63 research outputs found
Super absorbent polymers for future agriculture: a circular approach for soil fertilization and irrigation
No full textIn recent decades, agricultural productivity has exponentially increased thanks to the widespread adoption of intensive practices promoted by the green revolution. This progress, however, has come at a significant environmental cost. To sustain food production for a rapidly growing global population, fertilizers use has escalated dramatically, surpassing 55 million tons annually [1]. This trend is expected to continue, with projections indicating exponential increases in fertilizers demand, raising serious concerns regarding long-term sustainability, resource depletion, and environment degradation. In this framework, excessive and uncontrolled fertilizers application has led to numerous ecological issues, including soil depletion, water pollution, eutrophication of aquatic ecosystems, and contributions to climate change [2]. At the same time, the growing global water crisis is demonstrating the importance of using water more efficiently in agriculture. To afford these problems, superabsorbent polymers (SAPs), particularly potassium-based polyacrylates (SAP-K), have emerged as promising materials due to their ability to retain significant quantities of water, improve soil moisture [3]. These materials are low-cost, non-toxic, non-polluting, and do not contribute to soil salinization, making them suitable for sustainable agricultural applications [3].
In this work we explore an innovative use of SAPs-K with the dual purpose of: 1) enriching them with nutrients to act as slow-release fertilizers; 2) recovering steam from high-temperature emissions, such as industrial chimneys.
To our knowledge, although SAPs-K have been marketed for many years, no studies have yet addressed these combined functionalities.
In the present study, commercial SAPs-K were modified with nutrient-rich precursors—such as starch, ethylenediamine, L-asparagine, and hydroxyapatite—to introduce essential elements, like nitrogen, calcium, and phosphorus. The modified materials were tested for their water vapor absorption capacity at 160 °C, and the most promising formulations were further evaluated for nutrient release in soil.
The results demonstrated that nutrients enrichment significantly enhanced the water vapor absorption capacity of the polymers (Figure 1a). To validate their potential application in agriculture, nutrients release tests were conducted, showing that the modified materials improved soil water retention up to 40% and enabled the gradual release of nutrients into the soil (Figure 1b).
These findings demonstrate the potential of nutrient-enriched SAPs-K as dual-function materials for sustainable agriculture. By combining water vapor recovery with controlled nutrients and water release, the developed systems offer a promising solution to address water scarcity and fertilizer inefficiency. Their low cost, environmental compatibility, and circular approach make them valid candidates for future agricultural innovation.
References
1. F. Zapata, Introduction to nitrogen management in agricultural systems, in Guidelines on Nitrogen Management in Agricultural Systems, International Atomic Energy Agency, Training Course Series, No. 29, 2008, Vienna, Austria
2. J. Liu, Y. Su, Q. Li, Q. Yue, B. Gao, Preparation of wheat straw based superabsorbent resins and their applications as adsorbents for ammonium and phosphate removal, Bioresour. Technol. 2013, 143, 32–39. https://doi.org/10.1016/j.biortech.2013.05.100
3. Behera, S., & Mahanwar, P. A. Superabsorbent polymers in agriculture and other applications: a review. Polymer-Plastics Technology and Materials, 2019, 59(4), 341–356. https://doi.org/10.1080/25740881.2019.164723
Floating Photocatalysts as a Sustainable Solution for Water Harvesting in Vulnerable Communities
No full textThe exponential growth of the global population, projected to exceed 9 billion people by 2050, combined with increasing water scarcity driven by climate change, is placing unprecedented pressure on the world's water resources [1]. This issue is even more pronounced in developing countries, where water scarcity is a key factor behind numerous public health crises, during which unsanitary conditions expose both patients and doctors to risks of disease transmission [2].
In this challenging scenario, treating the tons of wastewater generated every day offers a promising solution. By transforming wastewater into a viable alternative water source, this approach addresses both resource scarcity and environmental sustainability. Although various technologies have been developed for water depollution (e.g., filtration, chemical or biological treatments) [3], they generally fail to remove contaminants of emerging concern (CECs) due to their high chemical stability, so developing efficient technologies for wastewater purification is crucial to mitigating water scarcity and ensuring access to safe water for all. In this framework, photocatalysis plays a pivotal role; indeed, the use of sunlight, an extremely powerful and abundant energy source, represents a vital resource in light of the current energy crisis. However, developing photocatalytic materials capable of exploiting the entire solar spectrum for pollutant photodegradation is challenging. Additionally, the most advanced materials reported in the literature are typically used as dispersed powders. Even if working with fine powders offers several benefits (e.g., high dispersion and impressive photoactivity), it also presents critical challenges, such as the difficulty of recovering them from the reaction mixture, which leads to contamination issues and additional costs [4]. For this reason, immobilizing photocatalysts strikes a balance between their advantages and the need for practical application by enhancing stability and enabling easier handling. In this context, floating photocatalysts offer the advantage of maximizing both light utilization and surface aeration, as they can remain at the air-water interface. Their use also reduces post-treatment costs. These foundations inspired the development of the project “Water Decontamination by Sunlight-Driven Floating Photocatalytic Systems” (SUNFLOAT). Within the SUNFLOAT project, various safe, cost-effective, and highly efficient photocatalysts designed to operate under solar irradiation were successfully fabricated and immobilized on different synthetic and natural floating supports [5-6]. The resulting materials were rigorously tested for the photodegradation of various CECs under both simulated and real sunlight conditions. The innovation introduced by the SUNFLOAT project highlights the practical viability of floating photocatalysts under natural solar conditions. The project underscores the effectiveness of these novel materials in harnessing solar energy for sustainable water purification. By proving their functionality under real sunlight, this initiative represents a significant advancement, offering an eco-friendly and scalable solution to improve water quality for remote communities facing water scarcity.
References:
[1]: He, C., Liu, Z., Wu, J., Pan, X., Fang, Z., Li, J., Brett, A.B., Nat. Commun.12, 4667 (2021).
[2]: https://www.cdc.gov
[3] Galloni, M.G., Ferrara, E., Falletta, E., Bianchi, C.L., Catalyst 12(8), 923, (2022).
[4] Djellabi, R., Giannantonio, R., Falletta, E., Bianchi, C.L., Curr. Opin. Chem. Eng.33, 100696 (2021).
[5] Galloni, M.G., Falletta, E., Mahdi, M., Giordana, A., Cerrato, G., Boffito, D.C., Bianchi, C.L., Adv. Sus. Syst. 2300565 (2024).
[6] Galloni, M.G., Nikonova, V., Cerrato, G., Giordana, A., Pleva, P., Humpolicek, P., Falletta, E., Bianchi, C.L., J. Environ. Man., 369, 122365, (2024)
Hydrogen production from wastewater via Pt-free cathodes: a sustainable paradigm towards carbon-neutral energy
No full textIntroduction
In modern times, shifting towards carbon-neutral energy production is crucial for tackling climate change and ensuring a reliable energy supply for future generations. Hydrogen (H2) stands out as a promising energy carrier due to its high energy density and versatility, and its market is projected to expand rapidly. However, actually, only about 4% of produced hydrogen comes from renewable sources such as electrochemical water splitting [1]. This limitation is mainly due to the high overpotential needed for the Oxygen Evolution Reaction (OER), which hampers the efficiency of hydrogen generation, along with the prevalent use of noble metal-based electrodes that are expensive limiting their use. To address this issue, wastewater, typically characterized by high levels of COD (Chemical Oxygen Demand), can act as an effective electron donor during the anodic reaction, significantly lowering the oxidation potential compared to traditional OER methods. In this scenario, process intensification can offer a crucial contribution to overcome these challenges, aligning with the United Nations’ 2030 Agenda for Sustainable Development. By focusing on key objectives, such as clean water and sanitation (Goal 6) and affordable and clean energy (Goal 7), the electrochemical hydrogen production from wastewater, showcases its potential to integrate energy generation with environmental remediation [2]. Building on these concepts, this research explores the use of a noble metal-free cathode made from an electrodeposited composite of cobalt phosphide (CoP) and elemental phosphorus (P) for hydrogen generation from wastewater. This approach exemplifies process intensification by enabling efficient hydrogen production from simulated wastewater, thereby contributing to a sustainable circular economy while promoting advancements in clean energy technologies.
Methods
The CoP/P electrode was fabricated according to Falletta and Bernasconi et al. [3] and the synthetic process is schematized in Figure 1A.
Electrochemical experiments were conducted in a 100 mL single-chamber cell featuring a three-electrode setup using a Pt foil anode, a CoP/P cathode, and a Standard Calomel Electrode (SCE) as the reference. A 60 mL solution of Rhodamine B (5 mg/L) was used as simulated wastewater, adding 0.5 M NaOH or H2SO4 as the supporting electrolyte. To ensure inert environment, nitrogen was bubbled into the cell prior to starting the experiments. The reactions were performed for 2 hours at a constant potential. The Rhodamine B degradation was evaluated using UV-vis spectroscopy selecting the wavelength at 554 nm, while hydrogen production was assessed at the midpoint and conclusion of the test by collecting gas samples for analysis with a GC equipped with aTCD detector.
Results and discussion
The morphology of the investigated electrode was evaluated through Scanning electron microscopy (SEM) revealing that CoP matrix alone (Figure 1B, CoP/P) is characterized by low-roughness, wherease the addition of red phosphorus particles drastically alters the material's morphology. The presence of P microparticles was further confirmed by the EDS elemental mapping of Co and P. Additionally, XRD analysis (data not shown) revealed that the deposited material, i.e., CoP/P, appears to be amorphous wherease, after annealing the level of crystallinity increases.
The tests of hydrogen generation and RhB electrooxidation were performed at a fixed cathodic potential. Preliminary, electrochemical investigation were carried out through Linear Sweep Voltammetry (LSV) in the cathodic region. These studies helped determining the optimal working potential for efficient hydrogen generation showing that in acidic conditions (0.5 M H2SO4) a cathodic potential of -1 V vs SCE was sufficient to produce sufficient current, while in an alkaline environment (0.5 M NaOH) a more negative potential (-2 V vs SCE) was required due to the lower mobility of OH− ions. Based on these findings, the electrochemical treatment of the simulated wastewater was carried out at the potentials identified. Figure 1C highlights RhB electrochemical degradation in both acidic and alkaline environments, revealing a higher RhB removal efficiency in the alkaline setting likely due to the higher anodic potential observed in alkaline conditions (+1.9 V compared to +1.6 V in acid), which promotes indirect RhB oxidation via the generation of transient radicals. Additionally, hydrogen generation (Figure 1D) tests indicated that a greater hydrogen yield was achieved in the alkaline environment, compared to the acidic conditions. Further tests are underway in quasi-real conditions to investigate the impact of competing species on both processes in more complex water matrices.
Conclusions
In the present work it was demonstrated that in the wiev of process intensification, the electrochemical treatment of wastewater using Pt-free electrodes offers a promising and sustainable approach for achieving both clean water recovery and hydrogen production, contributing to a greener and more resource-efficient future
Floating photocatalysts as key players in reshaping sustainable wastewater treatment: a green transition towards future society
No full textClimate change is reshaping water access, causing droughts and floods: there is not enough water, and the available amount is usually tainted with pollutants [1]. So, treating polluted surface water urgently requires fast and efficient solutions. Heterogeneous photocatalysis has emerged to degrade mixtures of pollutants without adding chemical oxidants under mild conditions [2]. However, photocatalytic processes are scarcely effective when used to treat large volumes of contaminated matrices due to large reactor sizes, limited light penetration, high energy costs, and difficulties in recycling/reusing the photocatalysts. To facilitate pollutants degradation, different composites combine high adsorption capacity and photoreactivity [2]. However, they are nano-sized materials that, although common, raise concerns about nanotoxicity. The ideal photocatalyst should be active, selective, stable, sustainable and easy to handle.
At present, floating photocatalysts are interesting alternatives to be exploited, since they maximize light utilization and surface aeration, enhancing pollutants abatement performance and decreasing post-treatment costs [2]. If properly developed to be sustainable and efficient, they could reshape sustainable wastewater treatment for future societies.
Herein, we present our results related to the development of sustainable photoactive materials obtained by immobilizing innovative photocatalysts (i.e., bismuth oxyhalides) on eco-friendly floating supports (alginate spheres, sponges, and Lightweight Expanded Clay Aggregates). Bismuth oxyhalides can concentrate different pollutants (dyes, drugs, polyphenols) on their surface in the dark and quantitatively degrade them after exposure to solar light. A targeted study on the role of the water matrix, catalyst dosage, and recycling tests, approaching actual application, will provide insights into the potentialities and limitations for real-world application, opening the view toward the future use of these innovative systems, and acting as a bridge between environmental protection and sustainability
Driving sustainability: integrating hydrogen production and wastewater treatment via advanced noble metals-free electrodes
No full textCurrently, the transition toward clean energy systems that do not emit carbon dioxide is an urgent task for the creation of a sustainable energy society, in line with Goal 7 of the 2030 Agenda [1]. In this context, hydrogen (H2) emerges as a promising energy storage medium. Unfortunately, approximately 96% of its production relies on non-renewable sources, while only 4% originates from water splitting. In this latter, a considerable electrochemical overpotential is needed to trigger the hydrogen evolution reaction (HER) on the electrode surface. Moreover, highly efficient working electrode requires the use of electrocatalysts to minimize the energy barrier associated with HER. For these reasons, this method is costly [2]. In the last decades, it has been demonstrated that organic pollutants in wastewaters containing high level of chemical energy are excellent electron donor and suitable candidates for H2 production [3]. This promising approach could also help in solving the issues related to the environmental pollution. Based on these premises, this research focuses on the use of a noble metal-free cathode, for efficient hydrogen generation from simulated wastewater through water splitting, with this innovative approach, the double goal of clean energy system and wastewater treatment can be matched
Solar-powered solutions: floating photocatalysts for sustainable water purification in a resource-challenged world
No full textThe exponential growth of the global population, projected to exceed 9 billion people by 2050, combined with increasing water scarcity driven by climate change, is placing unprecedented pressure on the world's water resources [1]. This issue is even more pronounced in developing countries, where water scarcity is a key factor behind numerous public health crises, during which unsanitary conditions expose both patients and doctors to risks of disease transmission [2].
In this challenging scenario, treating the tons of wastewater generated every day offers a promising solution. By transforming wastewater into a viable alternative water source, this approach addresses both resource scarcity and environmental sustainability. Although various technologies have been developed for water depollution (e.g., filtration, chemical or biological treatments) [3], they generally fail to remove contaminants of emerging concern (CECs) due to their high chemical stability, so developing efficient technologies for wastewater purification is crucial to mitigating water scarcity and ensuring access to safe water for all. In this framework, photocatalysis plays a pivotal role; indeed, the use of sunlight, an extremely powerful and abundant energy source, represents a vital resource in light of the current energy crisis. However, developing photocatalytic materials capable of exploiting the entire solar spectrum for pollutant photodegradation is challenging. Additionally, the most advanced materials reported in the literature are typically used as dispersed powders. Even if working with fine powders offers several benefits (e.g., high dispersion and impressive photoactivity), it also presents critical challenges, such as the difficulty of recovering them from the reaction mixture, which leads to contamination issues and additional costs [4]. For this reason, immobilizing photocatalysts strikes a balance between their advantages and the need for practical application by enhancing stability and enabling easier handling. In this context, floating photocatalysts offer the advantage of maximizing both light utilization and surface aeration, as they can remain at the air-water interface. Their use also reduces post-treatment costs. These foundations inspired the development of the project “Water Decontamination by Sunlight-Driven Floating Photocatalytic Systems” (SUNFLOAT). Within the SUNFLOAT project, various safe, cost-effective, and highly efficient photocatalysts designed to operate under solar irradiation were successfully fabricated and immobilized on different synthetic and natural floating supports [5-6]. The resulting materials were rigorously tested for the photodegradation of various CECs under both simulated and real sunlight conditions. The innovation introduced by the SUNFLOAT project highlights the practical viability of floating photocatalysts under natural solar conditions. The project underscores the effectiveness of these novel materials in harnessing solar energy for sustainable water purification. By proving their functionality under real sunlight, this initiative represents a significant advancement, offering an eco-friendly and scalable solution to improve water quality for remote ommunities facing water scarcity.
References:
[1]: He, C., Liu, Z., Wu, J., Pan, X., Fang, Z., Li, J., Brett, A.B., Nat. Commun.12, 4667 (2021).
[2]: https://www.cdc.gov
[3]: Galloni, M.G., Ferrara, E., Falletta, E., Bianchi, C.L., Catalyst 12(8), 923, (2022)
[4]: Djellabi, R., Giannantonio, R., Falletta, E., Bianchi, C.L., Curr. Opin. Chem. Eng.33, 100696 (2021)
[5]: Galloni, M.G., Falletta, E., Mahdi, M., Giordana, A., Cerrato, G., Boffito, D.C., Bianchi, C.L., Adv. Sus. Syst. 2300565 (2024),
[6] Galloni, M.G., Nikonova, V., Cerrato, G., Giordana, A., Pleva, P., Humpolicek, P., Falletta, E., Bianchi, C.L., J. Environ. Man., 369, 122365, (2024
The Role of Bismuth in Developing Bio-Based Materials for Efficient Polyphenol Adsorption and Solar Photodegradation
No full textOlive oil production is one of Europe's best-performing agricultural sectors. It produces olive oil and undesirable by-products (wastes), such as olive mill wastewater (OMWW) and organic waste. OMWW contains large amounts of organic compounds (primarily polyphenols, phenols, and tannins). Polyphenols have dual effects: beneficial for nature and humans but harmful in high concentrations in wastewater. If not adequately treated in wastewater, polyphenols can threaten biodiversity, ecological balance, and water quality and pose a risk to human health. Effective management of these compounds in industrial waste is an urgent task for scientists. However, in a circular economy vision, the possibility of recovering polyphenols in large quantities represents an important challenge. Based on these premises, the purpose of the present work is developing and optimizing different bismuth-modified, easily recoverable materials composed of alginate spheres modified with a magnetic core and bismuth oxyhalides or Bi3+ ions as an active phase to recover and/or photodegrade polyphenols under solar light irradiation.
Here, we present our first results obtained using synthetic wastewater containing gallic acid (GA), 3,4,5-Trimethoxybenzoic acid (345TMBA), and 4-Hydroxybenzoic acid (4HBA) as model polyphenols. After adequately optimizing the conditions, 98% of polyphenols were collected, and the remaining part was effectively and quickly photodegraded
Innovative floating photocatalysts for sunlight harvesting: towards a sustainable water remediation, healthier lives, and reduced environmental impact for remote communities
No full textIntroduction
Owing to the exponential population growth, the increase in food demand is placing unprecedented pressure on the land and water resources of our planet [1]. In this context, water scarcity represents a complex problem, and the recent climate crisis has worsened living conditions in many parts of the world. In numerous countries, for many months of the year, people do not have enough affordable and safe water to meet their needs [2], and sometimes, to meet human needs, the environment is damaged. This issue is ever more pronounced in developing countries, where water scarcity is also responsible for numerous pandemic crises during which unsanitary conditions put patients and doctors at risk for disease transmission [3]. Although different technologies have been developed for water depollution (filtration, chemical or biological treatment, etc.), generally, they fail to remove contaminants of emerging concern (CECs) due to their high chemical stability. In the last few years, we have witnessed ubiquitous pollution from antibiotics and other emerging contaminants in hundreds of rivers worldwide, from the Thames to the Tigris. Therefore, developing new strategies capable of mitigating these scenarios becomes urgent. The Sun represents an essential resource in light of the dramatic energy crisis. It is an extremely powerful energy source, and sunlight is by far the most significant energy source on Earth. However, manufacturing photocatalytic materials that can exploit the entire solar spectrum for the photodegradation of pollutants is not easy. Moreover, to date, there is still no simple, economical, and accessible method that allows the application of photocatalysis for water purification in poor scenarios where people have little access to clean water.
Moreover, the most advanced materials reported in the literature are used as dispersed powder [4]. If, on one hand, working on fine powders has several benefits (high dispersion, impressive photoactivity, etc.), on the other hand, particular issues of primary importance need to be addressed. Therefore, photocatalyst immobilization strikes a compromise between the benefits of the photocatalysts and the necessity to ensure their appropriate application by improving stability and facilitating easier handling. Therefore, this topic is of crucial importance for the research communities. Floating photocatalysts give the advantage of maximizing both light utilization and surface aeration since they can float on the air-water interface. Their use also decreases the post-treatment cost. Here, we report the results obtained with the project "Water decontamination by sunlight-driven floating photocatalytic systems (SUNFLOAT)." Different safe, cheap, and highly efficient photocatalysts operating under solar irradiation were properly fabricated and immobilized on different synthetic and natural floating supports. These innovative materials were tested for the degradation of diverse classes of organic compounds (drugs, pesticides, and dyes) in different conditions. Finally, the final SUNFLOAT proof-of-concept (SPoC) device is described.
Material and Methods
All the materials and methods are reported in references [4-6].
Results and Discussion
Concerning the fabrication of highly performing photocatalysts in the visible part of the electromagnetic spectrum (that represents most of the solar irradiation), at first, conducting polymers (CPs)-based photocatalysts (polyaniline@TiO2 nanoparticles) were properly synthesized and supported on the surface of polyurethane (PU) foam [4]. CPs can act as excellent photosensitizers for traditional semiconductors, such as TiO2, thanks to their extended π-configuration system, which extends the TiO2 activity to the visible region. The fabricated water-floating polyaniline@TiO2@PU photocatalysts displayed extraordinary activity towards the photodegradation of rhodamine B (RHB, model dye) from the water matrix. Despite the widespread use of titanium dioxide (TiO2) nanoparticles in photocatalytic applications due to their properties, there is a growing interest in the scientific community to explore alternative materials. This shift is driven by concerns over the potential carcinogenic nature of TiO2 and its limited efficiency under solar light irradiation [7]. In this regard, graphitic carbon nitride (g-C3N4) has emerged as a metal-free visible photoactive semiconductor for water remediation. Its mid-wide bandgap of 2.7 eV, large surface area, excellent electrical and thermal conductivity, and high chemical stability make it ideal for photocatalytic purposes. At the same time, the possibility of replacing floating synthetic polymers with natural ones to support photocatalytic materials has paved the way for more sustainable devices for wastewater treatment. Based on these premises, biodegradable and biocompatible alginates are particularly interesting. They derive from brown seaweeds and can be used to immobilize photocatalysts under safe and mild conditions. Efficient, reusable floating-C3N4/alginate beads were successfully synthesized using two different precursors (urea and melamine) and applied for the photodegradation of different classes of organic pollutants (rhodamine B, diclofenac, and isoproturon) (5) Thanks to its extraordinary high surface area, alginate pearls modified with g-C3N4, synthesized by urea as the precursor, showed higher activity than that from melamine in the photodegradation of mixture of pollutants. The use of calcium alginate in fabricating photocatalytic beads presents a challenge: its abundant hydroxyl groups lead to strong adsorption of diclofenac transformation products, which in turn reduces the efficiency of active sites in degrading pollutants like rhodamine B and isoproturon. Despite this, these modified beads demonstrate promising activity and stability over five consecutive uses.
A limitation arises with floating-C3N4/alginate beads: the photocatalyst exposure on the bead surface is not maximized. In fact, g-C3N4, synthesized via a one-pot polycondensation method, is dispersed in the alginate solution, restricting surface exposure. This issue was addressed by replacing g-C3N4 with a TiO2-free semiconductor, BiOBr, prepared through co-precipitation on the bead surfaces [7]. This method yielded highly active floating photocatalysts, effective even against polyphenols.
However, alginate beads have a drawback: they are too degradable for extended reuse. Over time, their degradation leads to the gradual release of the catalyst into the solution, negatively impacting material performance and causing secondary pollution. For this reason, more stable natural floating supports were explored. Light-expanded clay aggregates (LECA) are cheaply manufactured from natural materials traditionally used in construction industries. LECA is extremely light, chemically inert, and thermally stable up to 1000°C. It is characterized by a low density and high porosity, conferring the ability to float on the water. BiOBr was grown on the surface of LECA beads, obtaining an extraordinary floating photocatalyst tested for CECs degradation under various environmental conditions: laboratory- and real-scale experiments.
For the realization of the SPoC device, this material was selected in combination with a proper container. In this regard, two different bowls were tested for real-scale tests: one made of transparent glass and the other of white polypropylene to verify the effect of light penetration in the photocatalytic process. Finally, the photocatalytic efficiency of the SPoC under natural sunlight irradiation was verified, and very promising results were obtained [6]. The findings suggest that BiOBr/LECA has the potential to serve as a promising sustainable alternative to traditional materials for potential applications for the degradation of CECs usually present in real surface waters to alleviate water contamination in critical contexts, such as those of vulnerable communities.
Figure 1: FESEM images of the (left) external and (right) internal part of BiOBr/LECA.
Conclusions
The SUNFLOAT project stands out for its real-world application, successfully utilizing actual sunlight, for water remediation. This breakthrough demonstrates the practical viability of floating photocatalysts like BiOBr/LECA and C3N4/alginate beads under natural solar conditions. Overcoming a common limitation in photocatalysis research, the project underscores the effectiveness of these innovative materials in harnessing solar energy for sustainable water purification. This real-sunlight functionality marks a significant step forward, offering a tangible, eco-friendly solution for improving water quality in remote communities facing water scarcity
Electrochemical and photocatalytic treatments: an innovative coupled strategy for simultaneous hydrogen production and wastewater remediation
No full textNowadays, the transition toward carbon-neutral energy production is imperative to mitigate climate change, ensuring a stable energy supply for the future generation1. Hydrogen (H2) is a promising energy storage medium, whose market is expected to increase exponentially due to its use as an energy vector in the transportation sector. Nevertheless, just 4% its production comes from electrochemical water splitting. In this context, the high potential required for the Oxygen Evolution Reaction (OER) constrains H2 evolution. Additionally, the use of noble metal-based electrodes complicates the practical application due to high costs and limited availability. In this frame, researchers are moving toward the development of noble metal-free electrodes mainly based on earth-abundant compounds.2 Regarding the anodic reaction, organic pollutants in wastewaters containing high level of chemical energy are excellent electrons donors and suitable candidates for producing H2 thanks to lower oxidation potential respect the one required for OER. For this reason, the electrochemical treatment of wastewater can represent a viable solution for hydrogen generation and simultaneous wastewater treatment, even if alone it is not sufficient. So, its coupling with other approaches can represent an interesting and efficient solution. Herein, we propose an innovative coupled process involving electrochemical treatment followed by heterogeneous photocatalysis for H2 generation using noble-metal free cathode and the simultaneous wastewater treatment. In general, electrochemical treatment alone resulted insufficient for wastewater complete mineralization. So, the photocatalytic step using bismuth oxychloride was exploited.2 This hybrid approach offers a novel and sustainable solution for energy generation and water purification in the face of increasing global industrialization and water scarcity
Nutrients enriched super absorbent polymers for the adsorption of water vapour
No full textIn the last years agricultural achieved impressive results. The doubling of agricultural food production was accompanied by greater inputs of fertilizer, water, new crop strains and pesticides, and other technologies of the “Green Revolution”. To meet the continuing demand for raw materials, developing countries now use more than 55 million tons of nitrogen fertilizers per year [1]. It is estimated that to reach adequate production of food for the growing population the external input of fertilizers will increase in the next years exponentially with negative impacts on sustainability and ecological principles [2].
Moreover, the uncontrolled release of large amounts of external nutrients have contributed to severe negative consequences (e.g., increased erosion, lower soil fertility, ground water and air pollution, rivers and lakes eutrophication, climate changes) [3]. In addition, water crisis is increasingly becoming a global problem with devastating consequences of, as evidenced by the recent drought experienced in Italy in the summer of 2022.
Among the most advanced materials developed to retain large quantities of water and fertilize the soil super absorbent polymers (SAPs), as potassium polyacryplated (K-PAs), occupy a special place for their unique features [4]. In fact, they are cheap, commercially available, non-toxic, harmless, non-polluting, and do not cause soil salinization [5].
However, to the best of our knowledges, the possibility of using K-PAs to recover water from industrial chimneys as vapor has never been studied. Similarly, nutrients-enriched K-PAs through modifications with recycled materials have never been developed.
In the present work we’ll describe our attempts in the modification of commercial K-PAs by waste materials and we’ll report the results obtained in their ability to adsorb water vapor
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