Kinetics of the transformation of phenyl-urea herbicides during ozonation of natural waters: Rate constants and model predictions

Combination of chemical oxidation‐membrane filtration processes for the elimination of phenyl‐ureas in water matrices

“…On the contrary, the ozonation process yielded higher conversion for this herbicide, due to its higher ozonation rate constant than those of the remaining herbicides. The rate constants for the ozonation reaction of these compounds have also been published previously: 13 • C. For these ozonation experiments, the following sequence of degradation was observed: isoproturon > chlortoluron > diuron > linuron, which agrees exactly with the sequence of the mentioned ozonation rate constants. Considering the single ozonation experiments (Expts G-OF-3 and G-OF-4; R-OF-3 and R-OF-4), an increase in the herbicide conversions with increasing initial ozone dose (from 20 to 30 µmol L −1 ) is clearly observed, as could be expected.…”

“…It is also observed that the sequence of conversions (isoproturon > chlortoluron > diuron > linuron) again agreed with the rate constants for the direct reactions between each herbicide and ozone, whose values were previously reported. 13 At the same time, the lower conversion values obtained for the groundwater in comparison with those from the equivalent experiments with the reservoir water are due to the lower ozone dose used (see Table 7): 2 mg L −1 for the groundwater versus 3 mg L −1 for the reservoir water.…”

Boron doped TiO2 catalysts for photocatalytic ozonation of aqueous mixtures of common pesticides: Diuron, o-phenylphenol, MCPA and terbuthylazine

“…The 1 average time needed to reach 99% of pesticides removal with ozone treatments was 2 around 60 min for DIU and TBA, and 30 min for MCPA and OPP. These are, in 3 general, in agreement with the values of the rate constants of the ozone-pesticide [25,30,31]). 5…”

Catalytic ozonation of atrazine and linuron on MnO /Al2O3 and MnO /SBA-15 in a fixed bed reactor

“…= 0.43 ± 0.04 [22][23][24]. This result offers no evidence that any of the catalysts may contribute to an increase in the second order rate constant for the reaction between organics and hydroxyl radicals.…”

“…The compounds tested in this work have a low value of k h O 3 that is 6 M −1 s −1 for atrazine [22], and 1.9 M −1 s −1 for linuron [23]. Batch runs performed in the presence of t-BuOH 10 mM, a well-known radical scavenger, allowed the calculation of the direct catalytic rate constants for degradation of atrazine and linuron, k c O 3…”