Adsorption and thermochemical data of divalent cations onto silica gel surface modified with humic acid at solid/liquid interface

Buffer capacity of humic acid: Thermodynamic approach

“…This behavior is caused by a typical chelate effect due to that metal ions are complexed by more than one active binding site of humic acid [21,35]. The chelate effect observed in cation adsorption by humic acid confirms the stabilization of the supramolecular aggregates of humic acid by mordant action with metal ions [4,36].…”

Studies on copper(II)- and zinc(II)-mixed ligand complexes of humic acid

“…The high content of acidic functional groups is responsible for the ability of humic acids (HAs) to interact with inorganic and organic contaminants in soils and natural waters [2]. Furthermore, the interactions of HAs with inorganic and organic contaminants are entropically favoured by virtue of the typical chelate effect [3].…”

Solid Phase Extraction of Thorium and Uranium and their Separation from Lanthanides using Humic Acid Silica Gel as a Low-Cost Adsorbent

“…The silica gel modified by humic acid (Si-HA) used in this study was prepared using a modification of the procedure described by Prado, et al in [8] as follows. Twenty grams of activated silica gel (particle size 40-63 µm) was suspended in 100 mL of dry toluene.…”

“…A silica gel modified with humic acid (Si-HA) has been used to study the binding interaction between humic acid and metal ions, as described by Patel, et al, Prado, et al, Stathi and Deligiannakis in [7][8][9]. However, its applicability for recovering Th and U, including their separation from lanthanides, remains unknown.…”