Separation of Fulvic Acid from Soil Extracts Based on Ion-Pair Formation with a Cationic Surfactant

Removal of Trace Levels of Cu(II) from Seawater by Co-precipitation with Humic Acids

“…29 Based on this, the absorptivity at 280 nm (ε280) is commonly used as an index of the degree of aromaticity of humic substances. 19,[24][25][26] The higher value of the original ε280 for HHA indicates that it contains a higher degree of aromatic structures than SHA and PHA, consistent with the features of pyrolysates (Fig. 5).…”

Coagulation performance and floc characteristics of aluminum sulfate with cationic polyamidine as coagulant aid for kaolin-humic acid treatment

“…In previous reports, surface tension of HA increased above pH 6, suggesting that HA became to be difficult to aggregate above pH 6 [31]. In addition, ion-pair formation between fulvic acid and alkylammonium surfactants is optimal at pH 7, and the higher pH resulted in the decrease of the formation [32]. These issues suggest that HA becomes to be difficult to coagulate in neutral to weak alkaline condition.…”

Characterization of seawater extractable organic matter from bark compost by TMAH-py-GC/MS

“…The extraction and purification of HA and FA were based on a method approved by the International Humic Substances Society [19,20]. The mixture of dry compost and 0.05 M aqueous NaOH (solid/liquid = 1:10, w/w) was shaken under a N 2 atmosphere for 24 h. Subsequently, the suspension was centrifuged at 10,397 × g for 15 min, and the supernatant was then filtered through an ADVANTEC 5A filter paper (collected particle size >0.7 m; ash content <0.01%).…”