Molecular-size-distribution-dependent aggregation of humic substances by Na(I), Ag(I), Ca(II), and Eu(III)

Abstract

Highlights >Molecular-size-distribution (MSD)-dependent aggregation of humics was investigated.>Larger molecular size fractions selectively coagulated by Na and Ca.>The MSD dependence was attributed to non-specific binding of Na and Ca to humics. >Large and small molecular size fractions concurrently coagulated by Ag and Eu.>The reduced MSD dependence was caused by specific binding of Ag and Eu to humics. 3 Graphical Abstract 4 ABSTRACT Molecular-size-distribution (MSD)-dependent aggregation of Fluka and InternationalHumic Substance Society humic acids (HAs) in the presence of Na(I), Ca(II), Ag(I), and Eu(III) were studied using high-performance size-exclusion chromatography. Larger molecular size fractions (>8000 Da) rich in aliphatic carbons were observed to aggregate in the presence of Na(I) and Ca(II), whereas both large and small molecular size fractions concurrently aggregated in the presence of Ag(I) and Eu(III). In view of the non-specific binding of Na(I) and Ca(II) with HAs, the electric-field screening effect is probably the main cause of HA aggregation by Na(I) and Ca (

Humic substances from composted fennel residues control the inflammation induced by Helicobacter pylori infection in AGS cells

“…3, while the relative nominal weight-averaged (Mw) and number-averaged (Mn) molecular weights are reported in Table 3. This humic material showed a bimodal distribution of molecular sizes, as commonly observed for HS of various origins 35,36 . The nominal Mw and Mn for peak A were 83600 Da and 82400 Da, respectively, whereas they were 45200 and 36600 Da for peak B (Table 3).…”

Humic substances from composted fennel residues control the inflammation induced by Helicobacter pylori infection in AGS cells

“…The HPSEC chromatograms of HS from composted fennel wastes are shown in Fig 3, while the relative nominal weight-averaged (Mw) and number-averaged (Mn) molecular weights are reported in Table 3. This humic material showed a bimodal distribution of molecular sizes, as commonly observed for HS of various origins [33,42]. The nominal Mw and Mn for peak A were 83600 Da and 82400 Da, respectively, whereas they were 45200 and 36600 Da for peak B (Table 3).…”

Molecular dynamic simulation of asphaltene co-aggregation with humic acid during oil spill

“…It is speculated that asphaltenes would in turn facilitate the aggregation of humic acids, because there are often metal elements in asphaltenes while humic acids preferred to aggregate in presence of metal ion (Downs and Hall-Wallace, 2003;Tamamura et al, 2013). Therefore, we hypothesized that the asphaltenes in oil and the humic acids in water and sediments would co-aggregate when they interact with each other during oil spill.…”