Selective extraction of trace metals associated with hydrous aluminum oxides

1987 ◽  
Vol 65 (5) ◽  
pp. 984-989 ◽  
Author(s):  
Janece Slavek ◽  
William Frederick Pickering
Keyword(s):  
Metal Ions ◽  
Selective Extraction ◽  
Metal Species ◽  
Initial Surface ◽  
Aluminum Oxides ◽  
Hydrous Oxides ◽  
Soil Sediment ◽  
Trace Metal Content ◽  
Chemical Solutions ◽  
The Relationship

In soil/sediment analysis, subdivision of trace metal content into different categories is usually based on selective extraction schemes. To assess the disposition of metal ions bound to aluminum hydrous oxides in such schemes, suspensions of Al(OH)3gel, gibbsite, or alumina were loaded with up to 5 μ mol of Cu, Pb, Cd, or Zn ions prior to being extracted for 24 h with one of fifteen different chemical solutions. The percentage of sorbed ion retrieved varied along the reagent sequence: NaCl, CaCl2 < MgCl2, NH4NO3 < CH3COONH4, Na citrate, Na4P2O7 < EDTA, DTPA < CH3COOH, H2C2O4, HCl, HNO3. In each system, the recovery value varied with the initial surface loading (a function of sorption pH) and reflected changes in metal species form, e.g., bonded M2+, (MOH+), M(OH)2. With low loading levels up to 40% was displaced by salt solutions; with 1 to 2 μ mol sorbed, as little as 10% was displaced by acids or complex formers but this increased to ~90% with higher loadings. The relationship between sorption pH, amount sorbed, and extraction value was complex, and since in selective extraction schemes classification is based on recovery values, changes in initial retention parameters (e.g. system pH) lead to varying fractions of the different metal ions being classified as "ion exchangeable", "chemisorbed", and "incorporated in the lattice".

Removal of Heavy Metal Ions from Aqueous Solution by Manganese Dioxide-Coated Polypropylene Granules: An Implication of Rainwater Runoff Treatment

2007 ◽  
Vol 544-545 ◽  
pp. 131-134
Author(s):  
Sardor Abdukakharovich Mavlyankariev ◽  
Dong Seok Rhee
Keyword(s):  
Metal Ions ◽  
Manganese Dioxide ◽  
Surface Area ◽  
Mercury Porosimetry ◽  
Surface Characteristics ◽  
Metal Species ◽  
Adsorption Model ◽  
Rainwater Runoff ◽  
Flow Through ◽  
Fast Removal

Modified polypropylene granules (MDPG) were coated by manganese dioxide and their surface and adsorptive characteristics were studied. Surface characteristics of the adsorbent were investigated by B.E.T. surface area and mercury porosimetry. Coating has significantly increased the surface area of granules from 0.12 m 2 /g B.E.T. N 2 to 15.42 m 2 /g. Gas pycnometry measurements resulted in low density of 0.13 g/cm 3 for uncoated granules, the fact ascribed to 0.65 porosity measured. Coating increased micro pore volume of raw granules by a factor of 58. Adsorption experiments were conducted in column flow-through reactors at pH 6.0 and 10 g/L sorbent dosage for mixture of four metal species, each having 5 mg/L initial concentration. More than 60 % of Pb and Cu was removed within first 20 min, whereas just over 29 and 13 % for Cd and Zn respectively. Furthermore, more than 99, 84, 40, 16 % of Pb, Cu, Cd, and Zn was removed within 1 h. Adsorption efficiencies for 5 ppm of initial metal concentration at pH 5.0 and 10 g/L sorbent/solute ratio resulted in 4.9, 3.9 mg of Pb and Cu sorbed per gram of sorbent. And these ratios for separate metal ions were substantially higher than those for the mixture of the four metal ions. For 5 g/L of sorbent under the same parameters, removal efficiencies of Cd and Zn were respectively 0.98, 0.75 mg/g, correlating well with Freundlich adsorption model. Adsorption kinetics showed relatively fast removal rates within first 5 h of sorption. Desorption resulted in eluting 57, 70, 76, 78 % of the initial feeding concentrations for Pb, Cu, Cd, Zn, respectively.

Selective extraction of metal ions associated with humic acids

Talanta ◽  
1982 ◽  
Vol 29 (9) ◽  
pp. 743-749 ◽  
Author(s):  
J. Slavek ◽  
J. Wold ◽  
W.F. Pickering
Keyword(s):  
Metal Ions ◽  
Humic Acids ◽  
Selective Extraction

scholarly journals Characterization and comparison of PM<sub>2.5</sub> oxidative potential assessed by two acellular assays

2020 ◽  
Vol 20 (9) ◽  
pp. 5197-5210 ◽  
Author(s):  
Dong Gao ◽  
Krystal J. Godri Pollitt ◽  
James A. Mulholland ◽  
Armistead G. Russell ◽  
Rodney J. Weber
Keyword(s):  
Metal Ions ◽  
Water Soluble ◽  
Metal Species ◽  
Urban Site ◽  
Chemical Components ◽  
Linear Regression Models ◽  
Oxidative Potential ◽  
Metal Interactions ◽  
Metal Metal

Abstract. The capability of ambient particles to generate in vivo reactive oxygen species (ROS), called oxidative potential (OP), is a potential metric for evaluating the health effects of particulate matter (PM) and is supported by several recent epidemiological investigations. Studies using various types of OP assays differ in their sensitivities to varying PM chemical components. In this study, we systematically compared two health-relevant acellular OP assays that track the depletion of antioxidants or reductant surrogates: (i) the synthetic respiratory-tract lining fluid (RTLF) assay that tracks the depletion of ascorbic acid (AA) and glutathione (GSH) and (ii) the dithiothreitol (DTT) assay that tracks the depletion of DTT. Yearlong daily samples were collected at an urban site in Atlanta, GA (Jefferson Street), during 2017, and both DTT and RTLF assays were performed to measure the OP of water-soluble PM2.5 components. PM2.5 mass and major chemical components, including metals, ions, and organic and elemental carbon were also analyzed. Correlation analysis found that OP as measured by the DTT and AA depletion (OPDTT and OPAA, respectively) were correlated with both organics and some water-soluble metal species, whereas that from the GSH depletion (OPGSH) was exclusively sensitive to water-soluble Cu. These OP assays were moderately correlated with each other due to the common contribution from metal ions. OPDTT and OPAA were moderately correlated with PM2.5 mass with Pearson's r=0.55 and 0.56, respectively, whereas OPGSH exhibited a lower correlation (r=0.24). There was little seasonal variation in the OP levels for all assays due to the weak seasonality of OP-associated species. Multivariate linear regression models were developed to predict OP measures from the particle composition data. Variability in OPDTT and OPAA were not only attributed to the concentrations of metal ions (mainly Fe and Cu) and organic compounds but also to antagonistic metal–organic and metal–metal interactions. OPGSH was sensitive to the change in water-soluble Cu and brown carbon (BrC), a proxy for ambient humic-like substances.

Changes in aggregate stability and associated organic matter properties after direct drilling and ploughing on some Australian soils

Soil Research ◽  
1980 ◽  
Vol 18 (1) ◽  
pp. 27 ◽  
Author(s):  
AP Hamblin
Keyword(s):  
Metal Ions ◽  
Aggregate Stability ◽  
Selective Extraction ◽  
Continuous Cropping ◽  
Neutral Salt ◽  
Structural Improvement ◽  
Trivalent Metal Ions ◽  
Direct Drilling ◽  
The Stability ◽  
Humic Fractions

After 3-8 years' continuous cropping with conventional cultivation and direct drilling, five Australian soils were examined for changes in structural stability attributable to tillage methods. Some increase in organic carbon was found in four direct drilled soils, and the proportion of carbon in the greater than 2 �m fractions was also higher in these soils after short ultrasonic treatment. Direct drilled soils had significantly greater stability with at least one of the stability tests used, but no soil showed consistently greater stability to five different tests. One direct drilled soil was more stable than its ploughed equivalent after alkaline and neutral salt extraction of metal ions and associated humic substances. One direct drilled soil was more dispersed by polysaccharide extraction. Three direct drilled soils retained greater stability after selective extraction of trivalent metal ions complexed to humic fractions. Structural improvement takes place in Australian soils after several years of direct drilling, but may be at a slower rate and to a lesser extent than has been reported for wetter environments.

scholarly journals Participation of γ-Carboxyglutamic Acid Residues in Metal Binding: 13C nmr Studies of The Interaction of Lanthanide Ions with Bovine Prothrombin Fragment (12-44)

1977 ◽  
Author(s):  
B.C. Furie ◽  
M. Blumenstein ◽  
B. Furie
Keyword(s):  
Metal Ions ◽  
Metal Binding ◽  
Tertiary Structure ◽  
Chemical Shifts ◽  
Lanthanide Ions ◽  
Nmr Studies ◽  
Prothrombin Fragment ◽  
Carboxyglutamic Acid ◽  
The Relationship ◽  
Carboxyl Carbon

Comparative studies of Ca(II) binding to bovine prothrombin and abnormal prothrombin have led to the hypothesis that γ-carboxyglutamic acid (Gla) residues either participate directly in metal liganding or stabilize the tertiary structure of the protein to facilitate metal binding, or both. Extending previous studies of the binding of lanthanide ions to factor X, prothrombin and prothrombin fragment 1, the interaction of lanthanide ions with prothrombin fragment (12-44), which contains eight Gla residues, has been examined by natural abundanceC NMR spectroscopy at 67.88 mHz. The relationship between bound metal ions and carbon atoms in fragment (12-44) was determined using paramagnetic Pr(III) and Eu(III) based upon the strategy that the magnitude of the change in the chemical shift of resonances of the carbon atoms induced by bound metals is related to the interatomic distance between bound metal and carbon nuclei. Assignments of the resonances in the 13C spectrum of fragment (12-44) were based upon our studies of the chemical shifts of carbon resonances in DL-Gla and known chemical shifts of carbon resonances of the other amino acid residues. Titration of fragment (12-44) with Pr(III) or Eu(III) was accompanied by a downfield or upfield shift, respectively, of the γ-carboxyl carbon resonances and no shifts were observed for other carbon resonances. The shift of resonances within the γ-carboxyl carbon envelope appeared selective, suggesting the non-equivalence of the relationship of the γ-carboxyl group of the eight Gla residues to the bound metal ions. These data offer direct evidence that some, but perhaps not all, Gla residues participate in metal liganding.

Sign in / Sign up

Export Citation Format

Share Document