Radical Production Research Articles

Investigating the Effectiveness of 6Mev Electron and Ultrasound Beams with the Use of Iron Oxide Magnetic Nanoparticles Attached to Cisplatin on B16F10 Cells: In-Vitro Study

Melanoma is considered the deadliest skin cancer that can be treated with surgery, radiotherapy, chemotherapy, etc. The use of magnetic iron oxide nanoparticles (IONPs) in order to increase the effectiveness of electron beams and ultrasound beams by increasing the production of free radicals (ROS) and their ability to deliver chemotherapy drugs is under research. Cisplatin is one of the chemotherapy drugs based on platinum, whose ability to deal with melanoma has recently been clarified. In this study, we studied the synthesis of [Formula: see text], [Formula: see text]@L-Aspartic and [Formula: see text]@L-Aspartic@Cisplatin nanoparticles and we managed to determine the characteristics of each of them using TEM, DLS, FTIR, UV–Vis tests; also, MTT and flow cytometry tests were performed for [Formula: see text] and [Formula: see text]@L-Aspartic with the concentrations of 10, 25, 50, 80 and 100 [Formula: see text] g/mL and for [Formula: see text]@L-Aspartic@Cisplatin and cisplatin with concentrations of 0.6, 1.6, 5, 10 and 20 [Formula: see text] g/mL alone and in combination with electron beam with doses of 1 Gy, 2[Formula: see text]Gy and 3[Formula: see text]Gy and ultrasound beam with the intensities of 1[Formula: see text]W/cm2 and 2[Formula: see text]. The results of the mining TEM test show the size of [Formula: see text], [Formula: see text]@L-Aspartic and [Formula: see text]@L-Aspartic@Cisplatin to be 25[Formula: see text]nm, 35[Formula: see text]nm and 42[Formula: see text]nm, and the FTIR and UV–Vis tests also confirmed the nanoparticle coating and drug loading; also, the results of MTT and flow cytometry test showed the effectiveness of [Formula: see text], [Formula: see text]@L-Aspartic and [Formula: see text]@L-Aspartic@Cisplatin in increasing the effectiveness of electron beam and ultrasound beam. The use of nanotechnology together with other treatment methods can shed light on a new way to overcome cancer.

Chaperones vs. oxidative stress in the pathobiology of ischemic stroke.

As many proteins prioritize functionality over constancy of structure, a proteome is the shortest stave in the Liebig's barrel of cell sustainability. In this regard, both prokaryotes and eukaryotes possess abundant machinery supporting the quality of the proteome in healthy and stressful conditions. This machinery, namely chaperones, assists in folding, refolding, and the utilization of client proteins. The functions of chaperones are especially important for brain cells, which are highly sophisticated in terms of structural and functional organization. Molecular chaperones are known to exert beneficial effects in many brain diseases including one of the most threatening and widespread brain pathologies, ischemic stroke. However, whether and how they exert the antioxidant defense in stroke remains unclear. Herein, we discuss the chaperones shown to fight oxidative stress and the mechanisms of their antioxidant action. In ischemic stroke, during intense production of free radicals, molecular chaperones preserve the proteome by interacting with oxidized proteins, regulating imbalanced mitochondrial function, and directly fighting oxidative stress. For instance, cells recruit Hsp60 and Hsp70 to provide proper folding of newly synthesized proteins-these factors are required for early ischemic response and to refold damaged polypeptides. Additionally, Hsp70 upregulates some dedicated antioxidant pathways such as FOXO3 signaling. Small HSPs decrease oxidative stress via attenuation of mitochondrial function through their involvement in the regulation of Nrf- (Hsp22), Akt and Hippo (Hsp27) signaling pathways as well as mitophagy (Hsp27, Hsp22). A similar function has also been proposed for the Sigma-1 receptor, contributing to the regulation of mitochondrial function. Some chaperones can prevent excessive formation of reactive oxygen species whereas Hsp90 is suggested to be responsible for pro-oxidant effects in ischemic stroke. Finally, heat-resistant obscure proteins (Hero) are able to shield client proteins, thus preventing their possible over oxidation.

Triplet Electron Exchange in Carbon Nanodots-assisted Long-persistent near-infrared Chemiluminescence for Oncology Synergistic Imaging and Therapy.

In classical photodynamic therapy, tumor cells are killed by the cytotoxic species via type-I/II photochemical reactions, seriously limited by the external photoexcitation and hypoxia. Herein, the electron transfer mechanism between fluorophores and peroxalate-H2O2 reaction is investigated and the singlet/triplet electron exchange is utilized to achieve long-persistent chemiluminescence imaging and synergistic type-I/II/III photodynamic therapy. As a proof-of-concept, the photosensitizers of carbon nanodots (CDs)-loaded chlorin e6 (CDs-Ce6) are designed and integrated with the peroxalate molecules, and the as-prepare polymer carbon nanodots (p-CDs) exhibit novel tumor microenvironment (TME)-responsive long-persistent near-infrared CL and photochemical reactions, evoking the in vivo imaging and synergistic dynamic therapy in tumor tissue. Mechanistically, the excess reactive oxygen species in TME can trigger the chemically initiated singlet/triplet electron exchange between the hydrophobic CDs-Ce6 and peroxalate-derived 1,2-dioxetanes and thus the excess excited singlet/triplet electron of the CDs-Ce6 can ensure the long-persistent near-infrared CL, type I/II photochemical production of hydroxyl radicals, superoxide radical and singlet oxygen, and type III photochemical damage of maladjusted biomacromolecules, enabling the long-persistent near-infrared biological imaging and enhanced cancer therapy. These results shed a new sight into the energy transfer mechanism in chemiluminescence and pave a new sight into the architecture of multifunctional theragnostic nanoplatforms.

Recent Advances in Photoredox/Chromium dual‐Catalyzed Carbonyl Addition Reactions: A Review

The chromium‐catalysed Nozaki‐Hiyama‐Kishi (NHK) reaction is a very dependable technique for alcohol synthesis and is extensively used in the complete synthesis of natural compounds. The majority of these reactions occur via a reductive‐radical‐polar crossover (RRPCO) mechanism, which is crucial for the transformation of reactive radical intermediates. The production of radicals using photoinduced catalytic reactions is now among the most effective approaches. The photoinduced chromium‐catalysed addition reaction to carbonyl compounds is an effective technique for alcohol synthesis that integrates the benefits of photocatalysis with chromium catalysis. Photocatalysis significantly enhances the diversity of radical production, hence broadening the substrate scope in the chromium‐catalysed NHK reaction. This paper primarily examines the photoredox chromium dual‐catalysed carbonyl addition process for alcohol synthesis, including numerous methods for radical generation.

Mild Magnetothermal Immunotherapy for Malignant Pleural Effusion.

Malignant pleural effusion (MPE) is one of the most difficult complications of cancer to cure, usually indicating poor prognosis in late-stage cancer patients. Due to the presence of a large number of tumor-associated immune cells with the tumor promoting phenotype in MPE and pleural tumors, current clinical therapy offers limited effectiveness. Here, a mild magnetothermal regulation strategy is proposed based on a magnetic nanocatlytic nanoplatform ZCMF@PEG-AF (ZCMF-AF)constructed by surface-modifying anti-F4/80 antibody (AF) on ZnCoFe2O4@ZnMnFe2O4 magnetic nanoparticles (ZCMF) to target and polarize tumor-associated macrophages. Under alternating magnetic field-induced hyperthermia (41-42°C), ZCMF-AF exhibits in situ nanocatalytic production of hydroxyl radicals via released iron ions under acidic cellular environment, which induces repolarization from the immunosuppressed M2 phenotype to the M1 phenotype. More importantly, the tumor cell damage induced by M1 macrophages and magnetic hyperthermia promote the maturation of dendritic cells, which subsequently awakens cytotoxic T lymphocytes to combat tumor cells. The integrated innate and adaptive immunity activations based on ZCMF-AF nano-immunomedicine through intrapleural administration elicit substantially regulated immune microenvironment of MPE and pleural tumors. Moreover, the interpleural magnetic nanoparticle-based immunotherapy effectively reduced the MPE volume and inhibited tumor growth in the pleural cavity, significantly prolonging the survival of the MPE-bearing mice.

Pseudomonas aeruginosa biofilm decontamination and removal by Ar/H2O cold atmospheric plasma in endoscope-like tubing

Abstract In medical device disinfection, removing bacteria and biofilms is challenging due to the poor penetration of detergents into the biofilm matrix. This is specifically true for endoscopes, which cannot be fully sterilized. This paper presents a new technique for decontaminating and removing P. aeruginosa biofilm from endoscope tubing using cold atmospheric plasma (CAP). The CAP is produced everywhere inside a contaminated tube under sustained Ar/H2O flow. The tube arrangement mimics the working channel environment of an endoscope, which is particularly difficult to sterilize. The discharge’s chemical activity was optimized by increasing the voltage without increasing the total power, which enhanced the production of hydroxyl radicals (OH) and hydrogen peroxide (H2O2). The disinfection treatment was tested on 24 h grown biofilm using the crystal violet assay for biofilm removal and the regrowth assay for bacterial decontamination. The treatments demonstrated effective decontamination capabilities at all treatment times with no bacterial regrowth. Etching of the biofilm sample by OH radicals was observed. After 30 min of treatment, only 18 ± 4% of biofilm remained on the surface, indicating near-complete biofilm removal and total absence of bacterial regrowth. This preliminary study demonstrates the effectiveness of using the direct contact of an Ar/H2O plasma to decontaminate and remove biofilm from complex shapes, such as flexible polytetraethylene tubes. It has the potential to enhance and shorten the disinfection of medical equipment, such as endoscopes.

A bioinspired sulfur–Fe–heme nanozyme with selective peroxidase-like activity for enhanced tumor chemotherapy

Iron-based nanozymes, recognized for their biocompatibility and peroxidase-like activities, hold promise as catalysts in tumor therapy. However, their concurrent catalase-like activity undermines therapeutic efficacy by converting hydrogen peroxide in tumor tissues into oxygen, thus diminishing hydroxyl radical production. Addressing this challenge, this study introduces the hemin–cysteine–Fe (HCFe) nanozyme, which exhibits exclusive peroxidase-like activity. Constructed through a supramolecular assembly approach involving Fmoc-l-cysteine, heme, and Fe²⁺ coordination, HCFe distinctly incorporates heme and [Fe–S] within its active center. Sulfur coordination to the central Fe atom of Hemin is crucial in modulating the catalytic preference of the HCFe nanozyme towards peroxidase-like activity. This unique mechanism distinguishes HCFe from other bifunctional iron-based nanozymes, enhancing its catalytic selectivity even beyond that of natural peroxidases. This selective activity allows HCFe to significantly elevate ROS production and exert cytotoxic effects, especially against cisplatin-resistant esophageal squamous cell carcinoma (ESCC) cells and their xenografts in female mice when combined with cisplatin. These findings underscore HCFe’s potential as a crucial component in multimodal cancer therapy, notably in augmenting chemotherapy efficacy.

Bovine Lung Peptides after Trypsinolysis Reveal Anti-Exudative Activity

Abstract Enzymatic hydrolysates of proteins isolated from cow lungs are used as anti-inflammatory agents for the growth and regeneration of new tissues. Hydrolysates were observed to inhibit the production of free radicals in cells and have a high anti-exudative activity even in low doses. In this study, we established the anti-exudative activity of peptides of protein hydrolysates isolated from bovine lungs. The anti-exudative activity of the peptides sum was compared with acetylsalicylic acid (ASA) and prednisolone, and the dynamics of inflammation were studied by tumour formation using carrageenan and formalin. Between 1 h and 24 h after administration of the drug, the effect of the peptides sum showed a significantly better indicator than the rest of the means. In general, the anti-exudative activity of the peptides sum was 2–3 times higher than the rest of the preparations. Biochemical indicators of prednisolone and peptides sum in two doses of 10−6 μg/kg and 10−4 μg/kg were studied. As a result of the study, it was found that the peptides sum at 10−6 μg/kg dose enhanced alanine aminotransferase (ALT) activity by 17.1% compared to those resulting from prednisolone treatment. In C-reactive protein (CRP) and antistreptolysin O (ASO) indicators, 10−4 μg/kg dose showed high activity. The sum of isolated peptides reduced ALT and ASO levels. This study provides additional support for preparing anti-inflammatory means from the peptides sum isolated from bovine lungs.

EVALUATION OF GLUTATHIONE PEROXIDASE ACTIVITY, MALONYLALDEHYDE AND SELENIUM LEVELS IN SICKLE CELL ANAEMIA INDIVIDUALS ATTENDING NAUTH, NNEWI IN SOUTH-EASTERN NIGERIA.

Background: Oxidative stress is an imbalance between the production and clearance of toxic free radicals known as reactive oxygen species (ROS). It is associated with hemolysis, a hallmark of SCD. SCD has long been recognized as an inflammatory condition and oxidative stress play important role in pathophysiology of SCA. Imbalance between production and elimination of reactive oxygen species (ROS) damages cell structures, including lipids, membranes, proteins and nucleic acids resulting in cell death or altered cell function. Aim: The aim of this study was to measure the serum level of Glutathione peroxidase, Malonaldehyde and Selenium in SCA (HbSS) in their steady state, AA (Healthy adult) and AS (sickle cell carriers) Methods: This is a cross- sectional study. A total of one hundred and fifty aged matched participants were recruited for this study.50 SCA subjects with sickle cell anemia (SS). Glutathione peroxidase and Malonyaldehyde were measured using turbidometry and colorimetric methods respectively while Selenium was analysed using Atomic Absorption Spectrophotometry (AAS) Results: The result of analysis of variance (ANOVA) showed that the mean serum level of MDA concentration (2.97±0.29) was higher in the SS group and was statistically significant (p< 0.05). MDA concentration was lower in the AS group. In the post hoc analysis MDA was statistically significant between SS vs AS and AA vs AA. The glutathione peroxidase activity was significantly lower in the SS group (0.85±0.12) compare with the mean values obtained in the AA and AS group. The GPx activity among the three groups was statistically significant while the post hoc analysis among the three groups showed statistical difference and was significant (p < 0.005) The Selenium levels in the SS group is lower compared with the values observed between the AA and AS group. The Se levels in the SS group was statistically lower (5.73±1.34) (p < 0.05) and showed significant difference. The comparison study between AS vs SS and AA vs AA were statistically significant. Conclusion: The decrease in selenium level potentiates low and weakened antioxidant activity and capacity which also is a reflection of low level of glutathione peroxidase observed which is supposed to attack free radicals to prevent oxidative stress. The findings from this study are in tandem with other researches suggesting that the pathophysiology of sickle cell disease is associated with oxidative stress

Activation of Peroxymonosulfate by a Mn0.7Co0.5O2@C Catalyst for the Degradation of Tetracycline

AbstractPersulfate advanced oxidation technologyshows great potential in the removal of organic pollutants. Inthis study, a Mn0.7Co0.5O2@C catalyst wassynthesized from MnCO3‐ZIF‐67 precursor via calcination and employedto activate peroxymonosulfate (PMS) for the degradation of tetracycline (TC).The catalyst, characterized by a plethora of active sites and superior electrontransfer capabilities, mitigated the sluggish reaction kinetics associated withweak electron transfer. Degradation experiments demonstrated an 87.54% removalefficiency within 60 minutes using 10 mg of catalyst, outperforming PMS aloneby 2.3‐fold. The Mn0.7Co0.5O2@C/PMS system'ssynergistic effects and mechanisms were elucidated, with experiments confirmingthe generation of reactive species including singlet oxygen (1O2), sulfate radicals (SO4•−), and hydroxyl radicals (•OH).The catalyst's exceptional performance is attributed to the valence cycling ofMn and Co ions, facilitating PMS activation and the production of radicals. Additionally, the lattice oxygen within the catalyst is oxidized to form reactive oxygenspecies, which, in conjunction with oxygen vacancies, react with PMS to producenon‐radical species (1O2). The synergistic oxidationeffects of these free radicals and non‐radicals ultimately facilitate theremoval of TC, offering a novel approach for the treatment of organicwastewater with persulfate‐based advanced oxidation processes.

Exploring Neuroprotection against Radiation-Induced Brain Injury: A Review of Key Compounds.

Brain radiation is a crucial tool in neuro-oncology for enhancing local tumor control, but it can lead to mild-to-profound and progressive impairments in cognitive function. Radiation-induced brain injury is a significant adverse effect of radiotherapy for cranioencephalic tumors, primarily caused by indirect cellular damage through the formation of free radicals. This results in late neurotoxicity manifesting as cognitive impairment due to free radical production. The aim of this review is to highlight the role of different substances, such as drugs used in the clinical setting and antioxidants such as ascorbate, in reducing the neurotoxicity associated with radiation-induced brain injury. Currently, there is mainly preclinical and clinical evidence supporting the benefit of these interventions, representing a cost-effective and straightforward neuroprotective strategy.

Exploring the photocatalytic performance of (CH3NH3)2AgInBr6, a Pb-free perovskite, and the composite with a MgAlTi layered double hydroxide for air purification purposes

Pb-free metal halide perovskites (MHPs) have lately been employed in different types of photocatalytic applications due to their high absorption in the visible region and excellent electrochemical properties. In this work, the In-based (CH3NH3)2AgInBr6 (MAIB) perovskite has been synthesized using a solvent-free mechanochemical method and the photocatalytic activity has been assessed in the NO removal reaction. The ball milling approach has been employed to obtain microcrystals with a high degree of crystallinity. The diffuse reflectance spectroscopy reveals a band gap energy of 3.44 eV but with an absorption tail covering the visible region. The photocatalytic experiments reveal a high NO abatement of 92 % and 32 % under UV-Vis and visible irradiation, respectively. The cyclability of the MAIB material was investigated during six cycles obtaining an almost nearly constant performance. In a novel approach, the low selectivity showed by the MAIB perovskite in the DeNOx process was circumvented by the preparation of a composite with the MgAlTi layered double hydroxide (LDH). The presence of MgAlTi-LDH avoids the release of NO2 during the photochemical oxidation of the NO gas. Under visible light, the MAIB perovskite is the active species leading to the production of superoxide radicals, which initiate the photochemical process. The MAIB/LDH composite exhibited good efficiency and outstanding selectivity to remove NO gas, together with long-term stability when irradiated under visible light.

Salicylic acid mitigates chilling injury to peaches by improving antioxidant capacity and energy metabolism

Previous study reported positive impact of salicylic acid on other fruits; therefore, this study aimed to determine whether it can boost the antioxidant capacity and regulate energy metabolism in peach fruit against chilling injury during cold storage Peaches were soaked in different concentrations (0, 1, 2, 3, and 4 mmol L-1) of salicylic acid for 5 min and then stored at (4 ± 1) °C for 32 d The results demonstrated that 2 mmol L-1 salicylic acid treatment inhibited the development of chilling injury, maintained fruit's firmness, reduced the rate of superoxide anion radical production, H2O2 and malondialdehyde content, and maintained high total phenolics and total flavonoid contents. Moreover, it increased the viability of phenylalanine ammonia-lyase, peroxidase, catalase, and superoxide dismutase and inhibited polyphenol oxidase activity. Salicylic acid treatment also maintained higher glutathione and ascorbic acid content and increased ascorbate peroxidase, glutathione, monodehydroascorbate, and dehydroascorbate reductase viability. Salicylic acid treatment additionally delayed the decline in the contents of adenosine triphosphate, adenosine diphosphate, and energy charge. It increased the activities of cytochrome oxidase, succinate dehydrogenase, and hydrogen and calcium ion ATPase. Salicylic acid treatment, therefore, enhanced the chilling resistance of peaches by modulating antioxidant-related substances and energy metabolism.

The Therapeutic Effects of SP-8356, a Verbenone Derivative, with Multimodal Cytoprotective Mechanisms in an Ischemic Stroke Rat Model.

An ischemic cerebral stroke results from the interruption of blood flow to the brain, triggering rapid and complex cascades of excitotoxicity, oxidative stress, and inflammation. Current reperfusion therapies, including intravenous thrombolysis and mechanical thrombectomy, cause further brain injury due to reperfusion-induced cytotoxicity. To date, novel cytoprotective therapies that could address these challenges have yet to be developed, likely due to the limitations of targeting a single pathologic mechanism. To address these unmet clinical needs, we investigated a synthetic verbenone derivative, SP-8356, as a potential multi-target cytoprotective agent for acute ischemic strokes. In transient middle cerebral artery occlusion (MCAO) rats, SP-8356 significantly reduced brain infarct and edema volumes while improving acute neurological deficits in a dose-dependent manner. Furthermore, SP-8356 improved long-term outcomes, particularly by reducing mortality. These potent cytoprotective effects of SP-8356 were achieved by suppressing the excessive production of free radicals and pro-inflammatory cytokines, reducing the infiltration of inflammatory cells, and mitigating increases in blood-brain barrier permeability. Additional research is needed to determine whether co-administration of SP-8356 can extend the therapeutic time window of reperfusion therapies by mitigating ischemia/reperfusion injury.

Theoretical Insight into Antioxidant Mechanism of Caffeic Acid Against Hydroperoxyl Radicals in Aqueous Medium at Different pH-Thermodynamic and Kinetic Aspects.

In this study, the DFT/M062X/PCM method was applied to investigate thermodynamic and kinetic aspects of reactions involved in possible mechanisms of antioxidant activity of caffeic acid against HOO● radicals in aqueous medium at different pH values. Kinetic parameters of the reactions involved in HAT (Hydrogen Atom Transfer), RAF (Radical Adduct Formation), and SET (Single Electron Transfer) mechanisms, including reaction energy barriers and bimolecular rate constants, were determined, and identification and characterization of stationary points along the reaction pathways within HAT and RAF mechanisms were performed. Inspection of geometrical parameters and spin densities of the radical products formed within HAT and RAF mechanisms revealed that they are stabilized by hydrogen bonding interactions and the odd electron originated through the reaction with the HOO● radical is spread over the entire molecule, resulting in significant radical stabilization. Thermodynamic and kinetic data collected in this study indicated that increasing pH of the medium boosts the antioxidant activity of caffeic acid by reducing the energy required to generate radicals within the RAF and/or HAT mechanism and, at extremely high pH, where the trianionic form of caffeic acid is a dominant species, by the occurrence of an additional fast, diffusion-limited electron-related channel.

Crystal facet regulation enhances the photocatalytic performance for gaseous toluene degradation in BiOCl by promoting the activation of the methyl C(sp3)-H bond

In the field of heterogeneous photocatalysis, the exposure and arrangement of surface atoms exert a profound impact on the reactivity of photocatalysts, dictating the formation of various active sites and reaction pathways. Utilizing crystal facet engineering and surface modification under standard temperature and pressure conditions, we have synthesized BiOCl photocatalysts with an increased exposure of (110) facets, denoted as oxygen vacancy (Ov). The coordination of Bi3+ with thiourea and acetic acid governed the growth direction of BiOCl, inducing lattice distortion andin synergy with ethylene glycol (EG), promoting the preferential formation of Ov. This innovative strategy not only fine-tuned the bandgap of BiOCl by adjusting the conduction band (CB) position but also significantly augmented the migration velocity and separation efficiency of surface charge carriers. In the photocatalytic interaction with toluene, BiOCl demonstrated an enhanced adsorption capacity and a more potent activation of methyl C (sp3)-H bonds, concomitant with the production of substantial superoxide anion radicals (·O2–), which expedited the degradation of toluene. Theoretical computations and detailed characterizations have unveiled the corresponding mechanism and the degradation pathways of toluene at the photocatalytic interface.

Sulfasalazine-loaded nanoframes: A new frontier in bladder cancer therapy through ferroptosis induction

Promoting ferroptosis in tumor cells has emerged as a promising strategy for cancer therapy. Nonetheless, the heightened antioxidant activity within tumor cells hampers this approach, diminishing its effectiveness and fostering drug resistance. In this study, a new type of sulfasalazine (SAS) loaded nanoframe self-etched Pt-Co nanodendrites (Pt/Co-BNN@SAS) was developed, presenting a novel avenue for inducing ferroptosis in tumor cells by depleting glutathione (GSH) for cancer treatment. Pt/Co-BNN exhibits notable peroxidase (POD) activity, catalyzing the production of abundant oxygen radicals through the consumption of hydrogen peroxide (H2O2) and the concurrent depletion of GSH. Simultaneously, the liberated sulfasalazine (SAS) from Pt/Co-BNN@SAS effectively obstructs system xc-, impeding the absorption of cystine by tumor cells and thereby expediting GSH depletion. The expeditious reduction of GSH markedly stimulates the accumulation of lipid peroxides (LPO) and suppresses glutathione peroxidase 4 (GPX4), consequently triggering ferroptosis in bladder cancer cells and inhibiting the migration ability of bladder cancer cells effectively. This research contributes to a more profound comprehension of nano-drug-biological interactions and provides a prospective outlook on treating bladder cancer by instigating ferroptosis in tumor cells through GSH depletion.

Time and Potential-Resolved Studies of Bipolar Plate Corrosion for Polymer Electrolyte Membrane Fuel Cells

Stainless steels are regarded as the reference materials for metal bipolar plates for polymer electrolyte membrane fuel cells (PEMFCs) due to their low cost and weight, high electrical conductivity, flexural strength, ease of machining, and ability to be formed into thin sheets. The main drawback is their susceptibility to corrosion in typical acidic, oxidizing environments of PEMFCs, 1,2,3 which can degrade the performance of the plate and other components of the PEMFC. The simultaneous presence of iron ions released by corrosion of the BPP and hydrogen peroxide is responsible for hydroxyl radical production, resulting in degradation of the membrane and cathode catalyst layer ionomer.4 Applying a protective coating to the metal bipolar plates is an effective way to improve its corrosion resistance.5 This work investigates corrosion rates of SS316L bipolar plates on the basis of the measured concentrations of cations (e.g., Fe, Cr, and Ni) in an aqueous electrolyte as a function of applied potential and corrosion environment.Techniques employing electrochemical flow cells (EFC) directly coupled to an inductively-coupled plasma mass spectrometer (ICP-MS) allow for more precise time- and potential-resolved detection of dissolved species. This work will report real-time data on leaching of Fe, Cr, and Ni from SS316L substrates subjected to potential cycles using a flow-through electrochemical cell coupled with an on-line ICP-MS instrument, with sub-part per billion (ppb or μg/L) sensitivity, providing the ability to resolve dissolution during potential scans. The results of this work provide a baseline for studying the efficacy of stainless steel bipolar plate coatings in mitigating degradation of PEMFCs. References Leng, P. Ming, D. Yang, C. Zhang. J. of Power Sources 451, (2020) 227783.Kumagai, S.-T. Myung, T. Ichikawa, H. Yashiro, Y. Katada, J. Power Sources 202 (2012) 92.D. Papadias, R. K. Ahluwalia, J. K. Thomson, H. M. Meyer III, M. P. Brady, H. Wang, J. A. Turner, R. Mukundan, R. Borup. J. of Power Sources 273 (2015) 1237.Elferjani, G. Serre, B. Ter-Ovanessian, B. Normand. International Journal of Hydrogen Energy 46, (2021), 32226-32241.Liu, Q. Jia, B. Zhang, Z. Lai, L. Chen. International Journal of Hydrogen Energy 47, (2022) 22915. Acknowledgements This research is supported by the U.S. Department of Energy, Energy Efficiency and Renewable Energy, Hydrogen and Fuel Cell Technologies Office under the auspices of the M2FCT consortium. Argonne National Laboratory is managed for the U.S Department of Energy by the University of Chicago Argonne, LLC under contract DE-AC-02-06CH11357.

Occurrences of per- and Polyfluoroalkyl Substances (PFAS) in the Environment and Their Oxidative Degradation By Modified Fenton Treatment

Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This research examines the remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also evaluated, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants. Per- and polyfluoroalkyl substances (PFAS) are a class of synthetic chemicals that have become ubiquitous environmental contaminants due to their widespread use and extreme persistence. This literature review examines the occurrence, health impacts, regulation, and remediation of PFAS, with a focus on oxidative degradation methods. PFAS are characterized by strong carbon-fluorine bonds that make them highly stable and resistant to degradation. They bioaccumulate in living organisms and have been linked to various adverse health effects, including liver damage, thyroid disruption, and developmental issues. Remediation approaches include adsorption, filtration, and advanced oxidation processes (AOPs). Fenton-based AOPs for PFAS degradation, particularly anodic Fenton treatment (AFT) and photo-assisted AFT (P-AAFT). AFT uses electrochemistry to generate hydroxyl radicals and regenerate ferrous ions, addressing limitations of classic Fenton treatment. P-AAFT incorporates UV irradiation to enhance radical production and PFAS degradation efficiency. Kinetic modeling of PFAS degradation is also discussed, highlighting the importance of understanding reaction mechanisms and rates. The research seeks to advance understanding of PFAS degradation kinetics and mechanisms, potentially informing more effective remediation strategies for these persistent environmental contaminants.

(Invited) Advancing and Manufacturing Materials for Next Generation Li-Ion Batteries

As conventional intercalation-type Li-ion battery electrode materials approach their theoretical limits, substantial gains in battery energy density only come as a trade-off in safety or performance. Supply chain limitations additionally constrain the use of many conventional materials. This talk will discuss how novel, industry-relevant active and inactive materials may significantly improve performance, reduce the cost of Li-ion batteries, overcome existing and expected supply chain challenges and pave the way for renewable energy technologies. For example, Sila's innovative drop-in-replacement nanocomposite silicon anode powder offers 6 times higher gravimetric capacity than graphite, permits both fast charging and over 20% more energy density today over state-of-the-art lithium-ion, and enables radical product innovation - all without compromising performance. This material has been shipping in millions of devices for three years and is scaling up for massive electric vehicle (EV) use by mid-decade. With Sila’s industrialized and scaled scientific innovation, wearables, portable electronics, and EV manufacturers can create breakthrough products today that will minimize our environmental impact tomorrow. This talk will provide multiple examples of flexible ceramic separators and other technologies that may become instrumental for the transition to a clean and energy-sustainable economy.