The electrochemical reduction of CO2 in zero-gap alkaline electrolyzers offers a promising route for the sustainable production of value-added chemicals such as ethylene. However, performance is strongly constrained by the interplay between multiphase transport, reaction kinetics, and carbonate chemistry within the membrane electrode assembly (MEA). In this work, a one-dimensional, steady-state, two-phase, non-isothermal multiphysics model is developed to investigate the impact of cathode and membrane transport properties on electrolyzer performance. The model accounts for coupled gas–liquid transport, ionic and electronic conduction, heat transfer, electrochemical reactions, and homogeneous carbonate equilibria. A comprehensive parametric analysis evaluates the effects of catalyst layer thickness, permeability, wettability, electrochemically active surface area, membrane ionic conductivity and thickness, and charge-transfer resistance on current density, CO2 utilization, and ethylene selectivity. The results reveal that performance is governed by trade-offs between gas transport, liquid water distribution, and ionic conduction, with cathode flooding identified as a key limiting factor. By projecting the parameter space onto capillary resistance and catalyst layer hydrophilicity, the results collapse into well-defined trends that enable the identification of optimal design conditions. Specifically, low capillary resistance and hydrophobic catalyst layers mitigate flooding while preserving ionomer hydration, whereas minimizing ionic resistance and maintaining charge-transfer resistance within an optimal range balance activity and selectivity toward C2+ products. These findings provide model-derived design guidelines for improving performance and carbon efficiency in zero-gap alkaline CO2 electrolyzers within the range of conditions investigated.

This study delivers an in-depth exploration of how Computational Fluid Dynamics (CFD) can be employed to examine fluid behavior within unconventional electrochemical reactor geometries. The arrangement of flow paths is fundamental for achieving uniform reactant distribution, avoiding stagnant regions, and reducing concentration gradients that compromise process performance. To improve mass transfer, several design approaches were assessed, including the integration of turbulence-inducing elements and microchannel configurations aimed at promoting mixing and enhancing contact between reactants and electrode surfaces. These concepts were initially tested through CFD simulations and later confirmed through experimental trials. By refining these non-standard geometries, the research offers valuable guidance for developing more efficient and scalable photo/electrochemical panel systems. The most promising configurations were manufactured using 3D printing and subjected to varying operational conditions to quantify their influence on mass transfer. Additionally, phenol degradation tests were performed under controlled flow regimes to validate the computational predictions. Findings demonstrate that optimized flow arrangements substantially improve mass transfer, with the best-performing setup—a dual vertical flow distributor operating at 60 mL·min⁻¹—achieving a 302% increase in mass transfer and a 322% boost in phenol degradation compared to the reference design. These results underscore the effectiveness of the proposed optimization strategy and its potential for future reactor scale-up.

Treating wastewater in high-Andean regions is difficult because low temperatures slow biological processes, yet these areas also receive intense solar radiation. This study tested a continuous-flow raceway reactor as a tertiary treatment in an activated-sludge plant in Marcará, Carhuaz province, Ancash, Peru (3,050 m a.s.l.). For six months, researchers monitored physicochemical and microbiological parameters in real field conditions. Results showed E. coli inactivation above 3.3 Log Units (LRV), strongly linked to direct solar radiation (ρ = 0.85), which confirms that solar disinfection works at high altitudes. Nutrient analysis showed only small variations in nitrogen and phosphorus species between inlet and outlet, indicating that the raceway essentially conserves nutrient levels while acting as a solar disinfection unit. Overall, the raceway system was effective for disinfection, producing effluent suitable for agricultural reuse.

Photochemical modeling was used to evaluate the photodegradation kinetics of sulfamethoxazole (SMX) in sunlit natural freshwater environments, utilizing available data on SMX absorption spectrum, direct photolysis quantum yield, and second-order reaction rate constants with photochemically produced reactive intermediates (PPRIs). The anionic form of SMX is considered here, which prevails in the majority of surface-water conditions (pH > 5.6). SMX would be photodegraded quite rapidly in well-mixed waters under sunny weather, with direct photolysis serving as the predominant pathway in most cases. Among the water parameters, depth and the dissolved organic carbon (DOC) primarily influence the photodegradation of SMX, which would be faster in shallow waters with low DOC. This feature enabled the extension of SMX photochemical lifetime prediction to lakes located within the 60°S-60°N latitude belt, where data on DOC, water depth and sunlight irradiance are available. The fastest photodegradation of SMX (annual average) is expected in the tropical belt, where the combination of high irradiance and low DOC would be most favorable for direct photolysis. With fair weather and good water mixing, typical SMX lifetimes would range from days to some weeks depending on the specific conditions. The lifetimes predicted in shallow waters are consistent with several literature reports of SMX photodegradation kinetics in the laboratory.

Electrochemical conversion of carbon dioxide to ethylene in zero‑gap membrane electrode assembly electrolyzers is a promising route for decarbonizing chemical manufacturing, yet device performance remains limited by the intertwined effects of water transport, carbonate chemistry, ionic conduction, and gas accessibility. This work develops a one‑dimensional, two‑phase, non‑isothermal multiphysics model that integrates detailed multicomponent transport with full carbonate chemistry and multi‑product reaction kinetics, enabling mechanistic interpretation of operating‑condition sensitivity across the practical design space. The model is validated against representative experimental data in polarization behavior, voltage‑loss distribution, product selectivity, and the balance between carbon dioxide reduction and parasitic reactions. Comprehensive contour maps reveal that high ethylene selectivity emerges only within narrow stability windows constrained by water management and carbonation. A higher temperature accelerates charge-transfer kinetics and reduces ohmic losses but strengthens hydrogen evolution, while increasing pressure improves carbon dioxide supply but eventually triggers a catalytic shift toward formate and rapid hydroxide depletion through carbonation. Similarly, optimum operation in the humidity–water drag domain requires full but not excessive cathode hydration. Insufficient hydration collapses ionic conductivity and increases hydrogen evolution, whereas over‑hydration floods the cathode, blocks gas access, and promotes carbonation. Across all dimensions, performance is maximized only when hydration, ionic transport, carbon dioxide solubility, and carbonate chemistry are simultaneously balanced. These mechanistic insights yield quantitative design rules directly applicable to stack control strategies and material selection, advancing carbon dioxide‑to‑ethylene electrolysis toward durable, industrially relevant operation.

Phosphorus is a non-renewable resource essential for agriculture, yet its excessive discharge from wastewater contributes to eutrophication. Advanced Oxidation Processes (AOPs), such as H2O2/UV, can convert non-bioavailable non-reactive phosphorus (NRP) into bioavailable reactive phosphorus (RP), facilitating its recovery for potential reuse, such as in agricultural irrigation. However, complex reaction kinetics and organic matter (OM) challenge photo-oxidation reactor design. This study develops and validates a lumped kinetic model framework to describe the photo-oxidative conversion of dissolved organic phosphorus (DOP) and acid-hydrolyzable phosphorus (AHP) to RP. The methodology integrates experiments in a lab-scale photoreactor using phytic acid (PA) and sodium hexametaphosphate (HMP) as model compounds for DOP and AHP, respectively, with and without OM. Statistical tools, including Bland-Altman analysis and weighted least-squares with covariance diagonalization, elucidated reaction pathways and reduced parameter correlation. Mass balance analysis confirmed HMP inertness under the tested conditions. Topology selection revealed that a simple direct conversion model (DOP -> RP) was insufficient, whereas a sequential model including an AHP intermediate (DOP -> AHP -> RP) provided the minimal structural complexity to satisfy the global chi-squared goodness-of-fit test. The model framework enables the quantification of the inhibitory role of OM (radical scavenging and UV-screening) yielding a reduced apparent H2O2 photolysis rate. The calibrated framework reproduces the RP profile with high accuracy (R-2 >0.92) and can be used, given initial concentrations and operating setpoints, to estimate oxidant doses and irradiation times for end-of-pipe UV/H2O2 systems converting NRP to RP for potential recovery. A key limitation is that kinetic parameters are matrix-dependent; therefore, the framework must be recalibrated for each target wastewater. Once recalibrated, the model provides a statistically grounded tool for designing and optimizing H2O2/UV treatment of recalcitrant phosphorus.

The worrying energy and climate situations make it necessary to face a transition to a carbon-neutral economy. In this context, green hydrogen plays a crucial role in the future energy landscape. Besides other technologies, thermochemical water splitting represents a promising route for renewable hydrogen generation, using thermosolar energy as the primary energy source. In this study, different types of perovskites La0.8Me0.2NiO3 +/-delta (Me = Al, Ba and Ca) were synthesised via reactive grinding. Their redox performance was evaluated under different thermal reduction temperatures (1200-800 degrees C), obtaining materials with hydrogen production values ranging from 4.51 to 5.31 cm3STP/gactive material & sdot;cycle when the reduction was performed at 800 degrees C, exceeding those already reported values for similar materials at higher temperatures. In order to obtain suitable configurations for their implementation in solar reactors, powdered perovskites were shaped into macrostructures such as pellets, reticulated porous ceramic (RPC) structures and thin films deposited over ceramic monoliths. Compared to powdered materials, the macrostructures exhibited higher hydrogen production attributed to enhanced gas-solid contact and more efficient heat transfer within the structures. The best performance was obtained by La0.8Ca0.2NiO3 +/-delta supported as a thin layer over the ceramic monolithic structure, with productions up to 14.91-16.33 cm3STP/gactive material & sdot;cycle using thermal reduction temperatures of 800 and 1000 degrees C, respectively. These results confirm that shaping strategies enhance the already remarkable redox activity of perovskites and enable their integration into volumetric solar reactors. This represents a significant step forward in the development of scalable green hydrogen production systems based on renewable solar thermal energy.

This work presents a comprehensive study on the application of Computational Fluid Dynamics (CFD) to analyze flow patterns in different unconventional electrochemical geometries. Flow configuration plays a critical role in ensuring uniform reactant distribution, preventing stagnant zones, and minimizing concentration gradients that could reduce process efficiency. Various strategies were investigated to optimize mass transfer, including turbulence promoters and microchannel designs that enhance mixing and increase reactant interaction with the electrode surface. These optimizations were first evaluated through CFD simulations and subsequently validated experimentally. By optimizing these unconventional geometries, this study provides insights into how future panel-based photo/electrochemical systems can be more efficient and scalable. The most effective designs were fabricated using 3D printing and tested under different operational conditions to measure their impact on mass transfer performance. Finally, phenol degradation experiments were conducted under controlled flow conditions to validate the numerical models. The results confirm that optimized flow configurations significantly enhance mass transfer, and phenol degradation with the most optimized configuration (double vertical flow distributor at 60 mL min-1) achieving a 302 % increase in mass transfer compared to the baseline and a 322 % increase in phenol degradation rate. This supports the efficacy of the methodology for reactor optimization and potential scale-up applications.

A one-dimensional, two-phase, non-isothermal multiphysics model of a zero-gap alkaline CO2 electrolyzer is developed and validated to capture coupled transport, carbonate chemistry, and reaction kinetics. High ethylene selectivity is confined to a narrow operating window controlled by water management, CO2 availability, and ionic transport. Cathode hydration is identified as a key governing factor. Insufficient hydration limits ionic conductivity and promotes hydrogen evolution, whereas over-hydration induces flooding, restricts gas transport, and accelerates carbonation. Increasing temperature enhances kinetics but shifts selectivity toward hydrogen, while increasing pressure improves CO2 supply but favors formate formation via hydroxide depletion. These results establish that optimal performance requires a precise balance between hydration, gas transport, and carbonate chemistry, providing quantitative guidance for operation and control.

Micro-and nano-plastics (MNPs) have raised concerns regarding their potential ecological and human health impacts. Although these contaminants are not yet regulated under environmental legislation, international and European institutions are beginning to adopt directives to prevent their release through wastewater effluents. However, most existing treatment technologies are ineffective at removing MNPs. In this context, this study explores, for the first time, the use of anodic oxidation (AO) using an electrochemical flow-through cell equipped with commercial electrodes for the removal of polyethylene (PE) MNPs from water. Although limited removal was achieved (50 f 5% at 15 mA cm-2), the primary benefit of the AO process was the physical agglomeration of the PE MNPs, which enhanced the efficiency of subsequent filtration using either a 5 & micro;m cellulose acetate membrane (from 73 f 2% to 85 f 3% at 15 mA cm-2) or a 20 & micro;m stainless steel grid (from 51 f 2% to 78 f 5% at 15 mA cm-2). A comprehensive characterisation of the PE agglomerates revealed that the AO process induced physicochemical changes at their surface. Although the molecular weight remained practically unchanged, the study of the GPC-IR measurements showed that chain scission may have occurred due to an increase in short-chain branches. The & micro;-FTIR spectra of the treated PE MNPs showed vibrational bands associated with oxygen-containing functional groups, potentially introduced during the AO process. Furthermore, NMR analysis revealed that oxidation products were confined to the surface of the PE MNPs.

Aquaponics enables the simultaneous production of fish and crops, while reclaimed urban wastewater is increasingly considered for agricultural reuse due to water scarcity. However, its application in aquaponic systems remains largely unregulated. This study evaluates (i) the effectiveness of an advanced tertiary wastewater treatment in producing water suitable for aquaponics and (ii) the impact of reclaimed wastewater on plant and fish yields. Therefore, this study lays the groundwork for a potential shift in legislation regarding water reuse practices.,Wastewater treatment plant effluent was subjected to a tertiary treatment consisting of ultrafiltration (UF), electrooxidation (EO), and UVC-LED irradiation. The treated water was used in a small-scale recirculating aquaponic system stocked with Nile tilapia (Oreochromis niloticus) and lettuce (Lactuca sativa), while a parallel system using dechlorinated tap water served as the control. Physicochemical and microbiological parameters were analyzed in water, fish, and plants.,Higher concentrations of nutrients such as total phosphorus and nitrates in reclaimed wastewater contributed to increased crop yields. Regarding microbial indicators no pathogenic microorganisms were detected. No accumulation of microplastics, PFAS nor pharmaceuticals was observed during system operation. Detected PFAS concentrations remained well below regulatory limits for drinking water. Ecotoxicological assays showed no inhibitory effects in either water source, and in some cases, a stimulating response associated with the higher nutrient load of the reclaimed wastewater. Tilapia growth was comparable between cycles, with FCR values around 0.7, indicating high feed efficiency.,Overall, reclaimed wastewater subjected to adequate tertiary treatment represents a safe and effective alternative for aquaponic production.

Due to water shortages, the Sahrawi refugee communities located in Tindouf (Algeria) suffer structural nutritional deficiencies derived from their diet based mainly on carbohydrates (rice, cereals, sugar) supplied by the World Food Bank due to the logistical difficulties of transport to the Sahara Desert. The SAHARAPONICS project has made it possible to develop systems for the local production of high-quality protein foods (fish) and vegetables rich in vitamins and minerals that can reduce the incidence of anaemia in fertile women in the communities and indicators of propensity to diabetes in the general population. To this end, a low water consumption aquaponic system has been designed based on locally available materials. The project has included the development of assembly and operation documentation in the local language and the training of responsible personnel to ensure the replicability and long-term use of the systems. Although the implementation generates significant changes in the daily lives of the inhabitants, increasing their workload, the long-term benefits, in terms of food security, economic development, and empowerment, outweigh the initial challenges. Beyond the expected impact on the improved use of water, provision of food and improvement of health, the technology also generated economic opportunities for vulnerable communities in a sustainable way. The users' feedback pointed out optimistic evidence and insights into the potential long-term impacts of the technology, supporting aquaponics as a successful concept that shows the community the possibility of producing high-nutritional-value food with very low water consumption using innovative systems based on locally available materials.

The development of antiviral coatings is crucial for mitigating pathogen transmission. This study evaluates the influence of fabrication methods on the structural, optical, and antiviral properties of nanostructured (NSs) ZnO thin-film coatings for MS2 bacteriophage inactivation under ambient white light (similar to 1000 lux). The quality and morphology of ZnO nanostructures prepared via solution-based methods (sol-gel and hydrothermal) and aerosolassisted chemical vapour deposition (AACVD) were compared. Structural and optical analyses revealed that AACVD produced highly crystalline, homogeneous ZnO film coatings with well-oriented [001] growth, while solution-based methods resulted in partial amorphous characteristics and bandgap blue shift due to carbon contamination. Antiviral tests showed that AACVD ZnO film coatings achieved a 4-log reduction (99.99 %) in MS2 infectivity within 2 h, outperforming the 2-log reduction achieved by solution-based coatings. These results underscore AACVD as a scalable and efficient method for fabricating high-performance ZnO-based antiviral coatings.

The production of green hydrogen is one of the main targets of current energy and environmental policies. In this context, thermochemical water splitting is one of the potential methodologies that enable its production. This process is based on the thermal reduction of a metal oxide, followed by its re-oxidation with water releasing hydrogen. The main problem of this process, which hinders its full-scale application, is that reducing the metal oxide usually requires very high temperatures (>1500 degrees C). To decrease this reduction temperature, non-stoichiometric oxides such as perovskites have been proposed. In a previous work, the authors have presented La1-xSrxMeO3 +/-delta (x = 0.2-0.4; Me = Mn, Fe and Co) perovskites as active materials decreasing the operation temperature to 1400 degrees C. However, those perovskites showed a significant lack of stability upon cycling, limiting their use in a future scale-up of the process. In this work, we present a multi-substituted perovskite type A(1-x)A'xB1-yB'O-y(3 +/-delta) (La0.6Sr0.4Co0.2Fe0.8O3 +/-delta, named LSCF) as redox material with increasing stability and remarkable activity in the hydrogen production cycles even at temperatures below 1000 degrees C. This material was synthesised by reactive grinding as a green synthesis method optimising the variables of the process. Three reduction temperatures for the thermochemical water splitting were evaluated in the range 800-1200 degrees C at the same oxidation temperature of 800 degrees C. LSCF perovskite has been used in powder form with a H-2 production of 5.22 cm(3)STP/g(material)cycle when the reduction was performed at 800 degrees C and 6.83 cm(3)STP/g(material)cycle when this reduction step was performed at 1000 degrees C. Afterwards, the LSCF was shaped into two different macroporous structures looking for a potential scaling-up of the process: reticulated porous ceramic structure (RPC) and a ceramic monolith structure with straight and well-ordered channels in which the perovskite forms a thin layer over the internal channels surface. The macroscopic structures exhibited good activity and stability working isothermally at 800 degrees C under N-2 atmosphere, reaching H-2 productions higher than 10 cm(3)STP/g(material)cycle. Particularly, the monolithic structure, characterised by its open macroporosity improves the heat transfer phenomena and the contact between the gas-phase and the perovskite, obtaining a stable hydrogen production under isothermal conditions of 17 cm(3)STP/g(material)cycle at 800 degrees C. That could be increased up to 32.5 cm(3)STP/g(material)cycle when the reduction step of the thermochemical water splitting is performed at 1000 degrees C. To the best of our knowledge, this is the higher value obtained for hydrogen production by a perovskite in this application at this reaction conditions. These results confirm the LSCF as a potential material for green hydrogen production by low-temperature thermochemical cycles.

Photochemical mineralisation is an abiotic process by which the organic matter in natural waters, which is mostly dissolved, is eventually transformed into CO2 by the action of sunlight. The process has important implications for global C cycling, the penetration of sunlight into the water column, photochemical reactions, and microbial processes. Here we applied an approximated photochemical model to assess the extent of CO2 photogeneration by mineralisation of dissolved organic matter in lakes located between 60°S and 60°N latitude. The results suggest that, although lake-water organic matter would usually undergo faster photomineralisation in the tropical belt than elsewhere, by far the highest contributions to the photochemical production of CO2 would come from lakes located between 30°N and 60°N latitude. In particular, of the ~7 × 104 lakes we selected for the study, around 50 % of CO2 photogeneration would be accounted for by just 7 large lakes, of which only one is located in the tropical belt. It appears that the lake surface is a very important factor that affects the overall photomineralisation potential of dissolved organic matter.

The equivalent monochromatic wavelength (EMW) approximation allowed us to predict the photochemical lifetimes of the lipid regulator metabolite clofibric acid (CLO, triplet sensitization) and of the non-steroidal antiinflammatory drug diclofenac (DIC, direct photolysis & thorn; triplet sensitization) in lakes worldwide. To do so, we used large lake databases that collect photochemically significant parameters such as water depth and dissolved organic carbon, which allow for a preliminary assessment of some photoreactions. Extension to other photoreactions is currently prevented by the lack of important parameters such as water absorption spectrum, suspended solids, nitrate, nitrite, pH, and inorganic carbon on a global scale. It appears that triplet-sensitized CLO photodegradation would be strongly affected by the dissolved organic carbon values of the lake water and, for this reason, it would be fastest in Nordic environments. By contrast, direct photolysis (DIC) would be highly affected by sunlight irradiance and would proceed at the highest rates in the tropical belt. Interestingly, the predicted lifetimes of CLO and DIC are shorter than the residence time of water in the majority of global lake basins, which suggests a high potential for photoreactions to attenuate the two contaminants on a global scale. Photodegradation of DIC and CLO would also be important in waste stabilization ponds, except for elevated latitudes during winter, which makes these basins potentially cost-effective systems for the partial removal of these emerging contaminants from wastewater.

Solar water disinfection (SODIS) is a low-cost but effective process for obtaining safe drinking water at the household level in resource-poor environments. SODIS is a solar energy-driven method where inactivation of microorganisms occurs due to the effect of incident UV photons and/or increased water temperature. Consequently, the optical and mechanical properties of SODIS container materials play a critical role. Previously, we reported advanced weathering studies of 10 L polypropylene (PP) transparent jerrycans (TJCs) without UV stabiliser, which became extremely fragile after only 2 months of solar exposure, leading to a complete loss of structural integrity. Herein, we evaluate food-safe 10 L PP SODIS TJCs which have been enhanced with UV-stabiliser. We report that although TJCs with UV-stabiliser are durable and capable of achieving bacterial inactivation of > 4 Log Reduction Values for Escherichia coli, it does not sufficiently inactivate the protozoan pathogen Cryptosporidium parvum. UV-stabilized TJCs had lower disinfection rates despite having increased durability compared to previous TJC prototypes. We attribute this loss of microbicidal efficacy to poorer UV transmission caused by the addition of the UV-stabiliser. In addition, cytotoxicity studies of UV-stabilised PP TJCs revealed several cell viabilities dropping below 80 %, indicating they were slightly cytotoxic, as per ISO-10993-5:2009. We conclude that, despite early indications, PP is ultimately not a suitable container material for long-term SODIS applications.

Solar-driven thermochemical water splitting has the potential to transform concentrated solar energy into green hydrogen and other solar fuels. In this work, La0.8Ca0.2MeO3 +/-$ (Me = Co, Ni, Fe and Cu) perovskites have been synthesised by a modified Pechini method and evaluated as materials for hydrogen production by two step thermochemical water splitting cycles. Performing the thermal reduction at temperatures of 1200 and 1000 degrees C, while the oxidation is done at 800 degrees C, allows a remarkable and stable hydrogen production after 5 consecutive cycles. However, the perovskites suffer changes in the structure after each redox cycle, with potential effects in the long-term cyclic operation. On the contrary, the isothermal thermochemical cycles at 800 degrees C produce a stable amount of hydrogen with each consecutive cycle maintaining the perovskite structure. This hydrogen production ranges from 3.60 cm3 STP/gmaterial$cycle for the material with the lowest productivity (La0.8Ca0.2FeO3 +/- d) to 5.02 cm3 STP/gmaterial$cycle for the one with the highest activity (La0.8Ca0.2NiO3 +/- d). Particularly the Ni-based material shows the highest H2 productivity accompanied by very good material stability after 15 consecutive cycles, being possible to combine with current solar thermal facilities based on concentrated solar power technologies like plants with central receivers.(c) 2023 The Author(s). Published by Elsevier Ltd on behalf of Hydrogen Energy Publications LLC. This is an open access article under the CC BY-NC-ND license (http:// creativecommons.org/licenses/by-nc-nd/4.0/).

Solar-driven thermochemical water splitting has the potential to transform concentrated solar energy into green hydrogen and other solar fuels. In this work, La0.8Ca0.2MeO3±δ (Me = Co, Ni, Fe and Cu) perovskites have been synthesised by a modified Pechini method and evaluated as materials for hydrogen production by two step thermochemical water splitting cycles. Performing the thermal reduction at temperatures of 1200 and 1000 °C, while the oxidation is done at 800 °C, allows a remarkable and stable hydrogen production after 5 consecutive cycles. However, the perovskites suffer changes in the structure after each redox cycle, with potential effects in the long-term cyclic operation. On the contrary, the isothermal thermochemical cycles at 800 °C produce a stable amount of hydrogen with each consecutive cycle maintaining the perovskite structure. This hydrogen production ranges from 3.60 cm3 STP/gmaterial·cycle for the material with the lowest productivity (La0.8Ca0.2FeO3±δ) to 5.02 cm3 STP/gmaterial·cycle for the one with the highest activity (La0.8Ca0.2NiO3±δ). Particularly the Ni-based material shows the highest H2 productivity accompanied by very good material stability after 15 consecutive cycles, being possible to combine with current solar thermal facilities based on concentrated solar power technologies like plants with central receivers.

This study is the first environmental comparison between a UV-C LED lamp (emitting at 265 nm) and mercury lamps employed in a lab-scale photoreactor for water treatment purification purposes, using the removal of diclofenac as a case study. Ex-ante life cycle assessment (LCA) methodology was used as a robust method to identify hotspots and recommendations at the early stage of the UV-C LEDs technology. The functional unit was defined as "the treatment of 1 L of polluted water with 20 mg L-1 of diclofenac to achieve a 90% removal of the contaminant", while the system boundaries include the production and the operation of the photoreactors, following a cradle-to-gate approach. Several scenarios were explored, and overall, the UV-C LED lamp shows a promising environmental performance, with less or similar potential impacts than the mercury lamps in the 16 categories selected from the Environmental Footprint (EF) method. In particular, it reveals less impact in "human toxicity non-cancer" and "resource use minerals and metals" and presents electricity as the main source of impact. Given the higher efficacy of the UV-driven advanced oxidation processes compared to the UV irradiation alone, and since no studies have previously been conducted on the sustainability of free chlorine (FC) as an oxidant in water treatment, a comparison between UV-C, UV-C/H2O2, and UV-C/FC while employing the 265 nm UV-C LED lamp was also assessed. UV-C/H2O2 was more sustainable than UV-C/FC for the same treatment time, but both led to an overall impact reduction of 35% and 30%, respectively. To increase sustainability, employing cleaner energy sources such as photovoltaic or wind energy also resulted in an 80% and 93% reduction in the "climate change" category. Overall, this study demonstrates that using UV-C LEDs and the selected oxidants for water purification is beneficial and encourages the scale-up of the system.