10.1021/es202376c.s001
Zhenqing Shi
Zhenqing
Shi
Edward Peltier
Edward
Peltier
Donald L. Sparks
Donald L.
Sparks
Kinetics of Ni Sorption
in Soils: Roles of Soil Organic
Matter and Ni Precipitation
American Chemical Society
2012
Soil Organic Matter
soil Ni speciation
SOM
Ni adsorption
XAS
kinetics model
Ni PrecipitationThe kinetics
2012-02-21 00:00:00
Journal contribution
https://acs.figshare.com/articles/journal_contribution/Kinetics_of_Ni_Sorption_in_Soils_Roles_of_Soil_Organic_Matter_and_Ni_Precipitation/2548042
The kinetics of Ni sorption to two Delaware agricultural
soils
were studied to quantitatively assess the relative importance of Ni
adsorption on soil organic matter (SOM) and the formation of Ni layered
double hydroxide (Ni-LDH) precipitates using both experimental studies
and kinetic modeling. Batch sorption kinetic experiments were conducted
with both soils at pH 6.0, 7.0, and 7.5 from 24 h up to 1 month. Time-resolved
Ni speciation in soils was determined by X-ray absorption spectroscopy
(XAS) during the kinetic experiments. A kinetics model was developed
to describe Ni kinetic reactions under various reaction conditions
and time scales, which integrated Ni adsorption on SOM with Ni-LDH
precipitation in soils. The soil Ni speciation (adsorbed phases and
Ni-LDH) calculated using the kinetics model was consistent with that
obtained through XAS analysis during the sorption processes. Under
our experimental conditions, both modeling and XAS results demonstrated
that Ni adsorption on SOM was dominant in the short term and the formation
of Ni-LDH precipitates accounted for the long-term Ni sequestration
in soils, and, more interestingly, that the adsorbed Ni may slowly
transfer to Ni-LDH phases with longer reaction times.