Impact factors and thermodynamic characteristics of aquatic humic acid loaded onto kaolin.
The adsorption of humic acid (HA) on kaolin particles was studied at various conditions of initial solution pH, ionic strength and solid-to-liquid ratio. The resulting affinity of interactions between humic acid and kaolin was attributed to the surface coordination of HA in ambient suspensions of mineral particles and the strong electrostatic force at low pH. Addition of inorganic salt can also influence the adsorption behavior by affecting the HA molecular structure, the clay particle zeta potential and so on. Equilibrium data were well fitted by the Freundlich model and implied the occurrence of multilayer adsorption in the process. In addition, the enthalpy dependent of system temperature was 79.17 kJ/mol, which proved that the mechanism of HA adsorption onto kaolin was comprehensive, including electrostatic attraction, ligand complexation and hydrogen bonding.
Shandong Key Laboratory of Water Pollution Control and Resource Reuse, School of Environmental Science and Engineering, Shandong University, No. 27 of Shanda South Road, Jinan 250100, PR China. qyyue@sdu.edu.cn
Yue
Y
Qinyan
Li
L
Ying
Gao
G
Baoyu
D000327:Adsorption; D006812:Humic Substances; D006863:Hydrogen-Ion Concentration; D007616:Kaolin / Q000737:chemistry*; D009994:Osmolar Concentration; D013816:Thermodynamics
D006812:Humic Substances; D007616:Kaolin