Resumo (PT):
Abstract (EN):
The treatment of waters/deposits from drinking water networks contaminated with chlorfenvinphos
(CFVP) was performed through the Fenton’s process. Concerning the CFVP degradation in water matrices,
the mineralization and CFVP concentration in a batch reactor were analysed along time for several operating conditions. A detailed parametric study was done to analyse the effect of the initial concentrations
of oxidant (H2O2) and catalyst (Fe2+), temperature and initial pH, allowing concluding that temperature
significantly affects the degradation process. In fact, in the range from 10 to 70 C, the time for complete
degradation of CFVP decreased from 3 h to only 5 min. In the same temperature range, the mineralization
after 3 h increased from 5% to 35%. The effect of other parameters is not so significant; depending on their
values they can affect positively or negatively the responses.
The degradation of the pesticide was assessed for the first time using deposits from water networks as
catalysts. These deposits result from the natural deposition of small particles in suspension, being in
some cases highly rich in iron, and therefore it is envisaged the valorisation of these materials for off-line
applications and the possibility of avoiding the use of some reagents –catalyst – if an in situ treatment is
required.
The decontamination of deposits was assessed in a slurry batch system, showing to be possible to use
iron-rich deposits as catalysts in the oxidation process, as well as to decontaminate them using as catalyst
the iron present in their composition. Results showed that oxidation is fast and effective in the liquid
phase (conversion >95% in 1 h); the pesticide was also removed from the solid, although apparently
not always in a complete manner, in the conditions tested.
Language:
English
Type (Professor's evaluation):
Scientific
No. of pages:
10