Field Application of the Stabilization Process for Arsenic-Contaminated Soil - Environmental Contamination: Health Risks and Ecological Restoration - page 461

4

As (1 day)
As (7 day)
As (28 day)
pH (1 day)
pH (7 day)
pH (28 day)

140

120

3

100

80

2

60

40

1

20

0 0

Control 10 15 20 30

(a) PC dose (wt%)

4

140

120

3

100

80

2

60

40

1

20

0

0

Control

20 30

CKD dose (wt%)

40 50

(b)

FIGURE 21.2
As.concentration.and.pH.after.KST.method.for.(a).PC.and.(b).CKD.treatments.after.1,.7,.and.28.
days.of.curing..(From.Yoon,.I.H..et.al.,. J. Environ. Manag .,.91(11),.2322,.2010.)

to.arsenic.contaminated.soil.to.prevent.arsenic.immobilization.via.chem-
ical. ixation. (Moore. et. al.. 2000,. Garcia-Sanchez. et. al.. 2002,. Warren. and.
Alloway.2003).
The. main. mechanism. for. As. stabilization. using. iron. (hydr)oxide. is.
adsorption.. For. example,. Jain. et. al.. (1999). suggested. As(III). and. As(V).
adsorption. onto. ferrihydrite. from. their. study. of. surface. charge. reduc-
tion.and.net.OH − .release.(Jain.et.al..1999)..Table.21.3.indicates.the.adsorp-
tions. of. As(III). and.As(V).at. pH.4.6.and.9.2..The.predominant. species. of.
As(V). at. these. pHs. are. H AsO
2

4 − . and. HAsO 2 − . and. that. of. As(III). at. same.

0 . and. a. mixture. of. H AsO
3

0 . and. H AsO
2 3 − ,. respectively..

pHs. are. H AsO
3 3 3