Browsing by Subject "Heterogeneous photocatalysis"

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    Decline of fluroxypyr and triclopyr residues from pure, drinking and leaching water by photo-assisted peroxonation
    (Elsevier, 2020) Pérez-Lucas, Gabriel; Aliste, Marina; Vela, Nuria; Garrido, Isabel; Fenoll, José; Navarro, Simón; Química Agrícola, Geología y Edafología
    Groundwater is a source for drinking water in many countries, and its use is seriously threatened by the leaching of agrochemicals through the soil. With this aim, the oxidation of triclopyr and fluroxypyr in water was investigated at lab-scale using heterogeneous photocatalysis and photo-assisted ozonation combined with hydrogen peroxide H2O2 (peroxone process). For both herbicides, the order of effectiveness of the photo-assisted treatments in pure water were as follows: O3/H2O2>ZnO/Na2S2O8>TiO2/Na2S2O8. Comparing the three types of water, the rate constants through peroxone/UV process were in the order: Pure > Drinking > Leaching water, according to the complexity of the matrix. After two hours of treatment, fluroxypyr was completely removed from pure water, while 90 % and 55 % of its initial mass were removed from drinking and leaching water, respectively. On the other hand, the degradation of triclopyr was significantly slower. In this case, after two hours of illumination the complete degradation was not reached in any case. Owing to the generation of hydroxyl radicals (HOradical dot) the water treatment with O3/H2O2/UV can be considered as an eco-friendly technology, although the substances present in the matrix, mainly in leaching water, can scavenge HOradical dot decreasing the photooxidation rate of both herbicides.
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    Photocatalytic oxidation of carbamazepine in water using TiO2 with LED lamps: Study of intermediate degradation products by liquid chromatography mass spectrometry after dispersive liquid–liquid microextraction
    (Elsevier, 2024-07-01) Martínez Escudero, Carmen Maria; Garrido, Isabel; Contreras, Fulgencio; Hellín Pilar; Flores Pilar; Arroyo Manzanares, Natalia; Viñas López-Pelegrin, Pilar; Campillo Seva, Natalia; Fenoll, José; León Morán, Lixy Olinda; Química Analítica
    An evaluation of carbamazepine (CBZ) photolysis degradation in water under different experimental conditions is here presented for wastewater detoxification. For this, an analytical methodology based on a green sample treatment procedure and liquid chromatography with mass spectrometry (LC-MS) using both quadrupole time-of-flight (QTOF) and triple quadrupole (QqQ) analyzers has been proposed. Dispersive liquid–liquid microextraction (DLLME) provides high preconcentration efficiency for the pharmaceutical emerging contaminant, allowing its monitorization and that of its transformation products (TPs) with high sensitivity. Subsequently, the established analytical method has been applied to study of behaviour of CBZ and its TPs generated in water during photolysis treatments in the presence and the absence of the catalyst TiO2 Degussa P25 and irradiating with ultraviolet (UV) and visible (Vis) light emitting diode (LED) lamps as light source. Nineteen TPs were tentatively identified. A significantly higher degradation rate of CBZ and its TPs was observed with the use of UV-LED lamps during the heterogeneous photocatalysis based treatment.
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    Photodecomposition of antibiotics and their transformation products in wastewaters using ZnO and TiO2 with LED lamps
    (Elsevier, 2024-09-01) Martínez Escudero, Carmen Maria; Garrido, Isabel; Contreras, Fulgencio; Hellín, Pilar; Flores, Pilar; Arroyo Manzanares, Natalia; Campillo Seva, Natalia; Pastor Belda, Marta; Viñas López-Pelegrin, Pilar; Fenoll, José; León Morán, Lixy Olinda; Química Analítica
    This work presents a study of the behavior of three antibiotics (erythromycin (ERY), clarithromycin (CLR) and sulfadiazine (SFZ)) and their transformation products (TPs), generated after photolytic and photocatalytic (TiO2 and ZnO) treatments, in wastewater irradiated with ultraviolet (UV) light emitting diode (LED) lamps as light source. For this, an analytical methodology for the antibiotics and their TPs was developed. Thus, samples were treated by salting-out assisted liquid–liquid extraction (SALLE) and identification and quantification was carried out by liquid chromatography with mass spectrometry (LC-MS) using quadrupole time-of-flight (QTOF) and triple quadrupole (QqQ) analyzers, respectively. The results revealed the presence of 14, 13 and 5 TPs of ERY, CLR and SFZ, respectively, being found in wastewaters spiked with the antibiotics during photo-oxidation treatment. Subsequently, the established analytical method was also applied, in a real case, to study of behavior of these pharmaceuticals (0.2 mg L-1) and their TPs generated in wastewater during a photocatalytic treatment. In this case, 13, 11 and 2 TPs were tentatively identified ERY, CLR and SFZ, respectively. In addition, the photocatalytic treatment using TiO2 exhibited higher degradation rate than photocatalytic treatment using ZnO. The ECOSAR programme was used to estimate the potential ecotoxicity of the identified TPs. The results showed a potential hazard of SFZ, CLR, ERY and some of their TPs to aquatic organisms. Furthermore, some of the identified TPs were found to be more toxic than their parent compounds.
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    Reclamation of aqueous waste solutions polluted with pharmaceutical and pesticide residues by biological-photocatalytic (solar) coupling in situ for agricultural reuse.
    (Elsevier, 2022) Pérez-Lucas, Gabriel; El Aatik, Aldo; Aliste, Marina; Hernández, Virginia; Fenoll, José; Navarro, Simón; Química Agrícola, Geología y Edafología
    This work focuses on the detoxification of aqueous waste solutions polluted with 24 emerging pollutants (13 pharmaceuticals and 11 pesticides) using a coupled biological-photocatalytic facility under natural sunlight for use in crop irrigation. The polluted wastewater (urban, agricultural, and industrial) processed by conventional wastewater treatment plants is in some cases insufficient to reach the degree of purity required. This concern is of particular interest, especially in areas where a low rainfall pattern provides insufficient water resources to meet the demands caused by agriculture, which requires increased reuse of wastewater effluents. For this purpose, polluted water was first subjected to biological treatment followed by a photocatalytic process using the tandem TiO2/Na2S2O8. Residues of pharmaceuticals and pesticides were isolated by solid phase extraction (SPE) and analysed by HPLC-QqQ-MS2. A notorious removal of pharmaceuticals was observed after biological treatment (average removal = 78%), except for diclofenac (31%) and carbamazepine (1%). In a contrary way, biodegradation of pesticides was inconspicuous (average removal = 48%) due to their recalcitrant properties. However, all compounds were rapidly degraded during the photocatalytic treatment because the fluence (H) required to obtain 90% degradation (H90) was<470 kJ m−2 for the most persistent pollutant (terbuthylazine). Single first order kinetic model satisfactorily explained the photooxidation of all micropollutants. Therefore, solar heterogeneous photocatalysis is presented as a promising technology to be incorporated as a tertiary process in wastewater treatment plants to remove biorecalcitrant pollutants. This implementation could be interesting especially in arid and semi-arid areas characterised by water scarcity but receiving many hours of sunshine per year, where a high percentage of reclaimed water is used for crop irrigation.