Effect of dissolved organic matter on adsorption and desorptionof mercury by soils
YANG Yongkui , LIANG Li , WANG Dingyong
DOI:
Received October 22, 2007,Revised January 31, 2008, Accepted , Available online
Volume 20,2008,Pages 1907-1102
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Effects of dissolved organic matter (DOM) on adsorption and desorption of Hg were investigated in two kinds of soils, Xanthi-Udic
Ferralosols (XUF) and Typic Purpli-Udic Cambosols (TPUC). The DOM was obtained from humus soil (DOMH), rice straw (DOMR),
and pig manure (DOMP). The presence of DOM obviously reduced Hg maximum adsorption capacity with up to 40% decreases over
the control, being an order of DOMH (250.00 mg/kg)< DOMR (303.03 mg/kg) < DOMP (322.58 mg/kg) < CK (control 416.67 mg/kg)
for the XUF and DOMH (270.27 mg/kg) < DOMR (312.50 mg/kg) < DOMP (324.23 mg/kg) < CK (476.11 mg/kg) for the TPUC,
respectively. The inhibition of DOM on Hg adsorption was slightly weaker in XUF than in TPUC. Meanwhile, the DOM promoted
Hg desorption from the soils. The kinetic models, the Two-constant equation and Elovich equation, were applicable to describe the
adsorption and desorption processes of Hg in soils. The speed of Hg adsorption was consistently slowed down by the existence of
DOM.
