흡착여재로 활용되는 금속산화물로 코팅된 모래를 이용한 토양 휴믹산의 흡착 거동

• Published in: 한국수처리학회지, 16(4) pp. 11 - 25
• Main Authors: 김호열, 주진철
• Format: Journal Article
• Language: Korean
• Published: 한국수처리학회 30.12.2008
• Subjects: 토목공학
• ISSN: 1225-7192; 2289-0076

The effects of mineral surfaces and equilibrium pH on the association of bulk, terrestrial humic acid(HA) with three model sorbents [uncoated, FeO(OH)-coated, and Al2O3-coated sands]were investigated using a combination of adsorption kinetics and equilibrium studies. The adsorption and desorption of HA were significantly dependent on the surface compositions of model sorbents and the equilibrium solution pH, and were reasonably well described by the modified Langmuir model. Strong hysteresis effects were observed for both metal (hydr)oxide-coated sands, whereas weaker hysteresis effect was observed for uncoated sand, suggesting that both adsorption and desorption of HA to model sorbents was significantly dependent on the affinity of chemical interactions between the HA and surface compositions of model sorbents. Based on the trends in the values of E4/E6 for the HA during the adsorption kinetics and the sequential adsorption to HA-free mineral surfaces, the adsorption of heterogeneous HA molecules onto both metal (hydr)oxide-coated sands was attributed to a combination of ligand exchange with lower molecular weight fractions and hydrophobic interaction with higher molecular weight fractions. Therefore, both kinetic and fractional adsorption-desorption of HA subcomponents to metal (hydr)oxide-coated sands should be considered to understand the HA adsorption dynamics at solid-water interfaces. The effects of mineral surfaces and equilibrium pH on the association of bulk, terrestrial humic acid(HA) with three model sorbents [uncoated, FeO(OH)-coated, and Al2O3-coated sands]were investigated using a combination of adsorption kinetics and equilibrium studies. The adsorption and desorption of HA were significantly dependent on the surface compositions of model sorbents and the equilibrium solution pH, and were reasonably well described by the modified Langmuir model. Strong hysteresis effects were observed for both metal (hydr)oxide-coated sands, whereas weaker hysteresis effect was observed for uncoated sand, suggesting that both adsorption and desorption of HA to model sorbents was significantly dependent on the affinity of chemical interactions between the HA and surface compositions of model sorbents. Based on the trends in the values of E4/E6 for the HA during the adsorption kinetics and the sequential adsorption to HA-free mineral surfaces, the adsorption of heterogeneous HA molecules onto both metal (hydr)oxide-coated sands was attributed to a combination of ligand exchange with lower molecular weight fractions and hydrophobic interaction with higher molecular weight fractions. Therefore, both kinetic and fractional adsorption-desorption of HA subcomponents to metal (hydr)oxide-coated sands should be considered to understand the HA adsorption dynamics at solid-water interfaces. KCI Citation Count: 1