| Summary: | 碩士 === 國立中央大學 === 環境工程研究所 === 83 === The ability of clays to remove nonionic organic contaminants
(NOCs) from leachate can be greatly enhanced by ion-exchange
reactions of organic cations for natural inorganic exchange
ions. Three different types natural clays incorporated with
modified clays that were natural clays exchanged with organic
cations, were conducted to evaluate the changes in permeability
under organic permeants. Three different modified clays were
tested: Hexadecyltrimethyl ammonium (HDTMA), Dodecyltrimethyl
ammonium (DDTMA), and Tetramethyl ammonium (TMA). Organic
permeants are methanol and acetone diluted with deionized
water. Tests are conducted in specially designed of flexible
wall permeameter that provides precise measurements of
pressures and flows. The results of test show that: (1)The
clays permeability almost does not change under 5%
concentration of methanol and acetone. (2) Under 40% methanol
water-solution, the clay''s permeability reduces to about 60%.
(3) The addition of TMA modified clay can reduce the
permeability of the clays column, but do not effect on its
sorption of lindane. (4) 5% additions of HDTMA or DDTMA
modified clay can slightly reduce the permeability of the clays
column, but 15% additions increase the permeability. (5) By
Adding HDTMA or DDTMA modified clay into the pure clay can
reduce the outflows concentration of lindane. (6) The addition
of HDTMA modified clays can keep the capacity to avoid
transportation of lindane under organic permeants, but the
addition of DDTMA modified clays cannot.
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