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Mercury Adsorption‐Desorption and Transport in Soils
Author(s) -
Liao Lixia,
Selim H. M.,
DeLaune R. D.
Publication year - 2009
Publication title -
journal of environmental quality
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.888
H-Index - 171
eISSN - 1537-2537
pISSN - 0047-2425
DOI - 10.2134/jeq2008.0343
Subject(s) - mercury (programming language) , adsorption , sorption , soil water , chemistry , environmental chemistry , desorption , freundlich equation , soil science , geology , organic chemistry , computer science , programming language
Kinetic sorption and column miscible displacement transport experiments were performed to quantify the extent of retention/release and the mobility of mercury in different soils. Results indicated that adsorption of mercury was rapid and highly nonlinear with sorption capacities having the following sequence: Sharkey clay > Olivier loam > Windsor sand. Mercury adsorption by all soils was strongly irreversible where the amounts released or desorbed were often less than 1% of that applied. Moreover, the removal of soil organic matter resulted in a decrease of mercury adsorption in all soils. Adsorption was described with limited success using a nonlinear (Freundlich) model. Results from the transport experiments indicated that the mobility of mercury was highly retarded, with extremely low concentrations of mercury in column effluents. Furthermore, mercury breakthrough curves exhibited erratic patterns with ill‐distinguished peaks. Therefore, mercury is best regarded as strongly retained and highly “immobile” in the soils investigated. This is most likely due to highly stable complex formation (irreversible forms) and strong binding to high‐affinity sites. In a column packed with reference sand material, a symmetric breakthrough curve was obtained where the recovery of mercury in the leachate was only 17.3% of that applied. Mercury retention by the reference sand was likely due to adsorption by quartz and metal‐oxides.