sedimentation, obtaining final values of dissolved iron of less than 0.001 mg L −1 for the two types of water studied. However, the complete system did not appear effective (less than 50% efficiency) in dissolved manganese removal, although a significant reduction in the HS was achieved (approximately 80% after UF and 90% after NF measured as DOC, for two types of water). Pretreatment was shown to be effective in reducing the loss of filtration flow because of the removal of high-molecular-weight HS, thus minimizing the formation of fouling on the membrane.

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Distribuição de metais e caracterização das constantes de troca entre espécies metálicas e frações húmicas aquáticas de diferentes tamanhos moleculares

Cited by 11 publications

References 19 publications

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

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

Characterization of typical aquatic humic substances in areas of sugarcane cultivation in Brazil using tetramethylammonium hydroxide thermochemolysis

Aquatic humic substances, iron, and manganese removal by ultrafiltration and nanofiltration membranes combined with coagulation–flocculation–sedimentation

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