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A study of the applicability of various activated persulfate processes for the treatment of 2,4-dichlorophenoxyacetic acid
Liang, C.; Guo, Y.-Y. & Pan, Y.-R
Abstract
This paper reports an investigation of different
persulfate (PS) activations, including PS at 20 oC (PS),
thermally activated PS at 70 oC (T-PS), ferrous-ion activated
PS at 20 oC [Fe(II)-PS)], hydrogen peroxide activated
PS at 20 oC, and sodium hydroxide activated PS at 20 oC,
for degradation of the herbicide 2,4-dichlorophenoxyacetic
acid (2,4-D) in aqueous phase. Several findings were made
in this study including the followings: the 2,4-D degradation
rates in T-PS and Fe(II)-PS systems were higher than other
systems. However, complete degradation of 2,4-D and
associated derivatives can be reached in all oxidation systems,
with various reaction times. When considering the
results of PS consumption during the 48 h reaction time to
reach complete 2,4-D degradation, the T-PS system consumed
all of the PS while only 10 % of the PS was consumed
in the Fe(II)-PS system. The evaluation of optimum
PS and ferrous ion doses indicated that under a fixed initial
PS concentration, increasing Fe2+ concentration generally
increased the amount of initial rapid degradation of 2,4-D
and dissolved organic carbon. However, the effectiveness of
the Fe(II)-PS system may be inhibited by the presence of
excess iron. When a fixed level of Fe2+ was employed,
various PS concentrations resulted in approximately equal
2,4-D degradation. The Fe(II)-PS system was found to be
sensitive to the initial Fe2+ concentration, and the presence
of soil revealed minor influence on the 2,4-D degradation by
the Fe(II)-PS system. These findings indicate that the iron-activated
PS process may be an effective method for
remediating 2,4-D contamination.
Keywords
Sodium persulfate; Hydrogen peroxide; Base-activated persulfate; Iron-activated persulfate; Groundwater; Herbicide
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