Reagents
2,4-dichlorophenoxyacetic acid (2,4-D) (Sigma-Aldrich), 2,4 dichlorophenol (2,4-DCP) (Sigma-Aldrich), ferric sulfate (nH2O) (Carlo Erba), hydrogen peroxide (H2O2) (Carlo Erba), acetonitrile (Sigma-Aldrich) and Milli-Q water were used to perform all the experiments . All the reagents were used without further purification.
Natural groundwater samples
Samples were taken from groundwater wells localized in a small rural community (coordinates: 3º21’03.38” N, 76º26’24.51”) near to the municipality of Candelaria (southwest of Colombia). The sample was stored at -4 ºC in plastic bottles and then it was proceed to characterize it (Table 1).
Analysis
Concentrations of 2,4-D and its metabolite 2,4-dichlorophenol (2,4-DCP) were followed …show more content…
Then 10 mg L-1 of H2O2 and 24.3 mg L-1 of 2,4-D were spiked under constant magnetic stirring on the sample and irradiated by a Hanau Suntest (AM-1) solar simulator (Total Intensity: 300 W m-2). The lamp has a spectral distribution with about 0.5% of emitted photons at wavelengths shorter than 300 nm (UV-C range), and about 4% between 300–400 nm (UV-B and UV-A ranges). The distribution of the photons emitted between 400 and 800 nm follows the solar spectrum. The radiant flux was monitored with a Photo-radiometer (HD 2102.2 - Delta Ohm). Temperature of the experiments was never superior to 38 °C. Samples were periodically collected to follow the reaction kinetics.
Evaluation of the effect of hydrogen peroxide, iron concentration and pH on the photo-Fenton process in groundwater samples.
An experimental design 23 with a duplicate was performed to evaluate the effect of H2O2, iron concentration and pH on the photo-Fenton process to degrade 2,4-D in groundwater samples. The levels were 10 and 4 mg L-1 for H2O2, 6.78 and 7.65 to pH and 0.3 and 0.9 mg L-1 for iron concentration. Experiments were performed using the same conditions previously described. Control experiments Fenton at circumneutral pH (dark), photolysis (solar light in absence of iron or H2O2) and photo-Fenton at acid pH were carried out. The results were analyzed using the software Statgraphics Centurion
2,4-dichlorophenoxyacetic acid (2,4-D) (Sigma-Aldrich), 2,4 dichlorophenol (2,4-DCP) (Sigma-Aldrich), ferric sulfate (nH2O) (Carlo Erba), hydrogen peroxide (H2O2) (Carlo Erba), acetonitrile (Sigma-Aldrich) and Milli-Q water were used to perform all the experiments . All the reagents were used without further purification.
Natural groundwater samples
Samples were taken from groundwater wells localized in a small rural community (coordinates: 3º21’03.38” N, 76º26’24.51”) near to the municipality of Candelaria (southwest of Colombia). The sample was stored at -4 ºC in plastic bottles and then it was proceed to characterize it (Table 1).
Analysis
Concentrations of 2,4-D and its metabolite 2,4-dichlorophenol (2,4-DCP) were followed …show more content…
Then 10 mg L-1 of H2O2 and 24.3 mg L-1 of 2,4-D were spiked under constant magnetic stirring on the sample and irradiated by a Hanau Suntest (AM-1) solar simulator (Total Intensity: 300 W m-2). The lamp has a spectral distribution with about 0.5% of emitted photons at wavelengths shorter than 300 nm (UV-C range), and about 4% between 300–400 nm (UV-B and UV-A ranges). The distribution of the photons emitted between 400 and 800 nm follows the solar spectrum. The radiant flux was monitored with a Photo-radiometer (HD 2102.2 - Delta Ohm). Temperature of the experiments was never superior to 38 °C. Samples were periodically collected to follow the reaction kinetics.
Evaluation of the effect of hydrogen peroxide, iron concentration and pH on the photo-Fenton process in groundwater samples.
An experimental design 23 with a duplicate was performed to evaluate the effect of H2O2, iron concentration and pH on the photo-Fenton process to degrade 2,4-D in groundwater samples. The levels were 10 and 4 mg L-1 for H2O2, 6.78 and 7.65 to pH and 0.3 and 0.9 mg L-1 for iron concentration. Experiments were performed using the same conditions previously described. Control experiments Fenton at circumneutral pH (dark), photolysis (solar light in absence of iron or H2O2) and photo-Fenton at acid pH were carried out. The results were analyzed using the software Statgraphics Centurion