http://hdl.handle.net/10498/6832 Thu, 05 Nov 2026 06:57:03 GMT 2026-11-05T06:57:03Z http://hdl.handle.net/10498/40480 A nontarget search for organic micropollutants in suspended particulate matter and sediments of Admiralty Bay, Antarctic Peninsula Souza, A.C.; Combi, T.; Martins, C.C.; Lourenço, R.A.; Pintado Herrera, Marina Guadalupe Anthropogenic contamination in remote polar environments is a critical concern, demanding comprehensive assessment methods that go beyond targeted analysis. This study aimed to characterize the broad scope of organic contaminants in Admiralty Bay, a scientifically significant area in the Antarctic Peninsula, by applying a dual-matrix, nontarget screening approach. Surface sediments were analyzed by GC-HRMS and LC-HRMS, while suspended particulate matter (SPM) was analyzed only by GC-HRMS. Both analytical techniques were coupled with Quadrupole Time-of-Flight (QTOF) high-resolution mass spectrometry. The screening initially detected over 10,000 chemical features in SPM samples and over 17,000 in sediments (Level 5). After data processing, 48 compounds were tentatively identified (Levels 2 and 3) in the SPM samples. For the sediment samples, 54 compounds were identified by GC analysis and 19 by LC analysis at the same confidence levels. Most of the features detected were classified as natural compounds. High-confidence identification using analytical standards (Level 1) confirmed the presence of 6 anthropogenic contaminants in SPM and 5 in sediments, including flame retardants, personal care products, and polycyclic aromatic hydrocarbons. The profiles in SPM and sediment were distinct, highlighting that SPM reflects dynamic, current pollution while sediments represent a recent deposition. This dual-matrix approach provides a more realistic contamination assessment, delivering essential data for environmental management under the Madrid Protocol. Thu, 01 Jan 2026 00:00:00 GMT http://hdl.handle.net/10498/40480 2026-01-01T00:00:00Z http://hdl.handle.net/10498/40000 Insights into the stability and thermal properties of WSe2-based nanofluids for concentrating solar power prepared by liquid phase exfoliation Martínez Merino, Paloma; Sánchez-Coronilla, Antonio; Alcántara Puerto, Rodrigo; Martín, Elisa I.; Navas Pineda, Francisco Javier Nanofluids are considered the new generation of heat transfer fluids thanks to their improved thermophysical properties compared with conventional fluids. However, little research has been performed into the thermal properties, stability and preparation of nanofluids based on two-dimensional nanostructures. In this paper, we discuss the preparation of nanofluids based on 2D-WSe2 nanostructures prepared by liquid phase exfoliation applying two different sources of ultrasound. The base fluid for these nanofluids is a eutectic mixture of biphenyl and diphenyl oxide used as a heat transfer fluid in the parabolic trough collectors of concentrating solar power plants. The 2DWSe2-based nanofluids were characterized for their stability and thermal properties. Treatment with ultrasonic tip resulted in remarkable improvements in the exfoliation of the nanomaterial and stable nanofluids. At a molecular level, periodic-DFT calculations were performed to understand the stability of the 2D-WSe2 -based nanofluids from the perspective of the arrangement of the surfactant molecules around the WSe 2 nanosheets. The results suggest that the most favoured interaction with the WSe2 sheets occurs through the hydroxyl terminal group of Triton-X. The hydrogen bond interaction between the H atom of the -OH group of Triton-X and three Se atoms on the surface of the sheet plays a stabilizing role in the system. Thus, the arrangement of the surfactant must facilitate the exfoliation of the WSe 2 sheets. Furthermore, WSe 2 nanosheets were found to improve the thermal conductivity by up to 39% and the specific heat by up to 9.3%, resulting in an increase in the heat transfer of up to 26%. The results of this study have revealed the great potential of 2D-WSe2 based nanofluids as heat transfer fluids in CSP plants. 10.1016/J.MOLLIQ.2020.114333 Wed, 01 Jan 2020 00:00:00 GMT http://hdl.handle.net/10498/40000 2020-01-01T00:00:00Z http://hdl.handle.net/10498/39999 WSe2 nanowires-based nanofluids for concentrating solar power Navas, Javier; Martínez Merino, Paloma; Alcántara Puerto, Rodrigo; Navas Pineda, Francisco Javier Tungsten selenide belongs to the family of inorganic compounds denominated transition metal dichal- cogenides (TMDCs). There is emerging interest in these compounds in the field of optoelectronics, catalysis, sensing or energy storage, among others. Most works focus on the use of these materials in their 2D form but there is scarce research on the study of TMDCs nanomaterials with one-dimensional morphology. In this work, we explore the thermophysical properties of nanofluids based on 1D-WSe2 nanostructures with the aim of studying the feasibility of these nanofluids as heat transfer fluids in concentrating solar power plants. In this respect, nanofluids with a high heat transfer rate could increase the thermal efficiency of solar power plants, which would reduce the energy dependence on fossil fuels. Nanofluids of 0.02 wt%, 0.05 wt% and 0.10 wt% WSe2 concentrations have been prepared by the two-step method considering a thermal fluid used in solar power plants as the base fluid. The results of extinction coefficient evolution, z potential and particle size in suspension show a high colloidal stability over time of the prepared nano fluids mainly because of the high aspect ratio of the 1D-WSe2 nanomaterial. Additionally, the one-dimensionality and length of the synthesized nanowires favors the transport of heat in controlled directions, obtaining increases in thermal conductivity with respect to the base fluid of up to 16.8% in the highest concentration nanofluid. Improvements in isobaric specific heat of up to 15.7% and heat transfer of up to 20.8% compared to the base fluid have also been found. The results of this paper provide evidence that the presence of WSe2 nanowires induces increases in the thermal properties of the fluid commonly used in concentrating solar power plants without inducing agglomeration or sedimentation problems. Therefore, the nanofluids based on 1D-WSe2 nanostructures prepared in this work have a high potential to be used as heat transfer fluids in concentrating solar power plants based on parabolic trough collectors. 10.1016/j.mtchem.2022.101323 Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/10498/39999 2023-01-01T00:00:00Z http://hdl.handle.net/10498/39542 Artificial Sweeteners in Aquatic Ecosystems: Occurrence, Sources and Effects Fernandez, Ronield; Ojito, Sheila; Pájaro, Valerie; Gutiérrez, Camilo; Bolívar-Anillo, Hernando José; Hampel, Miriam; Anfuso Melfi, Giorgio The growing consumption of synthetically manufactured sugar substitutes, coupled with the lack of adequate national and international regulations, has led to the presence of various compounds, in different environmental matrices. Within this group, artificial sweeteners, despite their prevalence in mass consumption products, are one of the least studied pollutants. The high consumption of artificial sweeteners, together with the low efficiency of wastewater treatment plants, facilitates their detection in various aquatic ecosystems at concentrations ranging from ng to µg L−1. These concentrations have shown to generate adverse effects on the organisms that inhabit these aquatic ecosystems. The main objective of this review is to provide updated information on the global consumption of sweeteners, reported concentrations in various environmental matrices, and, in particular, the effects of exposure to these compounds on aquatic organisms. Sat, 01 Nov 2025 00:00:00 GMT http://hdl.handle.net/10498/39542 2025-11-01T00:00:00Z