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Removal of
arsenic from contaminated water by foam flotation Foam
flotation has been employed in this work for enhanced removal of arsenic species from
water. The method involves interactions between arsenic species or arsenic-hydrolysable
multi-cation complexes and surfactants, and removal of the hydrophobic complexes formed by
air bubbles under quiescent conditions. The system in our experiments consisted of
arsenic(V) oxide hydrate, aluminum chloride, sodium dodecyl sulfate (CH3(CH2)11OSO3Na),
dodecylamine (CH3(CH2)11NH2), and frothers. It was found that as much as 99% removal of
arsenic species can be obtained by adsorbing colloid flotation, the removal being depended
upon the solution pH, the ratio of arsenic to aluminum chloride and the interactions
between the arsenic-multication species and the surfactants used as collectors. The low
removal (less than 10%) of arsenic species by ion flotation in our experiments suggests
that the interactions between arsenic species and oppositely charged surfactants may be
weak, and therefore an activator is needed to transform arsenic species into more ionic
forms for the ionic flotation of arsenic species. These results show that flotation based
on the interactions between arsenic-multication species and surfactants is a new effective
method either by itself or in combination with other techniques for the removal of arsenic
from effluents. |
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