Alternative Process Research Articles

Arsenic mobilization across the sediment-water interface of the Three Gorges Reservoir as a function of water depth using DGT and HR-Peepers, a preliminary study

The artificial regulation of the Three Gorges Reservoir (TGR) creates large water level fluctuation zones (WLFZ) that may change the behavior of metals and metalloid in sediment, particularly redox sensitive elements. Mobilization of As, Fe and Mn across the sediment-water interface (SWI) in the TGR as a function of different water depth (periodically and permanently submerged sediments, respectively) was in situ determined by diffusive gradients in thin films (DGT) and high-resolution dialysis technique (HR-Peeper), respectively. The results showed that the mobilization of As was significantly affected by Fe/Mn especially Mn, across the SWI. Duo to the oxic-anoxic transitional state in near bottom water, the reduced Fe and Mn in sediment pore water could be oxidized and precipitated again, leading to the co-precipitation of As with Fe/Mn oxides (hydroxides). Consequently, concentrations of As, Fe and Mn in labile phases and pore water were generally low across the SWI, then they sharply increased at a few centimeters below the SWI. Considering different water depth, various trends were found in labile phase, whereas concentrations of As, Fe and Mn in pore water in permanently submerged sediments were significantly higher than those in periodically submerged sediments. The dry-re-wetting alternation processes in the WLFZ may play vital roles in the resupply capacity of sediments as it was found that periodically submerged sediments with longer re-wetting time had higher Fe/Mn resupply capacity than those with shorter re-wetting times and permanently submerged sediments.

Mulberry (Morus alba L.) leaf powder modified the processing of meat alternatives: Principal component analysis from apparent properties to chemical bonds

For texture control in plant-meat alternatives, the interrelationship between apparent characteristics and chemical bonds in high-fiber formulations remains unclear. The influence of mulberry leaf powder on apparent characteristics and chemical bonds of raw materials, block and strip products at addition amounts of 0.5–25% was analyzed. The results showed that 8% addition significantly increased the chewiness of the block by 98.12%. The strips' texture shows a downward trend, and the processing produced more redness and color difference. Additives promoted the formation of voids, lamellar and filamentous structures, and the strip produced more striped structures. Disulfide bonds significantly increased in the block, and the β-turn in the secondary structure enhanced by 12.20%. The β-turn transformed into a β-sheet in strips. Principal component analysis revealed that the texture improvement was associated with producing disulfide bonds and β-turn, providing a basis for high-fiber components to improve products' apparent characteristics by chemical bonds.

Alternative and Classical Processes for Disinfection of Water Polluted by Fungi: A Systematic Review

The introduction of the first list of priority pathogenic fungi by the World Health Organization stresses the need to research and develop public health actions to mitigate infections caused by fungi. One of those actions involves the water disinfection systems, which comprise classical and alternative methods that have been developed in the last decades. Thereby, this work reviews the disinfection of fungi by classical methods such as chlorination, ozonation, and ultraviolet (UV) treatments and alternative advanced oxidation processes (AOPs) such as photo-Fenton, photocatalysis, or couplings of UV with peroxides. The matrices of aquatic systems (sewage, groundwater, drinking water, among others) were considered. A bibliometric analysis is performed initially, and then some aspects of the resistance to antifungals are presented, and the efficiency of the diverse processes in the reduction in fungal loading is also revised. Herein, it is shown the role of the disinfecting agents (e.g., chlorine, hydroxyl radical, or light) and their effects on fungi structures (e.g., direct DNA damage, or indirect damage due to the action of radicals). Moreover, gaps, such as the treatment of antifungal-resistant fungi and limited information about combinations among AOPs, related to the disinfection of water polluted by fungi, were identified.

Basal endothelial glycocalyx's response to shear stress: a review of structure, function, and clinical implications.

The endothelial glycocalyx encompasses the entire endothelial cell, transducing extracellular signals and regulating vascular permeability and barrier functions. The apical glycocalyx, which forms the lumen of the vessel, and the basal glycocalyx, at the smooth muscle cell interface, are often investigated separately as they are exposed to vastly different stimuli. The apical glycocalyx directly senses fluid shear forces transmitting them intracellularly through connection to the cytoskeleton of the endothelial cell. The basal glycocalyx has demonstrated sensitivity to shear due to blood flow transmitted through the cytoskeleton, promoting alternate signaling processes. In this review, we discuss current literature on the basal glycocalyx's response to shear stress in the context of mechanotransduction and remodeling. The possible implications of basal glycocalyx degradation in pathologies are also explored. Finally, this review seeks to highlight how addressing the gaps discussed would improve our wholistic understanding of the endothelial glycocalyx and its role in maintaining vascular homeostasis.

Solid State Reaction Epitaxy, A New Approach for Synthesizing Van der Waals heterolayers: The Case of Mn and Cr on Bi2Se3

AbstractVan der Waals (vdW) heterostructures that pair materials with diverse properties enable various quantum phenomena. However, the direct growth of vdW heterostructures is challenging. Modification of the surface layer of quantum materials to introduce new properties is an alternative process akin to solid state reaction. Here, vapor deposited transition metals (TMs), Cr and Mn, are reacted with Bi2Se3 with the goal to transform the surface layer to XBi2Se4 (X = Cr, Mn). Experiments and ab initio MD simulations demonstrate that the TMs have a high selenium affinity driving Se diffusion toward the TM. For monolayer Cr, the surface Bi2Se3 is reduced to Bi2‐layer and a stable (pseudo) 2D Cr1+δSe2 layer is formed. In contrast, monolayer Mn can transform upon mild annealing into MnBi2Se4. This phase only forms for a precise amount of initial Mn deposition. Sub‐monolayer amounts dissolve into the bulk, and multilayers form stable MnSe adlayers. This study highlights the delicate energy balance between adlayers and desired surface modified layers that governs the interface reactions and that the formation of stable adlayers can prevent the reaction with the substrate. The success of obtaining MnBi2Se4 points toward an approach for the engineering of other multicomponent vdW materials by surface reactions.

Parametric Study of Die Sinking EDM of H13 Steel using Taguchi Techniques

As for H13 die steel, it is distinguished by a high hardness and a unique surface characteristics that must be created during machining using non-standard methods. One of such non conventional manufacturing techniques involving the use of Electrical Discharge Machining (EDM) for machining complex or hard material parts. It indicates that EDM has progressed from a series of a tool and die process to an alternative micro-scale application machining process. The paper is aimed at elaborating mathematical models defining the link between the MRR and SR to measured input parameters (current, pulse-on time, pulse-off time, and Reference voltage) in hot work steel EDM. With a L9 orthogonal involving four variables at three levels were used. The values of the model quality factors analyzed by the ANOVA procedure show that the selected mathematical models describe the process performance within successfully studied range with high level of precision. To determine the optimal condition, Taguchi method was used to measure the performance impact of different process parameters and find out best mixing. Minitab V 21 software has been used for the analysis and explanations. A good agreement between experimental value and the predicted one was found.

Effective Natural Language Processing Algorithms for Early Alerts of Gout Flares from Chief Complaints

Early identification of acute gout is crucial, enabling healthcare professionals to implement targeted interventions for rapid pain relief and preventing disease progression, ensuring improved long-term joint function. In this study, we comprehensively explored the potential early detection of gout flares (GFs) based on nurses’ chief complaint notes in the Emergency Department (ED). Addressing the challenge of identifying GFs prospectively during an ED visit, where documentation is typically minimal, our research focused on employing alternative Natural Language Processing (NLP) techniques to enhance detection accuracy. We investigated GF detection algorithms using both sparse representations by traditional NLP methods and dense encodings by medical domain-specific Large Language Models (LLMs), distinguishing between generative and discriminative models. Three methods were used to alleviate the issue of severe data imbalances, including oversampling, class weights, and focal loss. Extensive empirical studies were performed on the Gout Emergency Department Chief Complaint Corpora. Sparse text representations like tf-idf proved to produce strong performances, achieving F1 scores higher than 0.75. The best deep learning models were RoBERTa-large-PM-M3-Voc and BioGPT, which had the best F1 scores for each dataset, with a 0.8 on the 2019 dataset and a 0.85 F1 score on the 2020 dataset, respectively. We concluded that although discriminative LLMs performed better for this classification task when compared to generative LLMs, a combination of using generative models as feature extractors and employing a support vector machine for classification yielded promising results comparable to those obtained with discriminative models.

Impact of Pickering Emulsions Composition on Lipase Catalyzed Peroxyacetic Acid Synthesis

AbstractDue to the need for environmental protection and sustainability, there has been a rising need to replace the traditionally harsh oxidative functionalization process, which is essential for syntheses of various organic compounds, by biocatalysis. However, the investigated alternative processes are still challenged with enzyme instability and/or low specific reaction rate. Due to these still existing challenges and the recognition of Pickering emulsions as an efficient platform for continuous biphasic biocatalysis, the first, enzymatic step of the lipase catalyzed oxidative functionalization was investigated in bioactive Pickering emulsions. The study focused on the impact of Pickering emulsion composition such as the volume phase fraction, type and concentration of the nanoparticles and enzymes on continuous peroxyacetic acids synthesis. The type of nanoparticles used and Candida antarctica lipase B concentration significantly impacted the process while the other named parameters only had a marginal influence.

Electrocoagulation treatment of sugarcane vinasse: Operating parameters and cost analysis by response surface methodology

The production of ethanol biofuel using sugarcane as substrate generates vinasse as the main wastewater from the fermentation–distillation process. The Brazilian legislation allows the use of vinasse for fertigation in limited volumes, and the remaining effluent must be treated prior to its reuse or discharge into the environment. The study aimed to evaluate the electrocoagulation (EC) technique as an alternative treatment process for raw sugarcane vinasse. The effects of the electrode gap (1–3 cm), applied electric charge (0–39000 C/L), current density (2.2–20 mA/cm2), and stirrer speed (0–680 rpm) were evaluated in a batch electrolytic reactor with aluminum electrodes. The evaluation results revealed that dissolved solids were removed and the pH increased during electrolysis in all experimental conditions, which suggested that EC was suitable for the pH neutralization of vinasse without the requirement of salt addition. An electrode gap of 1 cm and a current density of 2.2 mA/cm2 resulted in the lowest electric energy consumption (11.0 kW h/m3) and the lowest increment in the electrolyte temperature (9.5 °C). High vinasse clarification was achieved under the optimal operating conditions of 1 cm electrode gap, 31,000 C/L applied electric charge, 6.1 mA/cm2 current density, and 430 rpm stirrer speed, with 13.5 kW h/m3 and 2.88 kg Al/m3 of consumption. The treatment cost was calculated to be 6.95 US$/m3, from which the electrode dissolution was determined to be 75%. The sludge settling velocity was 0.14 cm/min, which suggested poor sedimentability, possibly due to bubble gas adsorption on the surface of the formed flocs. Results of the proposed operational parameters indicate that EC can be used as a pre-treatment of vinasse, adapting the main sugarcane processing wastewater biotechnological use.

Nanoimprint lithography for grayscale pattern replication of MEMS mirrors in a 200 mm wafer

In this work a multilevel nanoimprint lithography (NIL) replication process was demonstrated to produce 1D MEMS mirrors employing vertical asymmetric comb-drive electrostatic actuation, in a 200 mm wafer SOI-based process. In comparison with a direct write laser (DWL) grayscale lithography step (which for the proposed layout requires around 40 h of exposure time per wafer), this NIL method greatly enhances fabrication throughput by reliably reproducing a master's multilevel topography onto the photoresist. This study describes the NIL master fabricated using grayscale lithography, the working stamp, and the replication micromachining processes. An extensive characterization of the morphology and topography of the intermediate working stamp is provided, along with an optimization study of the replica fabrication and the alignment procedure between the replica and the mirror substrate. The MEMS device pattern was effectively replicated, exhibiting electrode gaps of 3.66 μm (grayscale process yields gaps of 3.5 μm). Discrete photoresist levels of 1.53 μm and 2.83 μm were observed, with a misalignment to the preceding metal layer of 5 μm and 10 μm in the x and y directions, respectively. These deviations were found to be within the required alignment margin defined by the layout (20 μm). The 1D MEMS mirror fabricated using this NIL process was successfully characterized using Scanning Laser-Doppler Vibrometry under atmospheric pressure conditions. The results obtained were in accordance with the theoretical design parameters, demonstrating that NIL can be successfully used as a fast, low-cost alternative lithography process to fabricate multilevel MEMS structures.

The influence of negative urgency and mood inductions on alcohol cognitions.

Negative urgency (NU), the tendency to act rashly during negative emotional states, is a robust risk factor for alcohol misuse that is posited to function in part through alcohol-related cognitions. Nonetheless, relatively little research has examined mood-based fluctuations in such cognitions, which could help to explain how the trait of NU translates to impulsive alcohol-related behaviors. We examined how NU impacted several alcohol cognitions (positive/negative alcohol expectancies, positive/negative alcohol valuations, and alcohol craving for positive/negative emotional reinforcement) before and after negative, neutral, or positive mood inductions. We hypothesized that NU would predict greater and more favorable endorsement of alcohol and its effects following negative (vs. positive or neutral) mood induction. Participants (N = 428) were southern-midwestern college students recruited for an online experiment. Following the provision of consent, participants rated NU and preinduction alcohol cognitions, and were then randomly assigned to one of three (negative, neutral, or positive) mood inductions; subsequently, postinduction alcohol-cognition ratings were immediately obtained. We conducted six robust multilevel linear models (one per DV) examining NU's influence on within-person changes in alcohol cognitions across each mood induction. No three-way interactions were identified and only one two-way interaction involving NU was identified. There were main effects across mood induction conditions and time points for NU predicting greater endorsement of positive and negative alcohol outcome expectancies, and greater alcohol craving for positive and negative emotional reinforcement. Greater NU predicts greater perceived likelihood of alcohol's effects, alongside greater desire for mood improvement from alcohol. The absence of three-way interactive effects indicates NU's influence on mood-dependent fluctuations in alcohol cognitions may manifest over longer timescales (e.g., months and years), involve alternative cognitive processes (e.g., drinking motives and implicit alcohol cognitions), and apply more broadly to desires for mood improvement than purely negative emotional reinforcement.

Energy demand distribution and environmental impact assessment of chitosan production from shrimp shells

Step towards resilience and sustainability through exploring renewable biomass and waste streams to produce higher-added value products and energy is among key aspects for closing the loops, saving resources, and reducing the resource and emission footprints. In that respective, crustacean shells waste can offer rich spectre of valuable compounds such as proteins, chitin, carotenoids. This waste is produced in large quantities worldwide, thus allowing for commercial valorisation. An overview of technologies is undertaken for more sustainable and environmentally friendly chitosan production via chitin isolation and conversion and compared to the conventional processes. Furthermore, an assessment of the environmental burden and energy demand distribution for conventional and more sustainable alternative processes was performed, based on lab-scale experimental data. Three different chitin extraction routes and three distinct chitosan conversion processes were considered and compared for their greenhouse gas footprint, abiotic depletion, acidification, eutrophication and other potentials. Finally, the energy demand distribution was analysed considering electricity production patterns from three European countries, Slovenia, Portugal and Norway. The results showed that alternatives 3-A and 3-B (conventional eco-solvents - conventional deacetylation with 40 % and 50 % NaOH) generate the lowest environmental burden (184 g CO2 eq./g chitosan). Electricity was the main hotspot of the processes, used either for extraction, plasma treatment or deacetylation. The sensitivity analysis proved that the Norwegian electricity mix has the lowest environmental impact (4.2 g CO2 eq./g chitosan). This study highlights the impact of blue biorefineries by transforming marine waste to valuable biopolymers such as chitin and chitosan.

Enhanced electrochemical oxygen generation from sillenite phase of bismuth iron oxide (Bi24Fe2O39) ultrafine particles stabilised at room temperature

Recently, lot of research is going on in development of clean energy-based technology to address the issue of exponentially increasing energy demands. Electrochemical water splitting is a clean and efficient process for generation of H2 and O2. Water electrolysis produces hydrogen and oxygen on cathode and anode respectively as separate half-cell reactions is one of the most important clean alternative processes. This work reports synthesis of Bi24Fe2O39 ultrafine crystalline nanoparticles via facile room temperature chemical method for the first time. Bi24Fe2O39 shows a spherical morphology with an average size of 8 nm. As obtained Bi24Fe2O39 acts as an electrocatalyst for electrochemical oxygen evolution reaction (OER). Electrochemical oxygen generation studies confirm the overpotential of 420 mV in 1 M KOH solution at a current density of 10 mA/cm2. Tafel slope and EIS studies give further insight of oxygen generation process. The results show that Bi24Fe2O39 exhibits low Tafel slope of 63 mV dec−1 and a very low charge transfer resistance of ∼10 Ω. This study paves a new way for future research into bismuth based sillenite structure for various energy related applications.

Spaced Double Hydrogen Bonding in an Imidazole Poly Ionic Liquid Composite for Highly Efficient and Selective Photocatalytic Air Reductive H2O2 Synthesis

AbstractPhotocatalytic oxygen reductive H2O2 production is a promising approach to alternative industrial anthraquinone processes while suffering from the requirement of pure O2 feedstock for practical application. Herein, we report a spaced double hydrogen bond (IC−H‐bond) through multi‐component Radziszewski reaction in an imidazole poly‐ionic‐liquid composite (SI‐PIL‐TiO2) and levofloxacin hydrochloride (LEV) electron donor for highly efficient and selective photocatalytic air reductive H2O2 production. It is found that the IC−H‐bond formed by spaced imino (−NH−) group of SI‐PIL‐TiO2 and carbonyl (−C=O) group of LEV can switch the imidazole active sites characteristic from a covered state to a fully exposed one to shield the strong adsorption of electron donor and N2 in the air, and propel an intenser positive potential and more efficient orbitals binding patterns of SI‐PIL‐TiO2 surface to establish competitive active sites for selectivity O2 chemisorption. Moreover, the high electron enrichment of imidazole as an active site for the 2e− oxygen reduction ensures the rapid reduction of O2. Therefore, the IC−H‐bond enables a total O2 utilization and conversion efficiency of 94.8 % from direct photocatalytic air reduction, achieving a H2O2 production rate of 1518 μmol/g/h that is 16 and 23 times compared to poly‐ionic‐liquid composite without spaced imino groups (PIL‐TiO2) and TiO2, respectively.

Integrating ZnO with fibrous silica zirconia p-n heterojunction for effective photoredox of hexavalent chromium and congo red

The co-occurrence of congo red (CR) and hexavalent chromium (Cr (VI)) has presented a significant challenge to the remediation process. Particularly, the efficient elimination of those toxic dyes and Cr (VI) from wastewater by photocatalysis is still a challenge due to the unsatisfactory photocatalytic efficiency and difficult separation of the photocatalyst. Herein, the current study focused on the simultaneous photocatalytic oxidation of CR and reduced Cr (VI) using zinc oxide supported on the fibrous silica zirconia (ZnO/FSZr) catalysts. The synergistic effect of ZnO and FSZr results in faster charge migration and more efficient separation of photogenerated charge carriers. Remarkably, simultaneous remediation of Cr (VI) and CR over 0.5 g/L of 10ZnO/FSZr showed 78% and 100% photocatalytic efficiency, respectively, under visible light irradiation within 3 hours at pH 3 compared to the individual system. The ZnO impedes the recombination of charge carriers through forming p-n heterojunctions, as confirmed by photoluminescence and Mott-Schottky analysis. Scavenger tests proved that photogenerated electrons were the main species that reduced Cr (VI) into Cr (III). Holes and hydroxyl radicals also played a part in the photooxidation of CR. The p-n heterojunction demonstrated exceptional cyclic stability even after four continuous cycles, a critical attribute for real-world implementations. Additionally, the visible light (VIS)-ZnO/FSZr system's estimated electrical energy per order consumption was calculated to be 215 kWh m-3, and its operational cost utilization of 10.9 USD demonstrated that this process is exceptionally practical and cost-effective in comparison to alternative photocatalytic processes (VIS-FSZr and VIS).

Mechanistic Analysis of Urea Electrooxidation Pathways: Key to Rational Catalyst Design.

Urea electrolysis is an emerging approach to treating urea-enriched wastewater and an attractive alternative anodic process to the oxygen evolution reaction (OER) in electrochemical clean energy conversion and storage technologies (e. g., hydrogen production and CO2 electroreduction). While the thermodynamic potential for urea oxidation to dinitrogen is quite low compared to that of the OER, the catalysts reported to date require high overpotentials that far exceed those for the OER. Consequently, there is much room for improvement and rational catalyst design for the urea oxidation reaction (UOR). At the same time, due to the urea molecule having a more complex structure than water, UOR can lead to the formation of various products beyond the commonly assumed N2 and CO2 . This concept article will critically assess recent efforts of the research community to decipher the formation mechanisms of UOR products focusing on the systematic analysis of the reaction selectivity. This work aims to analyze the current state of the art and identify existing gaps, providing an outlook for the future design of UOR catalysts with superior activity and selectivity by applying the knowledge of the molecular transformation mechanisms.

Design of Sustainable Aluminium-Based Feedstocks for Composite Extrusion Modelling (CEM).

Additive manufacturing (AM) has become one of the most promising manufacturing techniques in recent years due to the geometric design freedom that this technology offers. The main objective of this study is to explore Composite Extrusion Modelling (CEM) with aluminium as an alternative processing route for aluminium alloys. This process allows for working with pellets that are deposited directly, layer by layer. The aim of the technique is to obtain aluminium alloy samples for industrial applications with high precision, without defects, and which are processed in an environmentally friendly manner. For this purpose, an initial and preliminary study using powder injection moulding (PIM), necessary for the production of samples, has been carried out. The first challenge was the design of a sustainable aluminium-based feedstock. The powder injection moulding technique was used as a first approach to optimise the properties of the feedstock through a combination of water-soluble polymer, polyethyleneglycol (PEG), and cellulose acetate butyrate (CAB) wich produces low CO2 emissions. To do this, a microstructural characterisation was carried out and the critical solid loading and rheological properties of the feedstocks were studied. Furthermore, the debinding conditions and sintering parameters were adjusted in order to obtain samples with the required density for the following processes and with high geometrical accuracy. In the same way, the printing parameters were optimised for proper material deposition.

Modelling photoperiod in enhancing hydrogen production from Chlorella vulgaris sp. while bioremediating ammonium and organic pollutants in municipal wastewater

Municipal wastewater is ubiquitously laden with myriad pollutants discharged primarily from a combination of domestic and industrial activities. These heterogeneous pollutants are threating the natural environments when the traditional activated sludge system fails sporadically to reduce the pollutants' toxicities. Besides, the activated sludge system is very energy intensive, bringing conundrums for decarbonization. This research endeavoured to employ Chlorella vulgaris sp. In converting pollutants from municipal wastewater into hydrogen via alternate light and dark fermentative process. The microalgae in attached form onto 1 cm3 of polyurethane foam cubes were adopted in optimizing light intensity and photoperiod during the light exposure duration. The highest hydrogen production was recorded at 52 mL amidst the synergistic light intensity and photoperiod of 200 μmolm−2s−1 and 12:12 h (light:dark h), respectively. At this lighting condition, the removals of chemical oxygen demand (COD) and ammoniacal nitrogen were both achieved at about 80%. The sustainability of microalgal fermentative performances was verified in recyclability study using similar immobilization support material. There were negligible diminishments of hydrogen production as well as both COD and ammoniacal nitrogen removals after five cycles, heralding inconsequential microalgal cells’ washout from the polyurethane support when replacing the municipal wastewater medium at each cycle. The collected dataset was finally modelled into enhanced Monod equation aided by Python software tool of machine learning. The derived model was capable to predict the performances of microalgae to execute the fermentative process in producing hydrogen while subsisting municipal wastewater at arbitrary photoperiod. The enhanced model had a best fitting of R2 of 0.9857 as validated using an independent dataset. Concisely, the outcomes had contributed towards the advancement of municipal wastewater treatment via microalgal fermentative process in producing green hydrogen as a clean energy source to decarbonize the wastewater treatment facilities.

Microwave-assisted extraction and purification of aleuritic acid from seedlac: A fast, eco-friendly and cost-effective single process for enhanced yield and purity

Aleuritic acid is one of the high-value constituents of lac resin, which has a massive demand in the perfumery industry for synthesizing macrocyclic lactones. The commercial aleuritic acid extraction process is lengthy, inefficient, and produces low-quality aleuritic acid, which necessitates repeated purification using toxic chemicals, bleaching agents, organic solvents, and activated carbon to obtain the desired quality aleuritic acid. This study developed a single process for extraction and purification of aleuritic acid involving microwave-assisted hydrolyzing of the seed lac and removing impurities of lac resin through condensation and alkali heat treatment. The novel process has reduced the overall extraction time from 15 days to 1.5–2 days and increases the yield from 35 to 40 % to 85–86 % and purity from 70 to 86 % to > 98 % in a single process without the use of toxic chemicals, bleaching agents, or organic solvents, unlike the commercially available process. HPLC, FT-IR, DSC, and FESEM techniques were employed to characterize and evaluate the quality of the extracted aleuritic acid. The developed process is highly efficient and cost-effective and offers scalable and fast extraction while requiring minimal chemicals, labor, and energy compared to alternative processes. Moreover, it exhibits greater environmental sustainability.

Overpotential on Oxygen-Evolving Platinum and Ni-Fe-Cu Anode for Low-Temperature Molten Fluoride Electrolytes

AbstractTo eliminate climate gas emissions from aluminum electrolysis, modifying a cryolite-based electrolyte partly replacing Na with K reduces liquidus, allowing a process temperature of 800°C. This enables the use of various metallic alloys for oxygen-evolving inert anode technology. This alternative process requires a higher energy efficiency to compensate for an increased reaction voltage, which highlights the importance of evaluating the kinetics and overpotential on oxygen-evolving anodes. This study evaluates anodic overpotentials using steady-state polarization on platinum and three Ni-Fe-Cu-based alloy compositions in a KF-NaF-AlF3-Al2O3(sat.) electrolyte at 800°C. The polarization curve on the platinum anode reveals two linear Tafel regions, while Ni-Fe-Cu anodes exhibit a single Tafel region. Notably, Ni-Fe-Cu anodes treated with high-temperature air oxidation to develop a pre-formed oxide layer exhibit better electrocatalytic activity than untreated anodes of corresponding composition. The kinetic equations, based on a theoretical model for the proposed mechanism of the oxygen evolution reaction, are derived and utilized to simulate overpotential and current, taking into account surface coverage. This model accurately predicts the two experimentally observed Tafel regions on the platinum anode, indicating a two-step charge transfer-controlled mechanism. We illustrate that multiple Tafel slopes can be attributed to the potential-dependent surface coverage of an adsorbate and can be correlated with the particular rate-determining step.