Conclusions
The kinetics and mechanism of DCF degradation by aqueous
ClO2 were investigated under simulated water treatment conditions.
The following conclusions can be drawn:
(1) DCF may be rapidly and completely oxidized by the presence
of excess ClO2. All of the reactions followed pseudo
first-order with respect to each reactant, and kapp under different
conditions were determined.
(2) The slight variation of kapp under different pH and temperature
exhibited relatively lower dependent on pH and temperature,
with a maximum value of 1.51(±0.017) 103 at
pH 7.0. The activation energy, enthalpy and entropy were
7.87(±0.14) kJ mol1
, 5.38(±0.17) kJ mol1 and
165.75(±3.03) J mol1 K1
, respectively.
(3) The degradation of DCF was significantly inhibited (36.07%)
through the addition of O2
scavengers (chloroform), but not
by HO scavengers (isopropanol), indicating that DCF was
partially oxidized by the O2
that was generated by the reaction
system.
(4) The kinetics model for DCF degradation by ClO2 was established
on the basis of the experimental results obtained.
The proposed mechanism proceeded through two tentative
routes: direct oxidation via ClO2 and indirect oxidation via
O2
.