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International Journal of Environment Science and Technology
Center for Environment and Energy Research and Studies (CEERS)
ISSN: 1735-1472 EISSN: 1735-1472
Vol. 12, No. 2, 2015, pp. 617-632
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Bioline Code: st15056
Full paper language: English
Document type: Research Article
Document available free of charge
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International Journal of Environment Science and Technology, Vol. 12, No. 2, 2015, pp. 617-632
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Arsenic removal from soil with high iron content using a natural surfactant and phosphate
Mukhopadhyay, S.; Hashim, M.A.; Allen, M. & Sen Gupta, B.
Abstract
An environment friendly arsenic removal
technique from contaminated soil with high iron content
has been studied. A natural surfactant extracted from
soapnut fruit, phosphate solution and their mixture was
used separately as extractants. The mixture was most
effective in desorbing arsenic, attaining above 70 % efficiency
in the pH range of 4–5. Desorption kinetics followed
Elovich model. Micellar solubilization by soapnut
and arsenic exchange mechanism by phosphate are the
probable mechanisms behind arsenic desorption. Sequential
extraction reveals that the mixed soapnut–phosphate
system is effective in desorbing arsenic associated with
amphoteric–Fe-oxide forms. No chemical change to the
wash solutions was observed by Fourier transform-infrared
spectra. Soil:solution ratio, surfactant and phosphate concentrations
were found to affect the arsenic desorption
process. Addition of phosphate boosted the performance of
soapnut solution considerably. Response surface methodology
approach predicted up to 80 % desorption of arsenic
from soil when treated with a mixture of ≈1.5 % soapnut,
≈100 mM phosphate at a soil:solution ratio of 1:30.
Keywords
Soil washing; Soapnut; Phosphate; Sapindus mukorossi; Arsenic
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