Binding characteristics of Pb2+ to natural fulvic acid extracted from the sediments in Lake Wuliangsuhai, Inner Mongolia plateau, P. R. China

Zinc Binding to Fulvic acids: Assessing the Impact of pH, Metal Concentrations and Chemical Properties of Fulvic Acids on the Mechanism and Stability of Formed Soluble Complexes

“…This data suggests differences in affinity of the studied fluorophore groups for Zn(II) ions. Chemical heterogeneity of the binding sites in the FA structure was also reported in the studies of Wang et al [10] conducted on Pb(II) interactions as well as in the experiments of Song et al [11] related to the proton binding properties of FAs sub-fractions. Our results demonstrate that A fluorophores, i.e., conjugated aromatic π-electron structures of higher molecular mass, exhibit lower affinity for Zn(II) ions compared to the structures of the B region, i.e., simpler structural components of wide heterogeneity and lower molecular weight.…”

“…FAs compared to other fractions of humic substances (humic acids and humins) reveal a lower molecular weight (~500-2000 Da) [1,2], lower sensitivity to pH and better solubility [3], a structure richer in oxygen compounds [2,4] as well as lower aromaticity [5]. FAs find a wide variety of applications, however the greatest potential of these compounds comes from their chelating properties due to a large number of carboxylic, phenolic and alcoholic hydroxyl functional groups (900-1400 cmol kg −1 ) [6,7] as well as others including quinines, semiquinones [8,9], amino and sulphydryl groups [5,10]. As a consequence, FAs exhibit a high sorption capacity to cationic substances, hence they can play a key role in controlling speciation, bioavailability, toxicity and mobility of metals [11][12][13].…”

“…However, the mechanism of these processes is still poorly understood, and the selection of appropriate conditions for obtaining compounds of the highest stability and microelement content causes multiple problems and requires further comprehensive research. The main difficulty is that both FAs molecules and Zn(II) ions show high sensitivity and variability to changes in pH, ionic strength, free metal ion concentration and the presence of competing ions [10,11]. Zn at low pH and in the absence of organic ligands is present as hydrated Zn 2+ (aq) [29].…”

Effect of microplastics on the binding properties of Pb(ii) onto dissolved organic matter: insights from fluorescence spectra and FTIR combined with two-dimensional correlation spectroscopy

“…[9][10][11] Previous studies have revealed that owing to the presence of functional groups, such as hydroxylic, carboxylic and alcohol hydroxylic groups, DOM can interact with metal ions in several ways, including complexation, ion exchange and reduction, which indicates that DOM is believed to have important effects on heavy metal speciation, transport, and bioavailability. [12][13][14] However, in reality, in environments other than heavy metals and DOM, other inorganic/organic pollutants are also present; inevitable interactions result in more complex environmental behaviors. For example, sediment resuspension in lake water signicantly decreases the heavy metal binding affinity of DOM, which might be attributed to binding competition from inorganic colloids.…”

Measurement of Complex Formation Process of Nickel (II) with Freshwater Fulvic Acids Using the Solubility Method

“…The elemental composition (%) of FA is isolated from natural waters changes C 46.7~59.7; H 4.1~5.5; O 31.8~49.7; N 0.74~3.3 and S 0.4~1.7. 1,[7][8][9][10] FA form stable complexes with heavy metals and radionuclides 1,[11][12][13][14][15][16][17][18][19][20][21] and stipulate migration forms thereof in natural waters and soils. 1,3,[22][23][24][25][26][27] Therefore, FA may affect the transport, accumulation, bioavailability, and toxicity of metals in the environment.…”