Advanced oxidation processes

[CEST2019_00900] Elimination of relevant pharmaceuticals in hospital wastewater from Colombia by combination of a biological system with a sonochemical process
by Torres-Palma R., Serna-Galvis E., Hernández F., Botero-Coy A.M., Moncayo-Lasso A., Silva-Agredo J.

In this work conventional biological treatment was applied to raw HWW. After 36h, such process mainly removed biodegradable substances, but had a limited action on the pharmaceuticals. The resultant biotreated water was submitted to the sonochemical process (375 kHz and 88 W L-1, 1.5 h), which due to its chemical (i.e., radical attacks) and physical (i.e., suspended solids disaggregation) effects induced a considerable pharmaceuticals degradation (pondered removal: 58.82%), demonstrating the complementarity of the proposed combination. Afterwards, Fe2+ (5 ppm) and UVC light (4W) were added to the sonochemical system (generating sono-photo-Fenton process), which significantly increased up to 82.86% the pondered pharmaceuticals removal. Finally, it was found that 91.13% of the initial pharmaceuticals load in HWW was removed by the biological/sono-photo-Fenton combination.

Session: 17, Room: E, at Thu, 09/05/2019 - 15:45 to 16:00
Oral presentation in Advanced oxidation processes
[CEST2019_00766] Micro-pollutants, Oxidants, Catalysts and the Water Matrix: A Harmonic Quartet or the War of the Roses?
by Mantzavinos D.

Advanced oxidation processes (AOPs, e.g. heterogeneous and homogeneous photocatalysis, electrochemical oxidation, ozonation, ultrasound irradiation, Fenton and alike reactions, and many more) have been investigated for the treatment of emerging pollutants over the past 20 years (Klavarioti et al., 2009). In particular, the occurrence of persistence micro-pollutants in various water matrices, such as pharmaceuticals and personal care products, raises serious environmental concerns since these xenobiotics can re-enter the water cycle, i.e. escaping intact from the conventional wastewater treatment plants and finally ending up in surface and ground waters (Verlicchi et al., 2012).AOPs can effectively degrade organic pollutants typically found in environmental matrices (secondary treated effluents, surface waters, ground waters) at concentrations ranging from the ng/L to low mg/L level. This said, the specific treatment cost (i.e. the cost per unit mass of removed pollutant and/or per unit volume of effluent), as well as the environmental footprint are generally high; both are usually related to the treatment performance, which, in turn, depends on the specific treatment conditions and the quality of the water matrix.

Session: 5, Room: E, at Thu, 09/05/2019 - 09:00 to 09:30
Oral presentation in Advanced oxidation processes
[CEST2019_00665] Bacterial inactivation & study of damages in subcellular level during disinfection of aqueous samples
by Gounaki I., Lironi M.A., Venieri D.

The aims of the study were i) to investigate ozonation and UVA/TiO2 photocatalysis as water disinfection techniches & ii) to study damages in subcellular level, in terms of disinfection effects on cellular components (lipids, membrane and proteins). Disinfection experiments were conducted with the bacterial strains Escherichia coli, Pseudomonas aeruginosa and Bacillus cereus. Ozonation proved to be more effective for the disinfection of aqueous samples compared with UV-A photocatalysis, as for the Gram (-) bacteria a complete reduction was achieved within 15 min, whereas for the Gram (+) bacteria the same reduction was obtained within 30 min.
Regarding the subcellular level the lipid peroxidation progressed at an exponential rate in the course of treatment. The ONPG hydrolysis assay showed negligible alterations in teh course of treatment, indicating that the cell membrane may act as an effective barrier between the cytoplasm and the outer solution in each case.

Session: 17, Room: E, at Thu, 09/05/2019 - 16:09 to 16:12
Flash presentation in Advanced oxidation processes
[CEST2019_00637] A practical time discretization methodology for adjusting the dosage profile in photo-Fenton processes
by Xiangwei Y., Graells M., Pérez-Moya M.

This work is aimed at systematically determining conditions enhancing the performance of Photo-Fenton processes and improving the mineralization of aqueous solutions containing emergent pollutants. Current investigations cannot provide definitive solution approaches yet and optimizing H2O2 dosage is still a challenge. Thus, this work adopts recipe optimization concepts based on time discretization for experimentally addressing the optimization of the dosage profile. Results show the practicability of the solution, and discussion provides insight for the generalization of an optimization procedure.

Session: 17, Room: E, at Thu, 09/05/2019 - 16:03 to 16:06
Flash presentation in Advanced oxidation processes
[CEST2019_00639] 3D printed lab-scale raceway ponds reactors applied to photo-Fenton processes
by Nasr Esfahani K., Zandi M.D., Travieso-Rodriguez J.A., Graells M., Pérez-Moya M.

In this work, two different printable materials, PLA (polylactic acid) and Timberfill were evaluated in terms of chemical resistance to photo-Fenton reactants and viability for conducting the assays in raceway pond reactors (RPRs). The modeling and testing of chemical reactors, in particular their prototyping can benefit from additive manufacturing. However, the preparation of RPRs by 3D printing to study photo-Fenton reactions has not been investigated. First, these raw materials were exposed to H2O2/Fe(II) solutions at pH=3±0.2 under sunlight to simulate photo-Fenton environment. TOC analysis showed that PLA did not alter the concentration of TOC of the solution in the presence of H2O2 and iron. Furthermore, printed PLA and Timberfill lab-scale raceway ponds were examined under similar conditions in addition 30±0.5 mg·L-1 of caffeine as contaminant and involving the simultaneous exposition of the artificial UVA light. Through different assays in the PLA pond, TOC was not rised during operation, and no organic matter contaminated the solution from its container. However, in the case of Timberfill, the TOC of solution increased that represented the material destruction during contact time. This work shows the promising capability of PLA to be used as photo-Fenton reactor.

Session: 17, Room: E, at Thu, 09/05/2019 - 16:06 to 16:09
Flash presentation in Advanced oxidation processes
[CEST2019_00652] New evidence of accelerated elimination of an emergent water pollutant by TiO2 assisted photo-oxidation
by Favier L., Laslau A., Simion A.I., Sescu A.M., Harja M., Rusu L.

This study focuses on the photocatalytic degradation of a pharmaceutic compound essentially employed for the treatment of hypertension using TiO2 as catalyst and UV-A irradiation. An efficient elimination yield of 99% was obtained after 10 minutes of irradiation at initial pollutant concentration of 5 mg/L and 1.2 g/L of catalyst. A higher mineralization yield of 87% was reached in 2h of reaction. Results showed that under all studied process conditions the target molecule was degraded according to a pseudo first order kinetics. Obtained data clearly demonstrate the potential application of the investigated process for the remediation of polluted water.

Session: 17, Room: E, at Thu, 09/05/2019 - 15:30 to 15:45
Oral presentation in Advanced oxidation processes
[CEST2019_00596] Laboratory scale study of photolytic and photooxidative treatment for removal of pharmaceutical residues from water matrices
by Záray Gy., Dóbé S., Gombos E., Krakkó D., Mihucz V.G.

Photolytic and photooxidative degradations of diclofenac (DICL), naproxen (NAPR) and carbamazepine (CARB) were studied applying a batch photo-reactor containing low-pressure mercury lamp emitting at 185 and 254 nm. The drugs were added in concentration of 5×10-6 M to ultra-pure water (UPW) and biologically treated wastewater (BTWW). Almost complete photolytic and photooxidative degradations were observed by VUV irradiation for DICL, NAPR and CARB in UPW within 1.0, 1,0 and 1.5 min, respectively. But in the spiked BTWW matrix, the efficient degradation of DICL, NAPR and CARB were achieved within 1, 2 and 10 min, respectively. Several aromatic degradation products of DICL, NAPR and CARB were identified by quadrupole time-of-flight mass spectrometer hyphenated to an ultra-high performance liquid chromatograph after preconcentration with off-line solid phase extraction upon irradiation of the UPW matrix spiked with the selected drugs at 254 nm. For several degradation products, chemical structures differing from those previously reported have been proposed. Moreover, acridine has not yet been reported as photodegradation product for DICL. . Almost complete degradation of DICL, NAPR and CARB as well as their degradation products by VUV+PhO in BTWW took place in 5, 10 and 30 min, respectively applying only one 50 cm long photo-reactor and oxygen stream. The efficiency of this technology can be increased by simultaneous application of more photoreactors in a flowing system.

Session: 17, Room: E, at Thu, 09/05/2019 - 15:15 to 15:30
Oral presentation in Advanced oxidation processes
[CEST2019_00518] Degradation of Cylindrospermopsin using Advanced Non-Thermal Plasma Technologies
by Schneider M., Rataj R., Kolb J.F., Bláha L.

The application of non-thermal plasmas in wastewater and air purification received a lot of attention, but their potential application in drinking water treatment has scarcely been investigated. Classified as Advanced Oxidation Processes, plasmas ignited in water or at the air-water interface generate a vast range of reactive species capable of removing water contaminants.
The efficiency to degrade cylindrospermopsin (CYN, cyanobacterial toxin) was compared for six different plasma sources. A spark discharge showed the most energy-efficient degradation, followed by the other investigated systems, which showed similar trends.
Two approaches were selected for further in-depth study of the degradation efficiency and underlying mechanisms. For a follow-up detailed study, a corona-like and a dielectric barrier discharge were selected based on the CYN degradation efficiency, usability of the reactors and plasma-chemistry. For the corona-like plasma, the degradation efficiency increased with increasing voltage and solution pH. After 15 min of plasma treatment at pH ≥ 7.5, degradation of CYN even progressed without further plasma application. The pH-dependency was not observed for the dielectric barrier discharge (DBD), whose degradation efficiency increased with decreasing operating voltage. The corona-like plasma promotes degradation primarily via OH, whereas the DBD produces mainly O3 and NOx.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:00 to 12:15
Oral presentation in Advanced oxidation processes
[CEST2019_00533] Fluoride-free Anodization of Titanium and the Photocatalytic Behaviour of the Produced TiO2 Nanostructures
by Taylor C.M., Mattia D., Wenk J.H.

Current methods for anodizing titania to produce immobilized titanium dioxide (TiO2) photocatalyst require the use of hazardous fluoride electrolytes. A fluoride-free electrolyte anodization method was developed. The electrolytes tested in this study were both bromide- and chloride-based and contained ethylene glycol as an additive. Under optimized anodization times and temperature conditions the alternative electrolytes led to growth of stable immobilized TiO2 layers. Crystal phases and topography of the produced TiO2 layers were characterized using scanning electron microscopy (SEM), X-ray diffraction (XRD) and photoelectron spectroscopy (XPS). Photocatalytic experiments showed that differences in the crystal phases had a strong effect on the degradation of the model aquatic contaminants carbamazepine and phenol. Nitrogen doping using urea made the photocatalyst more efficient by red shifting light absorption from UV into the visible region. The photocatalytic ability of fluoride-free anodized immobilized TiO2 photocatalysts has previously not been investigated. Using electrolytes without fluorine can be a more sustainable and a safer way to produce immobilized TiO2.

Session: 17, Room: E, at Thu, 09/05/2019 - 15:00 to 15:15
Oral presentation in Advanced oxidation processes
[CEST2019_00497] Cavitation Based Advanced Oxidation Processes for Wastewater Treatment – Comparison of Hydrodynamic and Sonocavitation Systems
by Boczkaj G., Gągol M., Fedorov K., Cako E.

Cavitation based advanced oxidation processes (Cav-AOPs), are a promising alternative to currently used wastewater treatment technologies. Amplified interest in this “hot” topic results in increased number of research on several aspects relating to formation of cavitation phenomena and its utilization for wastewater treatment as well as hybrid processes based of application of external oxidants effectively converted to radical species in cavitation conditions. The paper discusses a state of the art of cavitation based AOPs, as well as presents recent developments in this field of our research group. The principles of cavitation combined with AOPs will be presented followed by evaluation of their effectiveness in oxidation of organic contaminants and comparison of hydrodynamic and acoustic cavitation processes used for same type of pollutants. An examples of degraded particular pollutants will include chlorinated and nitro derivatives as well as other emerging environmental pollutants. Applications for disinfection of water will be also addressed. The paper will present also results of studies on degradation of pharmaceuticals as well as pre-treatment of real post-oxidative effluents formed during bitumen production as an examples of possible implementation of cavitation based processes in real industrial scenario.

Session: 11, Room: E, at Thu, 09/05/2019 - 11:45 to 12:00
Oral presentation in Advanced oxidation processes
[CEST2019_00335] Wastewater treatment processes utilizing hydrodynamic cavitation
by Innocenzi V., Prisciandaro M., Veglio F.

In the present work, the potentiality of the hydrodynamic cavitation (HC) for the degradation of organic pollutants from industrial effluents has been studied. Cavitation is a phenomenon of formation, growth, collapse of microbubbles or cavities, in a few milli- to microseconds and releases large magnitude of energy in a short span of time. The main chemical effects of HC are the generation of highly reactive free radicals in the aqueous environment; it is possible to exploit these radicals for the intensification of chemical processes such as degradation of the water pollutants. HC represents an innovative advanced oxidation processes that can replace or be combined with the traditional oxidation processes. Lab experiments have been performed to remove pollutants as dyes (methyl orange) that can be present in textile effluents. In order to investigate the potentiality of HC, the effect of several operative conditions was investigated, as the presence of additivities (hydrogen peroxide and titanium oxides), contaminant concentration and cavitation device (venturi tube and orifice plate). The experiments showed the positive effect of hybrid treatment on pollutant degradation.

Session: 17, Room: E, at Thu, 09/05/2019 - 16:00 to 16:03
Flash presentation in Advanced oxidation processes
[CEST2019_00350] Ozonation, advanced oxidation and hydrodynamic cavitation for removal of persistant pollutants
by Čehovin M., Žgajnar Gotvajn A.

Ozone is commonly used in advanced oxidation processes (AOPs) in combinations with hydrogen peroxide (H2O2) and UV radiation (UV). Hydrodynamic cavitation (HC) has been experimentally proven to result in effects, typical of AOPs. Combinations of AOPs with O3, H2O2 and UV, and HC (with cavitation numbers less than 0.2, generated by various orifice plates and nozzles, with number of passes up to 12) were experimentally assessed on model water, containing organic matter. Various synthetic organic micropollutants (iohexol, diatrizoic acid and metaldehyde with concentrations of 10 μg L–1) were selected as the target compounds. At dosages of O3, H2O2 and UV above 2 mg L–1, 4 mg L–1 and 450 mJ cm–2, respectively, herein applied HC had no beneficial effect on target pollutants removal. At lower dosages of the aforementioned oxidants, HC was able to improve the removal rate of the target pollutants by as much as 15 %. Moreover, in terms of electrical energy consumption, the hybrid process with HC was found to be as efficient per order (90 %) of removal (EEO, kWh m–3 order–1).

Session: 11, Room: E, at Thu, 09/05/2019 - 11:30 to 11:45
Oral presentation in Advanced oxidation processes
[CEST2019_00259] Electrochemical Treatment of Landfill Leachate under Cold Climate Conditions
by Ambauen N.,Hallé C., Meyn T.

This study shows that electrochemical oxidation of landfill leachate (LL) is significantly affected by cold temperatures prevailing in Nordic climate areas. As hypothesized, the degradation of common wastewater parameters (TOC, COD) exhibited lower efficiency when low average temperature (13°C) was applied than compared to room temperature (25°C). At low temperature, 35 % of COD and 64 % of TOC were removed, compared to 69 % of COD and 74 % of TOC removal at high temperature. Electrochemical oxidation of ammonium (NH4) has also been observed, whereas only 1 % was removed at 13°C compared to 11 % at 25°C. In addition, the formation of three hazardous trihalomethanes (THMs) has been confirmed when a high current (7A) was applied, but THMs remained below the quantification limit of 3 ppb at low current (0.3 A). Even though kinetics decrease when cold temperatures are prevailing, electrochemical oxidation is considered still a suitable choice for the treatment of landfill leachate in areas with Nordic climate.

Session: 5, Room: E, at Thu, 09/05/2019 - 10:15 to 10:30
Oral presentation in Advanced oxidation processes
[CEST2019_00227] UV/H2O2 coupled with adsorption for decolorization of dye mixtures in water and phytotoxic effects
by Ortega A.C., Alvarez C.F., Cardona L., Arroyave C., Aristizábal A.

The present study reported the decolorization by UV/H2O2 of three dyes and their binary and ternary mixtures in water, simulating colored effluents of the textile industry. The effect of the initial concentration of H2O2, the initial concentration of dyes and the reaction kinetics in the decolorization of textile dyes in water was studied. The efficiency of decolorization of three treatment processes was compared (UV, H2O2 and UV/H2O2). Moreover, after decolorization of the simulated waters by UV/H2O2 the effluents were then treated by adsorption using a commercial aluminosilicate and a silica gel (waste from industry). The phytotoxicity of the effluents was determined before and after adsorption treatment using the Raphanus sativus bioassay.

Session: 5, Room: E, at Thu, 09/05/2019 - 10:00 to 10:15
Oral presentation in Advanced oxidation processes
[CEST2019_00228] Evaluation of phytotoxic effects and decolorization of simulated and real textile wastewaters by UV/H2O2
by Quiceno L.I., Hernández M., Cardona L., Arroyave C., Aristizábal A.

In the present study textile dyes (Methylene Blue, Eliamine Blue F, Indigo) were used as model pollutants in water (ranging from 5 – 5000 mg/L) and real wastewater containing the Indigo dye was studied. The dyes in solution and the wastewater were treated by UV/H2O2 to study the influence of the type of dye, the initial concentrations of dye, the initial concentration of H2O2, the initial pH of the solution and the irradiation time in the dye decolorization of the treated solutions. The phytotoxic effect in Raphanus sativus of the treated and untreated dyes and wastewater in solution were evaluated.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:33 to 12:36
Flash presentation in Advanced oxidation processes
[CEST2019_00206] Comparative Analysis of Chlorinated Intermediates Formed During Electrochemical and Photo(electro)catalytic Degradation of 4-Ethylphenol in Saline Media
by Brüninghoff R., Van Duijne A., Braakhuis L., Saha P., Jeremiasse A., Mei B., Mul G.

Formation of toxic by-products, such as chlorinated intermediates, is one of the major drawbacks of advanced oxidation processes for saline wastewater treatment. Here a comparative analysis of electrochemical oxidation and photocatalytic degradation of 4-Ethylphenol, a non-chlorinated starting model compound of the group of alkylphenols, is presented. Main intermediates have been identified and quantified for brackish [0.03 mol*L-1] and sea water [0.6 mol*L-1] salt concentrations representative for the salt levels in various industrial effluents. Our comparison indicates that photocatalytic treatment (using TiO2 photocatalysts) might be favorable over electrochemical treatments with Pt or BDD anodes due to the minor role of chlorination and the limited formation of chlorinated compounds in photocatalysis. Finally, using photoelectrochemical degradation an external surface recombination mechanism of photogenerated charge carriers will be presented explaining the absence of chlorinated compounds during photocatalytic wastewater treatment.

Session: 5, Room: E, at Thu, 09/05/2019 - 09:45 to 10:00
Oral presentation in Advanced oxidation processes
[CEST2019_00070] Effect of hydrogen peroxide on caffeine oxidation by sono-Fenton technology
by Villota N., Sardón L., Ferreiro C., Lomas J.M., Camarero L.M.

Oxidation of waters containing 100.0 mg L-1 of caffeine was conducted by a sono-Fenton treatment employing an ultrasound power of 720W at pH=3.0 and T=25°C. The oxidizing action of hydrogen peroxide was studied in a range between [H2O2]0=0-250.0 mM, using iron ratios of 0.7 mol Fe2+/mol C8H10N4O2. The oxidation of caffeine was fitted to second order kinetics, obtaining removals of 98% when dosing 485 mol H2O2/mol C8H10N4O2. During the oxidation, the water acquired a strong brown colour at the same time as there was a strong increase in turbidity and degree of aromaticity. The interaction of (hydro)peroxo-iron complexes with the byproducts of caffeine degradation (1,3,7-trimethyluric acid, theobromine, paraxanthine, theophylline) generated supramolecular structures responsible for this phenomenon, being 116 mol H2O2/mol C8H10N4O2, the relationship that induced colour and aromaticity, while the formation of turbidity was favoured by using 29 and 116 mol H2O2/mol C8H10N4O2.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:39 to 12:42
Flash presentation in Advanced oxidation processes
[CEST2019_00071] Changes of dissolved oxygen during the caffeine oxidation by photo-Fenton
by Villota N., Coralli I.,Lomas J.M.

The aim of this work is to analyse the changes of dissolved oxygen ([DO], mg/L) during the oxidation of caffeine waters by photo-Fenton treatment. The concentration of dosed hydrogen peroxide would be the addition of the stoichiometric [H2O2], which reacts with organic matter ([H2O2]esteq=2.0 mM), plus the concentration in excess of [H2O2]exc that decomposes, generating O2 through radical processes, according to a ratio R=0.8164 mmol H2O2/mg O2). Operating at doses lower than the stoichiometric value [H2O2]0<2.0 mM, O2 is not emitted, as there is no excessive oxidant. Besides, it is verified that the Fe2+ ion is oxidized to Fe3+, with subsequent regeneration to Fe2+. Applying higher doses than the stoichiometric [[H2O2]0>2.0 mM, oxygen is released, and regeneration of Fe3+ to Fe2+does not occur. The highest oxygen generation output is obtained when dosing [Fe]0=10.0 mg/L, conducting at pH=3.0 and 25ºC. The evolution of DO formation is adjusted to zero-order kinetics, the kinetic constant of oxygen generation being kf=29.48 [Fe]0-1.25 (mg O2 L-1 min -1) and oxygen consumption kd=-0.006 [Fe]02.0 + 0.244 [Fe]0-3.7 (mg O2 L-1 min-1).

Session: 11, Room: E, at Thu, 09/05/2019 - 12:15 to 12:30
Oral presentation in Advanced oxidation processes
[CEST2019_00079] Colour changes during the carbamazepine oxidation by photo-Fenton
by Villota N., Qullatein H., Lomas J.M.

Oxidation of waters containing 50.0 mg L-1 of carbamazepine was conducted by a photo-Fenton reagent employing a UV lamp of 150W, at pH=3.0 and T=40°C. The oxidising action of hydrogen peroxide was studied in a range between [H2O2]0=0-15.0 mM. When applying stoichiometric ratios of 2 mol C15H12N2O:20 mol H2O2:1.8 mol Fe2+, the maximum formation of colour (0.381 AU) is promoted. The colour may be generated by by-products of degradation of carbamazepine that have chromophore groups in its internal structure, such as oxo and dioxo-carbazepines, which would generate colour during the first minutes of oxidation, while the formation of acridones would slowly induce colour to the water.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:42 to 12:45
Flash presentation in Advanced oxidation processes
[CEST2019_00064] Effect of iron catalyst on caffeine oxidation by sono-Fenton technology
by Villota N., Sardón L., Ferreiro C., Lomas J.M., Camarero L.M.

Oxidation of waters containing 100.0 mg L-1 of caffeine was conducted by a sono-Fenton treatment employing an ultrasound power of 720W at pH=3.0 and T=25°C. The catalytic action of ferrous ion was studied in a range of [Fe2+]0=0-100.0 mg L-1, using oxidant ratios of [H2O2]0=250.0 mM. The oxidation of caffeine was fitted to second order kinetic model, with the oxidation kinetic constant showing a linear dependence with iron dosage. During oxidation, the water acquired yellow-brown colour, along with an increase of turbidity and aromaticity degree. This is due to byproducts formation of uric acid-derived that has strongly aromatic structures that contain chromophore groups. Iron could give rise to a reaction mechanism with organic matter through the formation of (hydro)peroxo iron complexes. The molar ratio of 1 mol Fe2+: 0.5 mol C8H10N4O2 : 250 mol H2O2 : 720W promotes the formation of coloured species that generate high turbidity in the water.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:36 to 12:39
Flash presentation in Advanced oxidation processes
[CEST2019_00014] Fenton reagent in combination with UV light and ultrasound waves applied for caffeine oxidation
by Villota N., Lomas J.M.

The oxidation of aqueous caffeine solutions ([Ca]0=100.0 mg L-1) was analyzed, operating at pH=3.0 and 25ºC using different AOPs, which combine the Fenton reagent ([H2O2]0=15.0 mM and [Fe2+]0=20.0 mg L-1) with low power UV light (15W,), medium (150W), and high (720 W). The Fenton reagent, combined with 150W UV light, was the most energetic treatment, proving that at 20 min it completely degrades caffeine and 80% of the water aromaticity. This hard oxidative process is accompanied by a high oxygen consumption, up to concentrations of [DO]=0.9 mg L-1 at the time when the caffeine contained in the water is completely degraded. On the other hand, 150W UV light is the only treatment capable of decreasing the concentration of total solids dissolved in water, according to a ratio of 0.0035 min-1. US waves allow degrading caffeine by 35%. This treatment leads to the emission of high oxygen concentrations ([DO]=20.0 mg L-1), which subsequently decreases along time. The UV lamp of 15W allows degrading caffeine by 12%, but does not affect the rest of the parameters analyzed.

Session: 11, Room: E, at Thu, 09/05/2019 - 12:30 to 12:33
Flash presentation in Advanced oxidation processes
[CEST2019_00015] US/H2O2 combined technology applied to the paracetamol oxidation
by Villota N., Lomas J.M.

This study analyzes the colour acquired by oxidizing paracetamol aqueous samples through the combined US/H2O2 technology. When operating with only the action of the waves [US]=1.0 kWh/mmol C8H9NO2, the water acquires progressively hue according to a ratio of 0.0004 AU/min, with a degradation output of 14%. Working under these conditions, the presence of hydroquinone, muconic acid and formic acid is evaluated. Colour formation presents a maximum intensity when water containing paracetamol is degraded using molar ratios of 1.5 mol H2O2/mol C8H9NO2. This dosage leads to the formation of benzoquinone, as well as muconic and formic acids, reaching an efficiency of 30%. Oxidazing with 6.0 mol H2O2/mol C8H9NO2, colour formation occurs slowly during the first hour of reaction, leading to the formation of benzoquinone, hydroquinone, acetamide, phoroglucinol and formic and muconic acids. This last one presents a molecular structure that is prone to reacting with other species that are present in the system forming complexes.

Session: 5, Room: E, at Thu, 09/05/2019 - 09:30 to 09:45
Oral presentation in Advanced oxidation processes