Biochar is a carbon-rich material produced from biomass pyrolysis whose properties can be tailored for various applications, including soil improvement, water purification, and catalysis. Its light absorption capacity also makes it promising for solar-driven processes like water evaporation. Photothermal membrane distillation (PMD) combines membrane separation with light-induced heating for efficient water purification. Unlike conventional membrane distillation, PMD utilizes light-absorbing materials to enhance vapor pressure and overcome temperature polarization, a common issue in membrane distillation. This study explored the potential of biochars and activated biochars, as filler materials for photothermal membranes, in line with circular economy principles. The mixed matrix membranes were prepared in a single step, via non-solvent induced phase separation starting from a uniform dispersion of the filler in a polyvinylidene fluoride solution. These materials exhibited great heating performance, reaching surface temperature up to 36 degrees C under a 125 W/m2 light source. Increasing the biochar loading up to 15 wt.% resulted in an 85% increase in distillation flux under light irradiation.

In this work, hollow fibre polyvinylidene fluoride (PVDF) supported membranes were prepared by dip coating a fibre glass sleeve in a PVDF solution, followed by precipitation via nonsolvent induced phase separation (NIPS) in 96% ethanol. The combination of these was optimized for obtaining membranes with a low-resistance thin polymeric layer and enhanced mechanical stability. The influence of both the withdrawal rate and the viscosity of the dope solution were investigated. The thickness of the PVDF coating layer was evaluated in the frame of the Landau-Levich model, which predicts that the film thickness results from the balance between viscous drag and surface tension forces. Among all the prepared membranes, the membranes prepared from a dope solution at 60 degrees C and with a withdrawal rate of 0.5 cm/s were selected to be used as support to grow biofilm for an application as Membrane Aerated Biological Reactor (MABR). The performance of the MABR, with the biofilm grown on the outer surface of the PVDF membranes and airflow supplied through the lumen of the fibre glass sleeve, was evaluated in terms of removal of Chemical Oxygen Demand (COD), ammoniacal nitrogen and total nitrogen. The MABR set up enabled the simultaneous abatement of the aforementioned parameters, with 78% of removal for COD, 21% for ammonia and 5% for total nitrogen, an interesting starting point for lab-made membranes exploited for this application.

Electrocatalyst performance is often treated as an intrinsic property of the catalyst, although the measured activity depends strongly on the catalyst ink formulation and how the electrode is constructed. This suggests that the catalyst ink design rules established for one catalyst may not translate to other materials. Yet, the design rules for benchmark electrocatalysts are often adapted for structurally distinct materials. Here we use Bayesian optimization over a five-dimensional formulation space (water/ethanol/isopropyl alcohol ratio, ionomer loading, catalyst content and sonication time) to map the ink formulation landscape in alkaline media for two contrasting oxygen evolution reaction catalysts: crystalline IrO2 nanoparticles, the benchmark anode catalyst, and a porous NiFe metal-organic framework. The optimal IrO2 ink exhibits a smooth response surface near the optimum, whereas the metal-organic framework shows a highly non-convex response surface, with performance highly sensitive to the ionomer content. The optimal solvent composition also markedly differs between the two catalysts, with the IrO2 preferring an ethanol-rich medium while the metal-organic framework prefers isopropyl alcohol. Turnover frequency analysis of the metal-organic framework-based catalyst reveals that the ink formulation can alter the quality of the active sites, not merely their number. These results demonstrate that ink rules developed for oxide catalysts do not directly transfer to porous framework-based electrocatalysts. Bayesian optimization therefore provides a data-efficient route to catalyst-specific electrode formulation. In addition, our results highlight ink preparation as a decisive variable in electrocatalyst benchmarking.

This study focuses on the synthesis of metallic magnetic nanosystems embedded in mesoporous silica (SiO2), and the impact of matrix porosity, controlled by temperature treatment, on the efficiency of H2 reduction process. The reduction of FeCo oxides to the corresponding alloy nanosystems was first optimized, identifying FeCo with 50 at% Fe as the optimal composition due to its high saturation magnetization (∼242 A m2 kg-1) and oxidation onset temperature (∼440 °C). Then, the FeCo-oxide nanocomposites were synthesized into SiO2via sol-gel self-combustion under thermal treatments, to properly tune the surface area of the silica matrix. By controlling the annealing temperature, the specific surface area (SA) of the matrix decreases from ∼512(1) m2 g-1 to ∼345(1) m2 g-1 when annealed to 900 °C in air. Following topochemical reduction in H2, the structural properties of the obtained FeCo-SiO2 nanocomposites have been analyzed using X-ray powder diffraction and magnetic properties were evaluated to establish a correlation between matrix SA and reduction capability. The decrease of SA leads to incomplete reduction at higher temperatures, with the formation of FeYOX/CoXOY intermediates. This work underscores the critical role of matrix porosity in achieving a delicate balance to ensure both the efficient conversion of nanostructured oxide to their metallic state and the preservation of their magnetic and structural integrity.

This study investigates the generation of hydroxyl radicals ((OH)-O-center dot) using the biochar-packed column flow system for methylene blue (MB) degradation in the presence of oxygen. Electron paramagnetic resonance (EPR) was employed to quantify and analyse the stability of carbon-centred permanent free radicals (PFRs) in the solid state (1017-1019 spins per g). In water, PFRs act as catalysts for the generation of hydroxyl radicals ((OH)-O-center dot), which are responsible for the advanced oxidation process (AOP) of organic molecules. Bamboo-based activated carbons (BACs) were produced through fast pyrolysis at various temperatures ranging from 300 to 800 degrees C, with the gas environment switched from N2 to CO2. The BAC treated at 400 degrees C (B400), which balanced physicochemical properties (lower surface area, larger micropore volume, and higher formation of reactive oxygen species in water), demonstrated the highest performance in removing MB compared to B500 and B600. The efficiency of MB removal depended on the presence of (OH)-O-center dot in aerated or purged solutions, and the crucial role of dissolved oxygen in the formation of (OH)-O-center dot was established. Additionally, the study explores the kinetics of MB removal, emphasising the predominance of chemical mechanisms such as electron transfer reactions and PFR-mediated oxidative degradation. This work provides valuable insights into the potential application of BACs for environmental remediation, particularly in treating dye-contaminated wastewater, eliminating the need to add H2O2 as a chemical source of reactive oxygen species (ROS) in solution.

The electrochemical hydrogen compressor (EHC) offers an effective solution for hydrogen transport challenges, enabling simultaneous purification and compression, even when hydrogen is blended with natural gas at low concentrations. This study investigates the impact of three commercial Nafion (R) membrane types (Nafion (R) 117, Nafion (R) 115, and Nafion (R) 212) on the separation efficiency of EHC, examining the influence of temperature, methane concentration, and hydrogen flow rate, thereby providing a comprehensive evaluation of membranespecific performance on the EHC's efficiency. Nafion (R) 212 demonstrated superior energy efficiency due to its lower thickness and higher ion-exchange capacity. Tests with a 90:10 methane:hydrogen molar ratio revealed an energy consumption of 2.30 kWh & sdot;kg- 1H2 and hydrogen purity exceeding 99 %. The experimental results were validated with a mathematical model incorporating key parameters from existing literature, achieving an average deviation of 2.5 % between the model and experimental data.

The high cost and low energy efficiency of conventional water electrolysis methods continue to restrict the widespread adoption of green hydrogen. Anion exchange membrane (AEM) water electrolysis is a promising technology that can produce hydrogen using cost-effective transition-metal catalysts at high energy efficiency. Herein, we investigate the catalytic activity of nickel and iron nanoparticles dispersed on metal-oxide supports for the oxygen evolution reaction (OER), employing electrochemical testing with an anion exchange ionomer to evaluate their potential for application in AEM electrolyzers. We report the electrochemical performance of NiFe nanoparticles of varying Ni:Fe ratios on CeO2 for OER reaction, assessing the overpotential, Tafel slope, and electrochemical stability of the catalysts. Our findings indicate that Ni90Fe10 has the highest catalytic activity as well as stability. To further understand the role of different supports, we assess the electrocatalytic performance of Ni90Fe10 nanoparticles on two more supports - TiO2 and ZrO2. While CeO2 has the lowest overpotential, the other supports also show high activity and good performance at high current densities. TiO2 exhibits superior stability and its overpotential after chronopotentiometry measurements approaches that of CeO2 at high current densities. These results underscore the critical role of iron addition in enhancing nickel nanoparticles' catalytic activity and further emphasize the importance of metal oxide supports in improving catalyst stability and performance.

BACKGROUND: Catalysts based on alumina-supported metal oxides are of crucial importance in the field of heterogeneous catalysis for several applications requiring tuning of surface acidity.RESULTS: In this work, the effects of K+, Ca2+ and La3+ cation doping have been evaluated on a well-characterized commercial gamma-Al2O3 through morphological characterization and surface characterization (Brunauer-Emmet-Teller, X-ray diffraction, field emission scanning electron microscopy, Fourier transform infrared spectroscopy). The conversion of ethanol as a test reaction was performed over these catalysts. The impregnated oxide species essentially remain at the surface, resulting in the partial poisoning of the strongest alumina Lewis acid sites. Moreover, oxide anions may increase basicity at the surface. The doping results in a significant decrease in catalytic activity in ethanol conversion to diethyl ether and to ethylene, which is shifted at higher temperatures. On the other side, higher activity in the formation of C4 olefins was detected, namely on the K-doped alumina.CONCLUSION: The partial poisoning of the strongest alumina Lewis acid sites and the presence at the surface of new more basic cation-anion couples result in significant changes in catalytic ethanol conversion.(c) 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).

Ti3C2Tx MXene is one of the most comprehensively studied 2D materials in terms of its adsorptive, transport, and catalytic properties, cytotoxic performance, etc. Still, conventional MXene synthesis approaches provide low single-flake MXene yield and frequently uncontrollable properties, demanding further post-processing. The MXene family also lacks magnetism, which is helpful for producing effective nanoadsorbents as their magnetic decantation is the cheapest and most convenient way to remove the spent adsorbent from water. Composite materials consisting of magnetic nanoparticles grown on top of MXene flakes are commonly used to provide magnetic properties to the resulting nanocomposite. In this paper, we study the possibility to delaminate multilayer Ti3C2Tx MXene sheets directly by growing iron oxide magnetic nanoparticles inside their interlayer spacing. We find out that, with a mass fraction of particles comparable or exceeding that of MXenes, their growth is accompanied by an effective enhancement of single-layer MXene yield and suitable magnetic properties of the resulting composite. The developed approach can be further used for simplifying synthesis protocols to obtain magnetic MXene-based nanoadsorbents with tunable properties.

Hollow fibers (HFs) provide a number of advantages in comparison with traditional flat sheet (FS) membranes. The ability to pack them closely enables the creation of modules with a large specific surface area. Furthermore, this geometry does not require any support material and offers excellent mechanical properties. Nonsolvent induced phase separation (NIPS) is the most used method for HF spinning. However, the parameters commonly used for FS manufacturing cannot be simply translated to HF production since there is a far greater number of factors that may be adjusted to produce membranes with the desired properties. In this study, HFs are prepared by means of the NIPS technology using polyvinylidene fluoride (PVDF) as polymer and dimethyl sulfoxide as solvent. The surface and cross-section characteristics are tailored by tuning the nonsolvent strength (i.e., by using pure water or water/ethanol solutions). Nearly dense selective skins, suitable for gas separation processes, can be obtained when harsh nonsolvents are used, whereas porous and more symmetric structures, suitable for membrane filtration systems, are formed with weaker nonsolvents. Finally, the effect of the dope solution concentration is evaluated, registering a decrease of the membrane porosity as the polymer amount is increased.

Membrane engineering is going to be strategic to meet the challenges for a more sustainable process industry and fluid waste stream treatment aimed at the zero-liquid discharge approach. The heart of several emerging membrane technologies is a hydrophobic membrane. This chapter will begin by introducing the basics of hydrophobicity on membranes, then an indication of the main commercial hydrophobic membranes available in the market will be provided. Afterwards, in the chapter, the main preparation approaches of hydrophobic membranes will be illustrated including sintering, stretching, electrospinning, and phase inversion techniques. Finally, several processes based on the application of hydrophobic membranes will be briefly discussed in order to appreciate their role and provide an idea of the application flexibility that they feature.

This study explores the potential of using basalt reinforced UHPC by incorporating simultaneously self-cleaning and self-luminescent features, paving the way for sustainable advancements in civil engineering. New green formulations of UHPC were developed by integrating supplementary cementitious materials and optimizing water to the binder ratio, followed by using basalt fibers to enhance strength and ductility. The fabricated samples with high particle-packing density exhibit sufficient workability and compressive strength up to 136 MPa, and, when incorporating basalt fibers, a notable reduction in brittleness. The inner microstructure of basalt fibers was observed to be smooth, homogeneously distributed, and well adhered to the UHPC matrix. To ensure the desired long-lasting visual appearance of decorative UHPC and reduce future maintenance costs, a time-effective strategy for creating a light-emitting biomimetic surface design was introduced. The samples exhibit high surface roughness, characterized by micro to nano-scale voids, displaying superhydrophobicity with contact angles reaching up to 155.45°. This is accompanied by roll-off angles decreasing to 7.1°, highlighting their self-cleaning features. The self-luminescence feature showcased intense initial light emission, offering a potential energy-efficient nighttime lighting solution.

Background/Objectives: Three-dimensional (3D) cell culture technologies allow us to overcome the constraints of two-dimensional methods in different fields like biochemistry and cell biology and in pharmaceutical in vitro tests. In this study, a novel 3D hydrogel sponge scaffold, composed of a crosslinked polyacrylic acid forming a porous matrix, has been developed and characterized. Methods: The scaffold was obtained via an innovative procedure involving thermal treatment followed by a salt-leaching step on a matrix-containing polymer along with a gas-forming agent. Based on experimental design for mixtures, a series of formulations were prepared to study the effect of the three components (polyacrylic acid, NaHCO3 and NaCl) on the scaffold mechanical properties, density, swelling behavior and morphological changes. Physical appearance, surface morphology, porosity, molecular diffusion, transparency, biocompatibility and cytocompatibility were also evaluated. Results: The hydrogel scaffolds obtained show high porosity and good optical transparency and mechanical resistance. The scaffolds were successfully employed to culture several cell lines for more than 20 days. Conclusions: The developed scaffolds could be an important tool, as such or with a specific coating, to obtain a more predictive cellular response to evaluate drugs in preclinical studies or for testing chemical compounds, biocides and cosmetics, thus reducing animal testing.

Mixed matrix membranes (MMMs) combine the advantages of inorganic fillers with those of polymeric matrix and, in the last few years, have been widely studied, thanks to their potential to overcome some of the main limiting factors of both polymeric and inorganic membranes. The increasing availability of new fillers allows the preparation of membranes with improved properties, in terms of both better stability and separation performance. One of the main advantages of MMMs is that they couple the easy of processability and the low cost of polymeric membranes with the selectivity and stability of inorganic ones. Therefore, it is possible to use a traditional phase separation technique to prepare a membrane with enhanced performance. However, integrating an inorganic filler in a polymeric matrix comes with some drawbacks: the scarce compatibility between the two phases can create defects and a loss of selectivity. Therefore, the selection of a suitable filler and the surface modification procedures are vital to prepare MMMs with no defects. This chapter will describe the most common fillers used for MMMs preparation, some surface modification techniques, and finally, the application of MMMs in different fields will be reviewed.

Abstract A magnetic perovskite-spinel oxide nanocomposite synthesized through a sol–gel self-combustion process is used for the first time as an adsorbent to remove toxic heavy metals (i.e., Pb2+). The synthesized LaFeO3:CoFe2O4 ((LFO)1:(CFO)x) (x = 0.11–0.87) nanocomposites possess good stability, abundant oxygenated active binding sites, and unique structural features, making them suitable for removing divalent Pb2+ ions. Scanning electron microscopy, X-ray diffraction, BET surface area, magnetization measurements, zeta-potential analyses, and X-ray photoelectron spectroscopy were used to analyze the nanocomposites, and their structural changes after Pb2+ ions adsorption. Batch tests confirmed that (LFO)1:(CFO)x efficiently removes Pb2+ from water with a maximum adsorption capacity of 105.96 mg/g. The detailed quantitative study indicates that the interaction of hydroxyl groups with Pb2+ ions occurs through electrostatic interactions and complex formation. We also demonstrate a new ring-magnetic separator system that allows magnetic separation of the toxic ions at a higher speed compared to traditional block magnets. The unique structure, high porosity, large specific surface area, and oxygenated functional groups of (LFO)1:(CFO)x nanocomposites make them promising materials for removal of heavy metal ions and possibly other environmental pollutants. This study provides a new approach to preparing nanocomposites of magnetic spinel ferrites with perovskite oxides for environmental applications.

Water shortage is a severe global problem that is worsening because of both climate change and world population increase. A viable solution could be the improvement of desalination technologies and the implementation of renewable energy exploitation. Since membrane distillation ensures a complete rejection of non-volatile substances and does not require high feed temperatures, it might be a practical and sustainable option in this context.In a novel configuration known as photothermal membrane distillation (PMD), solar light is converted into heat by a photoactive membrane, significantly minimising temperature polarisation effects and feed temperature reduction along the module.In this study, a PMD plant operating in sweeping gas configuration was assembled and tested in a real situation. The system was monitored during different seasons to assess the impact of various weather conditions on the performance. Solar irradiation was a main variable; in daylight hours the distillate flux was increased by almost 50% thanks to the photothermal properties of the membrane, reaching a maximum productivity of 1.5 kg/m2h. Another important parameter was air humidity, since ambient air was used as inert sweeping gas. Flux variations were further induced by seasonal fluctuations of other weather conditions such as ambient temperature.

The present study deals with the synthesis, characterization and performance evaluation of ferric and clayey membranes made from Iron ore and Bentonite as feedstock's materials. This work sheds light on the development of new series of ferric and clayey membranes with different percentage composition of raw materials, organic and inorganic additives were synthesized and consolidated by thermal treatment to get ceramic membranes. A kinetic losses process allowed us to select twelve membranes potentially eligible since the intervention of organic additives and their contribution to the microstructure of the membranes. Density and porosity studies permitted to choose the optimal ferric and clayey ceramic membrane formulation. A fabricated ferric membrane (made from 80 wt% iron, 6 wt% clay, 4 wt% me ' thocel, 4 wt% amijel, 4 wt% starch and 2 wt% PVA after sintering at 900 degrees C) showed the highest total porosity of 62.79 % and apparent porosity of 61.02 %. The selected clayey membrane (made from 86 wt% clay, 6 wt% me ' thocel, 4 wt% amijel, 4 wt% starch after sintering at 900 degrees C) has 64.95 % of total porosity and 49.3 % of apparent porosity. The regeneration of both types of ceramic membranes was finally assessed. The results obtained show that may the membrane technology is still young however it has great potential for further improvements.

The transfer of oxygen is limited at the gas/liquid interface by the low solubility of oxygen in water. Fine bubble diffusers have a standard oxygen transfer efficiency (SOTE) lower than 30% in a full-scale system. Porous membranes can be employed as diffusor to improve the efficiencies taking the advantage of the high exchange interfacial area and the low volume of equipment. The aim of this work is to study the feasibility of membrane systems for aeration in a full-scale system. Several membrane modules were prepared using hollow fibers hydrophobic membranes and compared with the traditional disk diffusor currently employed in wastewater treatment. The mass transfer coefficient (KLa) and SOTE were assessed by carrying out the aeration tests in both lab-scale and full-scale systems exploring different operating parameters such as system flow rate, the geometry of the module and the surface of the device. The advantage and disadvantages of employing membranes in the aeration process were highlighted. The membrane unit showed better overall mass transfer efficiency increasing from 28% at the lab-scale to 34% in the full-scale system. Unlike the conventional disk diffusers, it has been found that the membrane aerator can operate with significantly lower air flow rates, which leads to a doubling of the efficiency. Moreover, the membrane surface generating the bubbles can be easily increased while maintaining the same module footprint, which in turn allowing a further increase of efficiency from 9% to 24%. However, important phenomena of scaling were observed on the membrane surface.

Ceramic membranes prepared with flat sheet configuration using local materials, iron ore and bentonite, are reported in this investigation. The feedstocks used were fully characterized using X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS) and laser diffraction/light scattering. In order to optimize the preparation conditions, the effect of sintering temperature on the microstructure of ferric and clayey membranes was assessed. Results obtained with SEM, confirmed by optical microscopy, indicate that the optimized sintering temperature was in the vicinity of 900 °C. The properties of the fabricated membranes were characterized in terms of mass and thickness loss throughout a determined period of time. The experimental results present a negligible variation in the rate of mass change, which suggested the stability of the synthesized membranes. Both the ferric and clayey membranes exhibit a prevalence of mesopores in their pore distribution. These results suggest that these specific membranes could be employed as cost-effective and environmentally friendly materials. Furthermore, they hold promise for potential applications in gas treatment processes.