Ozonation of Fulvic Acids of Natural Waters in Aqueous Solutions

2003 ◽  
Vol 76 (9) ◽  
pp. 1472-1475 ◽  
Author(s):  
G. V. Slavinskaya ◽  
V. F. Selemenev
Keyword(s):  
Aqueous Solutions ◽  
Natural Waters ◽  
Fulvic Acids

Determination of the aluminium complexing capacity of fulvic acids and natural waters, with examples from five New Zealand rivers

1996 ◽  
Vol 47 (1) ◽  
pp. 11 ◽  
Author(s):  
DJ Hawke ◽  
KJ Powell ◽  
JE Gregor
Keyword(s):  
Reaction Time ◽  
Natural Waters ◽  
Fulvic Acids ◽  
Operational Definition ◽  
Experimental Conditions ◽  
River Waters ◽  
Complexation Capacity ◽  
Complexing Capacity ◽  
Definition Of

An FIA technique with 7 s reaction time was used to analyse free plus labile Al in fulvic acid (FA) solutions and natural waters at pH 4.7, without the need for separation procedures. Titrations of these solutions using incremental pH or total Al were used to determine pH binding curves or estimates of the 'kinetic' Al complexation capacity (Al-CCk) respectively. The operational definition of Al-CCk relates to the capacity of a humic substance or natural water to bind Al through a 7-s FIA reaction time under defined experimental conditions of chromophore (CAS) concentration, ionic strength, and pH. Both Al binding strength and complexation capacity were greater than the corresponding Cu-CC (ISE) values. The Al-CCk measurements at pH 4.7 were 710 μmol Al g-1 v. 590 μmol Cu g-1. Al-CCk results (pH 4.7) were higher for soil FA (710 μmol g-1) than for aquatic FA (390 μmol g-1). Al-CCk results (pH 4.7) for five unfiltered river waters from different catchments gave results in the range 6.5-9.8 μmol Al L-1. The differences between total (natural) Al in the samples and Al-CCk were between 2.7 μM and 8.6 μM. Filtration experiments identified fractionation patterns between total (natural) Al and the fraction of Al-CCk not utilized. The Al titration of alginate, another component of natural organic matter, is reported.

scholarly journals Interactions of hydrophobic metal complexes and their constituents with aquatic humic substances

2007 ◽  
Vol 4 (5) ◽  
pp. 323 ◽  
Author(s):  
Amiel Boullemant ◽  
Jean-Pierre Gagné ◽  
Claude Fortin ◽  
Peter G. C. Campbell
Keyword(s):  
Metal Complexes ◽  
Humic Substances ◽  
Natural Waters ◽  
Hydrophobic Interactions ◽  
Equilibrium Dialysis ◽  
Fulvic Acids ◽  
Suwannee River ◽  
Dissolved Humic Substances ◽  
Ph Range

Environmental context. Lipophilic metal complexes, because they can readily cross biological membranes, are especially bioavailable. However, in natural waters these complexes do not necessarily exist in a free state, i.e. they may bind to the organic matter (humic substances) that is present in natural waters. It follows that the in situ bioavailability of lipophilic metal complexes will tend to be less than that measured in simple laboratory experiments. Abstract. The ability of dissolved humic substances (HS: fulvic and humic acids) to complex cationic metals is well known, but their interactions with neutral lipophilic metal complexes are little understood. In the present study, we have examined the behaviour of two such complexes ( Cd  L 2 0 -->Cd L02: L = DDC = diethyldithiocarbamate, or L = XANT = ethylxanthate) in the presence of Suwannee River Humic and Fulvic acids. Interactions between the neutral complexes and the humic substances were assessed by excitation-emission matrix (EEM) fluorescence spectroscopy at pH 5.5 and 7.0, and by equilibrium dialysis experiments (500 Da cut-off). The EEM measurements were carried out by titrating the humic substances (6.5 mg C L–1) with Cd, in the absence or presence of ligand L (1 µM DDC or 100 µM XANT). Given the very high stability constants for the complexation of cadmium by DDC and XANT and the excess ligand concentration, virtually all (>96%) of the Cd added to the L + HS matrix was calculated to be present as the neutral Cd L 2 0 -->CdL20 complex over the entire pH range tested. For both humic substances, addition of DDC or XANT alone led to shifts in the fluorescence spectra at both pH values, indicating that the DDC– and XANT– anions likely interact by electrostatic or hydrogen bonding within the humic molecules. The subsequent addition of Cd to these L + HS systems resulted in a disproportionately large enhancement of the fluorescence intensities of individual EEM peaks, this fluorescence enhancement being only slightly decreased by the shift from pH 7.0 to 5.5. We interpret this enhancement as evidence that the two neutral complexes associate with the humic substances, presumably by forming ternary complexes (Ln-Cd-HS). Hydrophobic interactions between the humic substances and the neutral complexes may also contribute, but to a lesser extent, as demonstrated by partitioning calculations based on the lipophilicity of the neutral complexes. The association of the neutral complexes with Suwannee River Humic Acid was confirmed by dialysis experiments.

Efficiency of singlet oxygen generation by fulvic acids and its influence on UV photodegradation of herbicide Amitrole in aqueous solutions

2017 ◽  
Vol 27 (4) ◽  
pp. 399-401 ◽  
Author(s):  
Ivan P. Pozdnyakov ◽  
Victoria A. Salomatova ◽  
Marina V. Parkhats ◽  
Boris M. Dzhagarov ◽  
Nikolai M. Bazhin
Keyword(s):  
Aqueous Solutions ◽  
Singlet Oxygen ◽  
Fulvic Acids ◽  
Oxygen Generation ◽  
Singlet Oxygen Generation ◽  
Uv Photodegradation

Rapid quantification of humic and fulvic acids by HPLC in natural waters

2007 ◽  
Vol 22 (8) ◽  
pp. 1598-1605 ◽  
Author(s):  
F.C. Wu ◽  
R.D. Evans ◽  
P.J. Dillon ◽  
Y.R. Cai
Keyword(s):  
Natural Waters ◽  
Fulvic Acids ◽  
Humic And Fulvic Acids ◽  
Rapid Quantification

Nano-Mg/Al hydrotalcite: Physicochemical Characterization and Removal of As(III) from Aqueous solutions

2014 ◽  
Vol 1616 ◽  
Author(s):  
E. Ramos-Ramírez ◽  
N. L. Gutiérrez-Ortega ◽  
G. Rangel-Porras ◽  
G. Herrera-Pérez
Keyword(s):  
Adsorption Isotherm ◽  
Aqueous Solutions ◽  
Natural Waters ◽  
Arsenic Removal ◽  
Sol Gel ◽  
Physicochemical Characterization ◽  
Chemical Characterization ◽  
Kinetic Studies ◽  
Isotherm Models ◽  
Ionic Exchange

ABSTRACTArsenic is one of the most toxic elements that can be found. Arsenic is mainly emitted by the copper, lead and zinc production, in agriculture as pesticides and herbicides. Two forms of arsenic are common in natural waters: arsenite (AsO33−) and arseniate (AsO43−), referred to as As(III) and As(V). The nano-Mg/Al-hydrotalcites present ionic exchange and adsorbent capacities. In this work, the physic-chemical characterization of nano-Mg/Al-hydrotalcites and his arsenic removal capacityis described. The solids were synthesized by the sol-gel method with Mg/Al=2 and 3 ratio. The solids and their thermal treated products were characterized by XRD, FTIR, DTA, TGA and N2 adsorption. The solids were used as adsorbents As(III) in aqueous solutions. Adsorption isotherm studies of As(III) from aqueous solution are described. The adsorbent capacity was determined using the Langmuir, Freundlich and Dubinin–Radushkevich adsorption isotherm models. The As(III) adsorption isotherm data fit best to the isotherm Freundlich model. The maximum As(III) uptake capacity by nano-Mg/Al-hydrotalcites and the heated solids were determined using the Freundlich equation and were found to 547.46, 660.15, 799.88 and 739.12 mg As(III)/g HT-Mg/Al=2, HT-Mg/Al=3, HT-Mg/Al=2 at 350°C and HT-Mg/Al=3 at 350°C respectively. In the kinetic studies using 40 mg/L concentration of As(III) solutions was obtained an excellent removal capacity in contact times less at one minute.

scholarly journals Magnetic iron oxide and manganese-doped iron oxide nanoparticles for the collection of alpha-emitting radionuclides from aqueous solutions

RSC Advances ◽  
2016 ◽  
Vol 6 (107) ◽  
pp. 105239-105251 ◽  
Author(s):  
Matthew J. O'Hara ◽  
Jennifer C. Carter ◽  
Cynthia L. Warner ◽  
Marvin G. Warner ◽  
R. Shane Addleman
Keyword(s):  
Iron Oxide ◽  
Aqueous Solutions ◽  
Iron Oxide Nanoparticles ◽  
Human Urine ◽  
Natural Waters ◽  
Magnetic Nanomaterials ◽  
Oxide Nanoparticles ◽  
Magnetic Iron Oxide ◽  
Ph Range ◽  
Mn Doped

The sorption performance of two amphoteric magnetic nanomaterials, Fe3O4and Mn-doped Fe3O4, has been evaluated for Po, Ra, U, and Am in natural waters (river, ground, and sea) as well as human urine across a pH range.

Stability of hydrolytic arsenic species in aqueous solutions: As3+vs. As5+

2018 ◽  
Vol 20 (36) ◽  
pp. 23272-23280 ◽  
Author(s):  
Giuseppe Cassone ◽  
Donatella Chillé ◽  
Claudia Foti ◽  
Ottavia Giuffré ◽  
Rosina Celeste Ponterio ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Aqueous Solutions ◽  
Ab Initio ◽  
Molecular Dynamics Simulations ◽  
Natural Waters ◽  
Arsenic Species ◽  
Biologically Relevant ◽  
Dynamics Simulations

By combining ab initio molecular dynamics simulations and experiments, the stable hydrolytic species formed by As3+ and As5+ have been identified both in natural waters and in biologically relevant systems.

Metal complexation by organic ligands (L) in near-pristine estuarine waters: evidence for the identity of L

2014 ◽  
Vol 11 (2) ◽  
pp. 89 ◽  
Author(s):  
Hollydawn Murray ◽  
Guillaume Meunier ◽  
Dagmar B. Stengel ◽  
Rachel Cave
Keyword(s):  
Natural Waters ◽  
High Salinity ◽  
Brown Seaweed ◽  
Fulvic Acids ◽  
Organic Ligands ◽  
Metal Interactions ◽  
Low Salinity ◽  
Metal Contents ◽  
Zn Speciation ◽  
Source Structure

Environmental context Metal toxicity to marirne organisms is largely controlled by organic ligands (L) although the source, structure and stimuli of most ligands remain unknown. We studied trends in Cd and Zn complexing ligands in a near-pristine Irish estuary to gain clues on the identity of L in natural waters. The evidence suggests the naturally occurring Cd ligands include fulvic acids whereas the Zn ligands are likely to be exuded from seaweeds. Further research is required to determine their exact identity. Abstract Trace metal interactions with organic ligands largely control metal bioavailability in marine systems, although little is known about the identity of the ligands. To gain insight into the identity of metal complexing ligands (L), surface water and four species of brown seaweed were sampled from four sites in a region of the Lough Furnace Estuary, Ireland with varying salinity. We measured metal (Cd, Cu, Pb, Zn) speciation, complexing ligands, stability constants (log K′), glutathione (GSH), cysteine (Cys) and seaweed metal contents. Although prevalent in seaweed tissue, dissolved Cu and Pb concentrations in water were below the detection limits. Both Cd and Zn occurred in seaweed tissue. In water, both Cd and Zn occurred predominantly complexed to ligands. Levels of complexed Zn increased with decreasing salinity, increasing from 77% at high salinity to 100% at low salinity. Total dissolved Cd showed a mid-salinity decrease in complexation. The concentration of zinc ligands (LZn) ranged from 27.41nM at high salinity to 95.81nM at mid-salinity. Cd ligands (LCd) occurred in the highest concentration, 8.72nM, at mid-salinity. Comparison of the log K′ values with known ligands provided evidence of their identity: similarities were identified for LCd and fulvic acid, and LZn and macroalgal exudates.

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