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Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] An innovative bulky photocatalyst for water decontamination has been developed. The semiconductor (TiO2) is homogeneously distributed in an aggregating material through the whole piece. This design prevents the activity reduction usually observed in supported catalysts due to the loss of the photoactive layer, and facilitates its recovery for an easy reuse, which is a recurrent problem dealing with nanoparticles. The photocatalyst combines the excellent properties of TiO2 with those of a natural clay, which serves as binder, slows down the phase transition of anatase to rutile upon calcination, and has a synergetic function. The photocatalyst has been prepared in the form of small pellets with an Ecuadorian clay and TiO2 in the commercial form of P25 by evenly dry mixing, forming a paste with water, and subsequent extrusion, drying and calcination at 600 °C. The photodegradation of phenol, as a model pollutant, has been achieved by using this aggregate material in a flow reactor with artificial UVA-Vis radiation, and reused without any significant loss of activity. The photocatalyst showed an optimum activity at a 40% clay / 60% P25 ratio, while higher calcination temperatures had a negative effect on its performance. This research has received funds from the Spanish Ministerio de Ciencia e Innovación [Project PID2021-127898OB-I00], and the regional government Xunta de Galicia [GPC project ED431B 2020/52], to finance a contract to DRR. Funding for open access charge: Universidade da Coruña/CISUG. DRR also acknowledges UDC for a Margarita Salas contract and SDA acknowledges UTPL for financial support for pursuing PhD studies at UDC Xunta de Galicia; ED431B 2020/52

Financiado para publicación en acceso aberto: Universidade da Coruña/CISUG [Abstract] The removal of emerging pollutants from municipal wastewater was studied for the first time using a three-step pilot-scale system: 1) hybrid digester (HD) as first step, 2) subsurface vertical flow constructed wetland (VF) as second step, and 3) photodegradation (PD) unit as third step or post-treatment. The HD and VF units were built and operated in series with effluent recirculation at pilot scale. For the PD post-treatment, three alternatives were studied at lab-scale, i) UVC irradiation at 254 nm (0.5 h exposure time), ii) UVA irradiation at 365 nm using a TiO2-based photocatalyst and iii) sunlight irradiation using a TiO2-based photocatalyst, the last two for 1 and 2 h. Alternative iii) was also tested at pilot-scale. Degradation of nine compounds was evaluated: acetaminophen (ACE), caffeine (CAF), carbamazepine (CBZ), ketoprofen (KET), ibuprofen (IBU), diclofenac (DCL), clofibric acid (ACB), bisphenol A (BPA), and sotalol (SOT). Overall, the HD-VF-UVC system completely removed (>99.5 %) ACE, CAF, KET, IBU, DCL and ACB, and to a lesser extent SOT (98 %), BPA (83 %) and CBZ (51 %). On the other hand, the HD-VF-UVA/TiO2 system (at 2 h) achieved >99.5 % removal of ACE, CAF, KET, IBU and DCL while ACB, BPA, CBZ and SOT were degraded by 83 %, 81 %, 78 % and 68 %, respectively. Working also at 2 h of exposure time, in summer conditions, the HD-VF-Sol/TiO2 system achieved >99.5 % removal of ACE, CAF, KET, IBU, DCL and ACB, and to a minor extent BPA (80 %), SOT (74 %) and CBZ (69 %). Similar results, although slightly lower for SOT (60 %) and CBZ (59 %), were obtained in the pilot sunlight plus TiO2 catalyst unit. However, the use of sunlight irradiation with a TiO2-based photocatalyst clearly showed lower removal efficiency in autumn conditions (i.e., 47 % SOT, 31 % CBZ). This research was funded by the Spanish Ministerio de Economía y Competitividad through project CTQ2015-71238-R (MINECO/FEDER), and the Xunta de Galicia (project GPC ED431B 2020/52 and project GPC ED431B 2019/44), respectively. Funding for open access charge: Universidade da Coruña/CISUG Xunta de Galicia; GPC ED431B 2020/52 Xunta de Galicia; GPC ED431B 2019/44

Plastic debris is widespread in freshwater ecosystems, but a rigorous assessment of its global distribution has been hindered by a lack of comprehensive and comparable data. We performed the first standardized global survey of lakes to assess the quantity and type of plastics (>250μm). We included 38 lakes located in 23 different countries distributed across five continents, spanning different environmental gradients and varying levels of anthropogenic stress. All samples were collected by horizontal trawling of a plankton net and subsequently treated with hydrogen peroxide. We identified 9425 plastic particles, which were classified based on shape, color, and size. Polymer identification was carried out using Raman micro-spectroscopy. Our results showed that the concentration of plastics spanned four orders of magnitude (10-3-101 particles/m3). Fibers (49%) and fragments (41%) were the most frequently detected particles, suggesting a secondary origin of plastic contamination. The most commonly identified polymers were polyester (30%), polypropylene (20%), and polyethylene (16%), which are widely used in short life-cycle products and account for the majority of global plastic production. Further, we found that urban-related attributes of lakes/watersheds influenced the occurrence and type of plastics in lentic systems and larger and deeper lakes with higher retention times are accumulating plastic debris at higher concentrations. info:eu-repo/semantics/publishedVersion

The supramolecular recognition of closo,closo‐[B21H18]− by cyclodextrins (CDs) has been studied in aqueous solution by isothermal titration calorimetry and nuclear magnetic resonance spectroscopy. These solution studies follow up on previous mass‐spectrometric measurements and computations, which indicated the formation and stability of CD ⋅ B21H18 − complexes in the gas phase. The thermodynamic signature of solution‐phase binding is exceptional, the association constant for the γ‐CD complex with B21H18 − reaches 1.8×106 M−1, which is on the same order of magnitude as the so far highest observed value for the complex between γ‐CD and a metallacarborane. The nature of the intermolecular interaction is also examined by quantum‐mechanical computational protocols. These suggest that the desolvation penalty, which is particularly low for the B21H18 − anion, is the decisive factor for its high binding strength. The results further suggest that the elliptical macropolyhedral boron hydride is another example of a CD binder, whose extraordinary binding affinity is driven by the chaotropic effect, which describes the intrinsic affinity of large polarizable and weakly solvated chaotropic anions to hydrophobic cavities and surfaces in aqueous solution., High affinity! The [B21H18]− ion is a new example of a superchaotropic anion that forms a stable host–guest complex with cyclodextrins in aqueous solution.

[Abstract] The determination of reaction pathways and identification of products of pollutants degradation is central to photocatalytic environmental remediation. This work focuses on the photocatalytic degradation of the herbicide Imazapyr (2-(4-methyl-5-oxo-4-propan-2-yl-1H-imidazol-2-yl) pyridine-3-carboxylic acid) under UV-Vis and visible-only irradiation of aqueous suspensions of CaᵪMnOᵧ-TiO₂, and on the identification of the corresponding degradation pathways and reaction intermediates. CaᵪMnOᵧ-TiO₂ was formed by mixing CaᵪMnOᵧ and TiO₂ by mechanical grinding followed by annealing at 500 °C. A complete structural characterization of CaᵪMnOᵧ-TiO₂ was carried out. The photocatalytic activity of the hetero-nanostructures was determined using phenol and Imazapyr herbicide as model pollutants in a stirred tank reactor under UV-Vis and visible-only irradiation. Using equivalent loadings, CaᵪMnOᵧ-TiO₂ showed a higher rate (10.6 μM·h⁻¹) as compared to unmodified TiO₂ (7.4 μM·h⁻¹) for Imazapyr degradation under UV-Vis irradiation. The mineralization rate was 4.07 μM·h⁻¹ for CaᵪMnOᵧ-TiO₂ and 1.21 μM·h⁻¹ for TiO₂. In the CaᵪMnOᵧ-TiO₂ system, the concentration of intermediate products reached a maximum at 180 min of irradiation that then decreased to a half in 120 min. For unmodified TiO₂, the intermediates continuously increased with irradiation time with no decrease observed in their concentration. The enhanced efficiency of the CaᵪMnOᵧ-TiO₂ for the complete degradation of the Imazapyr and intermediates is attributed to an increased adsorption of polar species on the surface of CaᵪMnOᵧ. Based on LC-MS, photocatalytic degradation pathways for Imazapyr under UV-Vis irradiation have been proposed. Some photocatalytic degradation was obtained under visible-only irradiation for CaᵪMnOᵧ-TiO₂. Hydroxyl radicals were found to be main reactive oxygen species responsible for the photocatalytic degradation through radical scavenger investigations. This research received external funding from the British Council under the STREAM-MENA Institutional Links Scheme Grant number 278072873. This is a collaboration between Ulster University (UK), Technion Institute (Israel) and Rabat University (Morocco). MC acknowledges support from Ministerio de Economía y Competitividad (Spain) through project CTQ2015-71238-R (MINECO/FEDER). AS would like to acknowledge the financial support received from Ulster University (UK) through the VCRS scholarship. PS would like to acknowledge funding from Invest Northern Ireland for the BioDevices project British Council; 278072873

The majority of microplastic research has focused on seawater, with fewer than 4% of microplasticsrelated studies occurring on freshwaters. The limited available information suggests that the abundance of microplastics in freshwaters is often as high or even higher than marine environments. However, comprehensive investigations on occurrence and fate of microplastics in freshwaters are scarce and highly fragmented, partly because detection and identification of microplastic particles is rather complex. In addition, up to now, harmonized and standardized protocols for the sampling and analysis of microplastics in freshwaters do not exist, and studies with different research aims and hypotheses often report unstandardized results, making comparison among studies difficult. In the present study, we performed the first global standardized sampling and analysis effort to investigate the occurrence and distribution of microplastics in surface water of lakes and reservoirs with different anthropogenic impacts. Participants aim to collect water samples of freshwater systems with different features (e.g., area, depth, thermal behavior, watershed), following a common protocol. This 18 establishes the collection of samples by horizontal trawling of a plankton net and, after treatment with hydrogen peroxide, the polymer identification through micro-Raman spectroscopy. This GLEON project will allow obtaining comparable data about microplastic contamination in different freshwater systems around the globe. With this global dataset, our goals are to determine whether a relationship exists between the abundance of microplastics and the waterbody/watershed attributes and understand which factors are likely to influence the occurrence of microplastics in surface water of lentic systems. info:eu-repo/semantics/publishedVersion

[Abstract] Photocatalyzed degradation of phenol in aqueous solution over surface impregnated TiO₂ (M = Cu, Cr, V) under UV-Vis (366 nm) and UV (254 nm) irradiation is described. Nanosized photocatalyts were prepared from TiO₂-P25 by wet impregnation, and characterized by X-ray diffraction, X-ray fluorescence, transmission electron microscopy, UV-Vis diffuse reflectance spectroscopy, Raman spectroscopy, and adsorption studies. No oxide phases of the metal dopants were found, although their presence in the TiO₂-P25 lattice induces tensile strain in Cu-impregnated TiO₂-P25, whereas compressive strain in Cr- and V-impregnated TiO₂-P25. Experimental evidences support chemical and mechanical stability of the photocatalysts. Type IV N₂ adsorption–desorption isotherms, with a small H3 loop near the maximum relative pressure were observed. Metal surface impregnated photocatalysts are mesoporous with a similar surface roughness, and a narrow pore distribution around ca. 25 Å. They were chemically stable, showing no metal lixiviation. Their photocatalytic activity was followed by UV-Vis spectroscopy and HPLC–UV. A first order kinetic model appropriately fitted the experimental data. The fastest phenol degradation was obtained with M (0.1%)/TiO₂-P25, the reactivity order being Cu > V >> Cr > TiO₂-P25 under 366 nm irradiation, while TiO₂-P25 > Cu > V > Cr, when using 254 nm radiation. TOC removal under 366 nm irradiation for 300 min showed almost quantitative mineralization for all tested materials, while 254 nm irradiation for 60 min led to maximal TOC removal (ca. 30%). Photoproducts and intermediate photoproducts were identified by HPLC–MS, and appropriate reaction pathways are proposed. The energy efficiency of the process was analysed, showing UV lamps are superior to UVA lamps, and that the efficiency of the surface impregnated catalyst varies in the order Cu > V > Cr. This research was partially supported by the Group of Chemical Reactivity & Photoreactivity at University and funded by the Spanish Ministerio de Economía y Competitividad through project CTQ2015-71238-R (MINECO/FEDER), and the regional government Xunta de Galicia (Project Grupo Potencial Crecemento (GPC) ED431B 2017/59), respectively Xunta de Galicia; ED431B 2017/59

Apesar da existência da Diretiva Quadro da Água, tem-se prestado mais atenção à quantidade de água disponível do que à sua qualidade. Atualmen-te, os sistemas aquáticos estão sujeitos a um cocktail de numerosos contami-nantes, que chega através dos esgotos, da deposição atmosférica, das escor-rências agrícolas, urbanas e rodoviárias, podendo por em risco não só o seu funcionamento, mas também a qualidade da água e a saúde humana. Estes compostos estão presentes numa grande quantidade de bens de consumo (fármacos, produtos de higiene pessoal, detergentes, fitofármacos, vestuário, material eletrónico, plásticos…). A sua gestão ambiental é complexa, porque muitos não estão regulamentados, não são biodegradáveis, não se conhece o seu comportamento em sinergia com outros, circulam entre todos os com-partimentos dos ecossistemas e podem transformar-se noutros compostos mais ou menos tóxicos. Uma vez que este tipo de contaminação não tem efei-tos visíveis no imediato, só é detetada quando existe monitorização orienta-da para averiguar a sua presença. Por outro, lado apesar da existência de tecnologias promissoras na remoção destes contaminantes, não existe uma metodologia que os elimine de forma universal. Na hipótese de acumulação de uma ou mais destas substâncias no ambiente natural, em particular nas massas de água destinadas ao consumo humano, a sociedade enfrentaria um problema de máxima urgência e para o qual, atualmente, não existe solução. Na presente comunicação abordar-se-á o panorama ambiental resultante da existência deste grande número de contaminantes nos sistemas aquáticos. Também serão elencados os comportamentos que, se adotados por todos nós, poderão mitigar de forma significativa este complexo problema ambiental. Currently, aquatic systems are subject to a cocktail of numerous contaminants, which arrive through sewage, atmospheric deposition, agricultural, urban and road runoff, can putting their functioning, water quality and human health at risk. These compounds are present in a large number of consumer goods (pharmaceuticals, personal care products, detergents, pesticides, clothing, electronic material, plastics ...). Its environmental management is complex, as many are not regulated, they are not biodegradable, their potential sinergetic behavior is not known, they circulate through all compartments of ecosystems and may undergo transformation into different more or less toxic compounds. Since this type of contamination has no immediate visible effects, it is only detected when monitoring their presence. Besides, despite the existence of promising technologies in the removal of these contaminants, there is no one that eliminates them universally. In the hypothesis of accumulation of one or more of these substances in the natural environment, particularly in water bodies intended for human consumption, society would face a problem of utmost urgency and for which there is no solution nowadays. The environmental panorama resulting from the occurrence of these contaminants in aquatic systems will be addressed. Concomitantly, we discuss how citizens can contribute to the reduction of pollutants in the environment. info:eu-repo/semantics/publishedVersion