TITLE:
Extraction of Lead, Cadmium and Nickel from Contaminated Soil Using Acetic Acid
AUTHORS:
Hatem Asal Gzar, Awatif S. Abdul-Hameed, Asmaa Younus Yahya
KEYWORDS:
Contaminated Soil, Soil Washing, Extraction, Organic Acid, Heavy Metals
JOURNAL NAME:
Open Journal of Soil Science,
Vol.4 No.6,
June
25,
2014
ABSTRACT: The accumulation of
heavy metals in soil is a serious environmental problem. It is well known that
heavy metals have an affinity for different compartments of soil. The risk
associated with the presence of metals in soil is the ability of their transfer
in water or plants. In the present research, batch extraction experiments were
conducted using acetic acid (AA) as an extractant solution at various
concentrations and contact times to determine the best conditions of soil
washing process to achieve high heavy metal removal efficiencies. AA was
investigated for its applicability for the removal of lead, cadmium and nickel
from soil. Batch soil washing experiments were performed on 1.0 g portions of
the spiked soil using different concentrations (0.001, 0.005, 0.01, 0.05, and
0.1 mol/L) of AA (CH3COOH) with solid: liquid ratio of 1:10. The
results showed that AA extracted greater Pb than Cd and Ni. The extraction was
carried out with shaking times from 15 to 180 min. The removal percentage of Pb
varies from 42.2%-100% and Cd from 5.2%-31.1% with increasing concentration
of AA, while the removal efficiency of Ni was not exceeded about 1%. Comparing
with Pb and Cd, the removal efficiency of Ni was very low; this means that the
solubility of Ni in AA was very low. It was found that 0.1 mol/L AA for soil
washing was effective in removing absorbed Pb from contaminated soil (100%
efficiency) at time 15 min. While the efficiency reaching 100% with washing
solution of 0.05 and 0.01 mol/L at times 120 and 180 min, respectively. The
efficiencies of Cd and Ni extraction were
improved when 1 mol/L of AA solution was used (41.3% to 70.6% for Cd and
16.3% to 23.3% for Ni).