Humic like substances for the treatment of scarcely soluble pollutants by mild photo-Fenton process

Caram, Bruno Federico; García-Ballesteros, Sara; Santos‐Juanes, Lucas; Arqués, A.; García-Einschlag, Fernando S.

doi:10.1016/j.chemosphere.2018.01.074

Cited by 18 publications

(20 citation statements)

References 28 publications

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“…Finally, HLS are able to improve the photo-Fenton-based degradation of pollutants at amounts that are above the limit of solubility. 23 This might be attributed to the surface active properties of these substances that are able to confine the pollutants inside the micelles and, at the same time, to approach the substrates and the photo-Fenton system.…”

Section: Introductionmentioning

confidence: 99%

Unveiling the Dependence between Hydroxyl Radical Generation and Performance of Fenton Systems with Complexed Iron

et al. 2019

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Humiclike substances (HLS) have been demonstrated to be useful auxiliaries to drive the (photo)-Fenton process at mild pH, by avoiding iron inactivation via formation of active complexes. However, the actual performance of the process is affected by a manifold of opposite processes. In this work, the generation of hydroxyl radical-like reactive species in the Fentonlike process has been investigated using electron paramagnetic resonance, employing 5,5-dimethyl-1-pyrroline-N-oxide as a probe molecule. The signal obtained with the Fe(II)–HLS–H2O2 system at pH = 5 was very intense but decreased with time, in line with the difficult reduction of the formed Fe(III) to Fe(II). On the contrary, the signal of the Fe(III)–HLS–H2O2 system was weak but stable. The most intense signal was observed at HLS concentration of ca. 30 mg/L. Interestingly, the performance of the Fenton system at pH = 5 to degrade caffeine followed the same trends, although caffeine removal was very low after 1 h of irradiation. The results were more evident in a solar simulated photo-Fenton process, where an increase in the abatement of caffeine was observed until an HLS concentration of 30 mg/L, where 98% removal was reached after 1 h.

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Section: Introductionmentioning

confidence: 99%

Unveiling the Dependence between Hydroxyl Radical Generation and Performance of Fenton Systems with Complexed Iron

et al. 2019

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“…The treatment time required to decrease in an 80% the sum of the concentration of the 6 pollutants that could be analysed via liquid chormatography (t80%), was used as response. This type of parameters have been used in previous papers for statistical analysis as it provides a more "visual" information of the time required to achieve the desired result when compared with with pseudo-first order kinetic constants (Gomis et al, 2015, García-Ballesteros et al, 2017Caram et al, 2018). In particular t80% was chosen in order to ensure that a significant degradation of the pollutants occurred (80%) and to avoid the asymptotic behaviour of the concentration vs time plot observed at values close to 100% degradation and that results in important errors in the determination of the required time of treatment.…”

Section: Statististic Analysismentioning

confidence: 99%

A new methodology to assess the performance of AOPs in complex samples: Application to the degradation of phenolic compounds by O3 and O3/UV-A–Vis

et al. 2019

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A methodology combining experimental design methodology, liquid chromatography, excitation emission matrixes (EEM) and bioassays has been applied to study the performance of O3 and O3/UVA-vis in the treatment of a mixture of eight phenolic pollutants. An experimental design methodology based on Doehlert matrixes was employed to determine the effect of pH (between 3 and 12), ozone dosage (02-1.0 g/h) and initial concentration of the pollutants (1-6 mg/L each). The following conclusions were obtained: a) acidic pH and low O3 dosage resulted in an inefficient process, b) increasing pH and O3 amount produced an enhancement of the reaction, and c) 2 interaction of basic pH and high amounts of ozone decreased the efficiency of the process. The combination of O3/UVA-vis was able to enhance ozonation in those experimental regions were this reagent was less efficient, namely low pH and low ozone dosages. The application of EEM-PARAFAC showed four components, corresponding to the parent pollutants and three different groups of reaction product and its evolution with time. Bioassys indicated important detoxification (from 100% to less than 30% after 1 min of treatment with initial pollutant concentration of 6 mg/L, pH = 9 and ozone dosage of 0.8 g/h) according to the studied methods (D. magna and P. subcapitata). Also estrogenic activity and dioxin-like behavior were significantly decreased.

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“…These substances have been demonstrated to be photo-active and able to catalyze degradation of pollutants, namely phenols, although the process is slow [10]. On the other hand, their ability to complex iron [11], and to drive efficiently photo-Fenton to pH values slightly above 5, has been demonstrated [12,13].…”

Section: Introductionmentioning

confidence: 99%

Photo-Fenton Degradation of Pentachlorophenol: Competition between Additives and Photolysis

et al. 2019

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In the present work, the photo-Fenton degradation of pentachlorophenol (PCP, 1 mg/L) has been studied under simulated and natural solar irradiation; moreover, the effect on the process efficiency of urban waste-derived soluble bio-based substances (SBO), structurally comparable to humic acids, has been investigated. Experiments showed a crucial role of PCP photolysis, present in the solar pilot plant and hindered by the Pyrex® filter present in the solar simulator. Indeed, the SBO screen negatively affects PCP degradation when working under natural solar light, where the photolysis of PCP is relevant. In contrast, in the absence of PCP photolysis, a significant improvement of the photo-Fenton process was observed when added to SBO. Furthermore, SBO were able to extend the application of the photo-Fenton process at circumneutral pH values, due to their ability to complex iron, avoiding its precipitation as oxides or hydroxides. This positive effect has been observed at higher concentration of Fe(II) (4 mg/L), whereas at 1 mg/L, the degradation rates of PCP were comparable in the presence and absence of SBO.

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Humic like substances for the treatment of scarcely soluble pollutants by mild photo-Fenton process

Cited by 18 publications

References 28 publications

Unveiling the Dependence between Hydroxyl Radical Generation and Performance of Fenton Systems with Complexed Iron

Unveiling the Dependence between Hydroxyl Radical Generation and Performance of Fenton Systems with Complexed Iron

A new methodology to assess the performance of AOPs in complex samples: Application to the degradation of phenolic compounds by O3 and O3/UV-A–Vis

Photo-Fenton Degradation of Pentachlorophenol: Competition between Additives and Photolysis

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