Combining ozone with UV and H₂O₂ for the degradation of micropollutants from different origins: lab-scale analysis and optimization

Abstract

The degradation of micropollutants (MPs), including pesticides, herbicides, pharmaceuticals and endocrine disrupting compounds, by ozone-based advanced oxidation techniques (AOP) was investigated in this study. The effect of different factors, such as ozone concentration, hydrogen peroxide concentration and initial pH, on the removal rate was studied in detail. The combination of UV with ozone/ HO increased the MPs degradation. For example, atrazine removal increased from 12.6% to 66.9%. Increasing the concentration of ozone and HO can enhance the degradation efficiency of MPs, while excess HO plays a role as a scavenger for OH. In addition, the optimizing conditions of degradation of MPs by an ozone-based AOP were investigated in this study. The optimal dosages of ozone for atrazine (ATZ), alachlor (ALA), carbamazepine (CBZ), 17-α-ethinylestradiol (EE2) and pentachlorophenol (PCP), were in the range of 0.6-0.75, while for ATZ a much higher dosage (5.4 mg/l) is needed. The optimal dosages of HO concentration were at 0.75, 0.2, 0.47, 0.75 and 0.63 mM, and pH were at 10, 10, 7, 10 and 10, and reaction time at 38.5, 33.5 43, 6 and 6 min, respectively. Ozone-based AOP and in particular combination of UV with ozone and HO is efficient to degrade atrazine, alachlor, carbamazepine, 17-α-ethinylestradiol and pentachlorophenol, and is attractive for future application of real wastewater treatment.

A proof of concept study for wastewater reuse using bioelectrochemical processes combined with complementary post-treatment technologies

“…6 Lee et al (2016) 7 investigated several oxidation processes at a bench-scale level and demonstrated their effectiveness in increasing the removal of persistent organic contaminants from wastewater effluents. A similar conclusion was also drawn by Liu et al (2018). 8 In the context of oxidation byproducts as effectively as removing TOrCs from wastewater.…”

“…A similar conclusion was also drawn by Liu et al (2018). 8 In the context of oxidation byproducts as effectively as removing TOrCs from wastewater. The formation of toxic byproducts is typically less of an issue for UV/H 2 O 2 .…”

Mechanistic Model and Optimization of the Diclofenac Degradation Kinetic for Ozonation Processes Intensification

“…The former allowed oxide-reduction reactions to take place. Thus, the holes promoted the generation of hydroxyl radicals by reactions (20) and (21), while electrons reacted with ozone to produce ozonide radicals (24). However, recombination of the photo-generated pair was also possible.…”

“…These processes have overcome kinetic limitations from traditional AOPs for a broad range of CECs from pharmaceutical, pesticidal, and petrochemical industries [15][16][17]. In addition, ozone-based intensifications are a promising field for wastewater treatments because it exploits the unstable behavior of the ozone molecules by promoting its interaction with UV and different types of catalysts such as zeolites, activated carbon, and semiconductors [18][19][20][21].…”

Degradation mechanism of tributyl phosphate by UV/H2O2 treatment and parameters optimization towards the design of a pilot reactor

“…Phosphate release levels off at 40 molar equivalents of H 2 O 2 , indicating that adding more hydrogen peroxide does not improve the degradation of TBP. At higher concentrations, the supplementary hydroxyl radicals are readily scavenged by the excess of peroxide and do not react with the pollutant [28][29][30][31]. The rate constant of the reaction between H 2 O 2 and • OH is 1.7-4.5 × 10 7 L.mol −1 .s −1 , which is about hundred times less than for the oxidation of TBP by • OH (6.4 × 10 9 L.mol −1 .s −1 [11]), explaining the order of magnitude of excess concentration required for the competition effect to be observed.…”