Person: Gutiérrez Sánchez, Pablo
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First Name
Pablo
Last Name
Gutiérrez Sánchez
Affiliation
Universidad Complutense de Madrid
Faculty / Institute
Ciencias Químicas
Department
Ingeniería Química y de Materiales
Area
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3 results
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Item Extraction of neonicotinoid pesticides from aquatic environmental matrices with sustainable terpenoids and eutectic solvents(Separation and Purification Technology, 2022) Gutiérrez Sánchez, Pablo; Navarro, Pablo; Álvarez Torrellas, Silvia; García, Juan; Larriba Martínez, MarcosThe potential environmental impact and adverse effects of the occurrence of pesticides in the aquatic environment have raised great social and political concern, leading to their control by means of several regulations, such as the European Directive 98/83/EC. In this regard, the three neonicotinoid pesticides analyzed in this work (acetamiprid, imidacloprid, and thiamethoxam) have been included in the surface water European Watch Lists under the Water Framework Directive. This research proposes the use of terpenoid-based solvents for the extraction of the three emerging contaminants previously mentioned. An initial screening of the extraction solvents was carried out through the COSMO-RS methodology, selecting the most favourable pure terpenes, eutectic terpenoid-based and conventional solvents. Furthermore, relevant issues were experimentally analyzed, such as extraction in more realistic multicomponent mixtures together with key parametric studies covering operating temperature and matrix influence. Carvacrol, a pure terpenoid not applied before as an extraction solvent of pesticides, has been revealed as an effective and sustainable substitute for conventional solvents for the first time to the best of our knowledge. Specifically, carvacrol exhibited overall extraction yields of around 97.5 % from a river water matrix at a volumetric S/F ratio of 0.1 and 303.2 K. High extraction yields from river water matrices regardless of temperature pointed to the potential of this solvent for a wide range of industrial application.Item Efficient removal of antibiotic ciprofloxacin by catalytic wet air oxidation using sewage sludge-based catalysts: degradation mechanism by DFT studies(Journal of Environmental Chemical Engineering, 2023) Gutiérrez Sánchez, Pablo; Álvarez Torrellas, Silvia; Larriba Martínez, Marcos; Gil, María Victoria; Garrido Zoido, Juan Manuel; García Rodríguez, JuanIn this work, the sewage sludge-derived activated carbon (SAC) loaded with iron nanoparticles (FeSAC) showed a highly effective catalytic activity in the degradation of the antibiotic ciprofloxacin by the CWAO reaction. The properties of FeSAC catalyst were studied by using N2 adsorption-desorption measurements at 77 K, scanning electron microscopy, X-ray fluorescence spectroscopy, X-ray photoelectron spectroscopy and thermogravimetric analysis. The CWAO reaction was evaluated at different temperatures (120–140 ºC), total pressure (10–30 bar) and catalyst doses (0.1–0.7 g/L) in a batch reactor. In this regard, temperature and catalyst dosage showed a significant impact on the removal of the tested antibiotic. By using a catalyst dose of 0.7 g/L, ciprofloxacin degradation and CO2 selectivity were higher than 99 % and 60 %, respectively, and were achieved within two hours at 140 °C and 20 bar. The loss of the active phase (Fe) of the catalyst in the reaction medium was measured, obtaining negligible values (less than 24 ppb). This catalyst showed high stability under the tested reaction conditions. In addition, a potential equation was proposed to correctly describe the evolution of ciprofloxacin degradation. The calculated activation energy of the CWAO process was 53.8 kJ/mol. Additionally, Density Functional Theory (DFT) calculations were performed to illustrate the degradation mechanism of ciprofloxacin, where the electronic energies indicated the compounds that are most difficult to degrade by CWAO. Finally, a proof of concept using an environmentally-relevant matrix was carried out, verifying the technical feasibility of the synthesized catalyst for its application with more complex matrices, consecutive reaction cycles and at a low treatment costItem Influence of transition metal-based activating agent on the properties and catalytic activity of sewage sludge-derived catalysts. Insights on mechanism, DFT calculation and degradation pathways(Journal of Molecular Liquids, 2023) Gutiérrez Sánchez, Pablo; Álvarez Torrellas, Silvia; Larriba Martínez, Marcos; Gil, María Victoria; Garrido Zoido, Juan Manuel; García Rodríguez, JuanResearch studies combining the detailed physicochemical properties' analysis, the catalytic activity in different real aqueous matrices, the proposal of degradation mechanisms and the stability of the intermediates/by-products by means of the Density-functional theory (DFT) are scarce. Therefore, this work gives a step forward in the field of circular economy and the removal of emerging pollutants such as the antibiotic ciprofloxacin, covering all the previously aspects mentioned, using four iron and nickel-based catalysts from two different sewage sludge. Experimental results revealed a significant influence of both the source of the sewage sludge and the activating agent used (iron chloride, nickel chloride and a mixture of both) on the physicochemical properties of the materials and, hence, on their catalytic activity. FTIR studies and chemical composition evidenced that the use of this biomass precursor leads to the generation of a wide variety of functional groups and heteroatoms in the synthesized catalyst structure. Moreover, they showed a combination of Type I-IV isotherms with H3-H4 type hysteresis loops, being mainly mesoporous materials and exhibiting a moderate microporosity except when nickel chloride was used solely as activating agent. The carbonaceous materials reached ciprofloxacin adsorption capacities in the range of 40.4–73.9 mg/g. The use of nickel chloride showed the lowest adsorption contribution and catalytic activity. The bimetallic catalyst (synthesized from a mixture of iron and nickel chloride) showed slightly higher catalytic activity than that found for the iron catalyst, but the metal leaching was also considerably higher. Consequently, the use of iron chloride solely as activating agent seems to be the better alternative, achieving a maximum ciprofloxacin removal around 99.7 % and an iron leaching concentration into the reaction medium of 0.48–0.61 mg/L. The main degradation pathways of ciprofloxacin were proposed according to the detection of LC-MS intermediates and DFT calculation, indicating the most likely areas of attack of reactive species on atoms with a high Fukui index (f0)