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Iron redox flow batteries (Fe‐RFBs) hold significant promise for achieving cost‐effectiveness and utilizing abundant materials for stationary energy storage applications. Here, a design of a novel Fe complex utilizing a nitrogenous phosphonate/carboxylate mixed ligand, N,N‐Bis(phosphonomethyl)glycine (BMPG), is presented to achieve high performance Fe anolyte. Compared to its all‐phosphonate form, nitrilotri(methylphosphonic acid) (NTMPA), the new complex Fe(BPMG)2 demonstrates a negatively shifted redox potential, resulting in ≈0.07 V (≈10%) increase in battery output voltage. Full battery testing paired with ferrocyanide catholyte demonstrates stable cycling (capacity degradation <0.0001%/cycle) over 730 consecutive charge/discharge cycles with Coulombic Efficiency of 100% at a current density of 20 mA cm−2 under near neutral pH (≈8). Of particular interest, density functional theory (DFT) studies and operando Raman measurements provide strong evidence supporting a molecular structure in BPMG, which reveals the mixed phosphonate/carboxylate groups in BPMG maintain the octahedral coordination of the Fe ion center with phosphonates exclusively, while leaving the carboxylate unbound for both Fe(II) and Fe(III) complexes. This structural similarity between BPMG‐based Fe(II) and Fe(III) complexes effectively mitigates the slow redox reaction kinetics observed in Fe(NTMPA)2 anolyte, where significant ligand reorientation occurs between Fe(II) and Fe(III) complexes. [ABSTRACT FROM AUTHOR]

The contamination of aquatic environments by organic dye contaminants in industrial wastewater has attracted widespread global attention. The heterogeneous Fenton-like process presents an attractive method for degrading dye pollutants, especially when such reactions are conducted under neutral pH. In this study, Fe2O3/MnO2 composite was employed as a novel heterogeneous catalyst for activating hydrogen peroxide (H2O2) to oxidize and subsequently degrade methylene blue (MB) under neutral pH. Multiple characterization results have confirmed the presence of MnO2 and Fe2O3 as the primary phases of the synthesized compound catalyst. Degradation experiments have demonstrated that the degradation efficiency of MB approaches 100% under the conditions of H2O2 concentration of 0.30% and Fe2O3/MnO2 amount of 0.888 g/L. Furthermore, the Fe2O3/MnO2 catalyst exhibits consistent and outstanding catalytic activity within a broad pH range from 5 to 9 benefiting from the strong interface interaction in Fe2O3/MnO2. The investigation into the kinetics of the Fenton-like reaction indicates that the catalytic degradation of MB by Fe2O3/MnO2 in conjunction with H2O2 follows pseudo-first-order kinetics. Moreover, supplementary scavenging experiments have demonstrated the crucial role played by hydroxyl radicals (·OH) in the catalytic oxidation mechanism of MB. This study offers a promising catalyst for the treatment of dye-containing wastewater under neutral pH condition.

This experimental study aimed to evaluate the effectiveness of NSOS (Neutral-pH superoxidized solution) with peritoneal lavage in rat fecal peritonitis models. Forty Wistar rats weighing between 250-300 g were used for the study. All rats were inducted for fecal peritonitis formation. The rats were divided into five groups as follows; Group 0: control, no intervention. Group 1: Application of 10 mg/kg NSOS into the peritoneal cavity after 6 h of induction of peritonitis. Group 2: 10 mg/kg NSOS application and repeated at 24 and 48 h. Group 3: NSOS + Antibiotic treatment (Seftriakson 30 mg/kg/day IM 2x1 + metronidazol 15 mg/kg/day IM 2x1). Group 4: Only antibiotic treatment (Seftriakson 30 mg/kg/day IM 2x1 + metronidazol 15 mg/kg/day IM 2x1). The animals were examined for peritoneal and thoracal abscess formation, adherences, and any abnormality with inspection after sacrificing on the 7th day. The peritoneal lavage fluid culture for microbiological analysis and blood samples were taken for blood cultures, biochemical and infectious parameters of WBC, CRP, TNF-a, IL-6, IL-1 ß, and IL-10. Peritonitis was developed in all rats at the end of follow-up. No death was observed in rats on the seventh day of the experiment. Group 3 (NSOS + Antibiotic treatment) showed the most significant improvement in the infection of peritoneal fluid. NSOS and antibiotic together (Group 3) were found to be more effective against Klebsiella than Enterococcus sp. The blood cultures showed a significant reduction in all groups. The infectious parameters including IL-6, IL-1 ß, and IL-10 showed no significant difference in the first week of treatment between all groups. Only TNF-a was observed significantly lower in group 3 when compared to the other groups (P=0.001). Peritoneal lavage with neutral pH-superoxidized water plus an antibiotic regimen is the most effective treatment in the rat fecal peritonitis model. Further studies including human subjects are needed to investigate its effectiveness and validity. [ABSTRACT FROM AUTHOR]

This experimental study aimed to evaluate the effectiveness of NSOS (Neutral-pH superoxidized solution) with peritoneal lavage in rat fecal peritonitis models. Forty Wistar rats weighing between 250-300 g were used for the study. All rats were inducted for fecal peritonitis formation. The rats were divided into five groups as follows; Group 0: control, no intervention. Group 1: Application of 10 mg/kg NSOS into the peritoneal cavity after 6 h of induction of peritonitis. Group 2: 10 mg/kg NSOS application and repeated at 24 and 48 h. Group 3: NSOS + Antibiotic treatment (Seftriakson 30 mg/kg/ day IM 2x1 + metronidazol 15 mg/kg/day IM 2x1). Group 4: Only antibiotic treatment (Seftriakson 30 mg/kg/day IM 2x1 + metronidazol 15 mg/kg/day IM 2x1). The animals were examined for peritoneal and thoracal abscess formation, adherences, and any abnormality with inspection after sacrificing on the 7th day. The peritoneal lavage fluid culture for microbiological analysis and blood samples were taken for blood cultures, biochemical and infectious parameters of WBC, CRP, TNF- α, IL-6, IL-1 β, and IL-10. Peritonitis was developed in all rats at the end of follow-up. No death was observed in rats on the seventh day of the experiment. Group 3 (NSOS + Antibiotic treatment) showed the most significant improvement in the infection of peritoneal fluid. NSOS and antibiotic together (Group 3) were found to be more effective against Klebsiella than Enterococcus sp. The blood cultures showed a significant reduction in all groups. The infectious parameters including IL-6, IL-1 β, and IL-10 showed no significant difference in the first week of treatment between all groups. Only TNF- α was observed significantly lower in group 3 when compared to the other groups (P=0.001). Peritoneal lavage with neutral pH-superoxidized water plus an antibiotic regimen is the most effective treatment in the rat fecal peritonitis model. Further studies including human subjects are needed to investigate its effectiveness and validity.

Cobalt‐based oxides have attracted attention as active electrocatalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. However, highly OER active catalysts at near‐neutral pHs are also desired for practical applications. Herein, a dry phosphate functionalization process is presented to enhance the OER activity of different cobalt‐based catalysts at near‐neutral pHs. Electrochemical evaluations show that the P‐functionalization can effectively improve the OER activity at near‐neutral pHs for La0.2Sr0.8CoO3–δ, La0.2Sr0.8Co0.8Fe0.2O3–δ, and CoOx catalysts, but not for La0.5Sr1.5CoO4–δ. Bulk and surface sensitive X‐ray absorption spectroscopy and X‐ray photoelectron spectroscopy unveil the influence of P incorporated in the order of ppm on the electronic state, local structure, and surface composition of the investigated catalysts. The P‐functionalization reduces the Co oxidation state in La0.2Sr0.8CoO3–δ and La0.5Sr1.5CoO4–δ, but the latter also presents significant Sr‐based segregations on the surface‐inhibiting OER activity at near‐neutral pHs. Differently, La0.2Sr0.8CoO3–δ, and to a lesser extent La0.2Sr0.8Co0.8Fe0.2O3–δ and CoOx, shows improved OER activity at neutral pH after the P‐functionalization. The findings disclose that P‐functionalization successfully enhances OER activity at near‐neutral pHs and that both phosphate ion assistance in the OER mechanism and catalyst Co oxidation state can play a role in the enhanced OER activity. [ABSTRACT FROM AUTHOR]

Cobalt‐based oxides have attracted attention as active electrocatalysts for the oxygen evolution reaction (OER) in alkaline electrolytes. However, highly OER active catalysts at near‐neutral pHs are also desired for practical applications. Herein, a dry phosphate functionalization process is presented to enhance the OER activity of different cobalt‐based catalysts at near‐neutral pHs. Electrochemical evaluations show that the P‐functionalization can effectively improve the OER activity at near‐neutral pHs for La0.2Sr0.8CoO3–δ , La0.2Sr0.8Co0.8Fe0.2O3–δ , and CoO x catalysts, but not for La0.5Sr1.5CoO4–δ . Bulk and surface sensitive X‐ray absorption spectroscopy and X‐ray photoelectron spectroscopy unveil the influence of P incorporated in the order of ppm on the electronic state, local structure, and surface composition of the investigated catalysts. The P‐functionalization reduces the Co oxidation state in La0.2Sr0.8CoO3–δ and La0.5Sr1.5CoO4–δ , but the latter also presents significant Sr‐based segregations on the surface‐inhibiting OER activity at near‐neutral pHs. Differently, La0.2Sr0.8CoO3–δ , and to a lesser extent La0.2Sr0.8Co0.8Fe0.2O3–δ and CoO x , shows improved OER activity at neutral pH after the P‐functionalization. The findings disclose that P‐functionalization successfully enhances OER activity at near‐neutral pHs and that both phosphate ion assistance in the OER mechanism and catalyst Co oxidation state can play a role in the enhanced OER activity.

Neutral pH PVA/glycerol/Na2SO4 hydrogels were made by aging at room temperature, the effect of Na2SO4 concentration was evaluated, and the hydrogel with the best properties was tested as a neutral pH polymeric hydrogel electrolyte in a supercapacitor device with activated carbon electrodes. PVA/glycerol/Na2SO4 hydrogels were chemically and structurally studied using Fourier transform infrared spectroscopy, Raman spectroscopy, and X-ray diffraction. Hydrogel with 0.40 mol L−1 of Na2SO4 has the most presence of hydrogen bonds and a lesser presence of crystalline regions in its polymeric matrix. By impedance spectroscopy, the ionic conductivity of the hydrogels was calculated. Hydrogel with 0.40 mol L−1 of Na2SO4 has the highest value of ionic conductivity 17.4 mS cm−1. This hydrogel was used as a polymer hydrogel electrolyte in a supercapacitor with Printex XE2B activated carbon electrodes by cyclic voltammetry and galvanostatic charge/discharge cycles. The supercapacitor device with 0.40 mol L−1 Na2SO4 hydrogel reached a working potential window of 2.0 V in the cyclic voltammograms. Charge/discharge plots of the supercapacitor device with 0.40 mol L−1 Na2SO4 hydrogel exhibit a triangle behavior at different current densities. Supercapacitor device with 0.40 mol L−1 Na2SO4 hydrogel presents an equivalent series resistance of 14.7 ohms cm−2, a specific capacitance of 54.7 F g−1, and a specific energy of 7.6 Wh kg−1 at 0.5 A g−1. Obtained results were compared with a supercapacitor device with Na2SO4 1.0 mol L−1 and previously works. [ABSTRACT FROM AUTHOR]

Among various chalcogenide materials, transition metal sulfides are known to be effective catalysts for the electrochemical hydrogen evolution reaction (HER). In particular, Ni-Co-S is a promising material for the next generation of non-precious metal HER catalysts due to its excellent HER activity in neutral pH solutions. Ni-Co-S is also advantageous in large-scale applications, as it enables relatively simple catalytic synthesis through electrodeposition. In this study, we employed a new S precursor, 2,5-dimercapto-1,3,4-thiadiazole (DMTD), for the electrodeposition of Ni-Co-S, instead of the conventional S precursor, thiourea (TU). Ni-Co-S synthesized with DMTD (Ni-Co-SDMTD) showed enhanced HER activity at neutral pH compared to that synthesized with TU (Ni-Co-STU). It has been found that this improvement in activity is due to the large surface area and high S content of Ni-Co-SDMTD. The S content and HER activity of Ni-Co-SDMTD depend on the concentration of DMTD. At the optimal DMTD concentration (12 mM), Ni-Co-SDMTD exhibited an overpotential of 303 mV at a current density of 10 mA cm− 2 and a Tafel slope of 99 mV dec− 1 in a phosphate buffer solution (pH 7.4). [ABSTRACT FROM AUTHOR]

This study examines the removal efficiency of Tramadol hydrochloride (TR) and mineralization (chemical oxygen demand, COD) by the effective photoinduced Fenton-simulated system under artificial light (UVA). The Box-Behnken design was used to optimize the value of each parameter. The model yielded the following optimal parameters: [TR]0 = 10 mg, ratio ([Oxalate ]0/[Fe3+]0) = 100, initial pH = 2.83, and [Fe3 +]0 = 1.298 mg with effective TR removal (100%) and COD removal efficiency (72.82%). The presence of oxygen has a positive effect by increasing hydrogen peroxide production from 4.36 to 8.12 mg L−1 and by maximizing a change in Fe3+ speciation. The degradation kinetics of ΤR in the oxygen-saturated medium is four times faster than that in the normal aerated medium. The Kapp rate constants increased quickly from 5.72 × 10−2 to 20 × 10−2min−1. The percent COD removal increased to 87.46%, and the final pH increased from 5.31 to 6.23. HIGHLIGHTS The photoinduced Fenton-simulated system was easy to achieve sustainable treatment for Tramadol.; The degradation and mineralization were modeled and optimized using the response surface methodology.; Photo-Fenton-like process with unadjusted initial and final pH.; The effect of oxygen on degradation kinetics, mineralization, final pH and H2O2 production.;

Background: As a class of promising bone augmentation materials, bone cements have attracted particular attention. Due to various limitations, the current bone cements are still imperfect. In this study, an injectable pH neutral bioactive bone cement (PSC/CSC) was developed by mixing phosphosilicate bioactive glass (PSC) and α-calcium sulfate hemihydrate (CSH), with the goal of optimizing bone defects repairs. Methods: A range of compositions (PSC/CSC: 10P/90C, 30P/70C, 50P/50C) were developed and their physicochemical properties evaluated. Their bone regeneration ability was compared to those of two widely used bone cements as controls (calcium phosphate cement (CPC) and Genex®) in rabbit femoral condyle bone defect models for 4, 8 and 12 weeks. Based on physicochemical properties and in vivo bone regeneration ability, the PSC/CSC exhibited the best outcomes was selected. Then, in vitro, the effects of selected PSC/CSC, CPC and Genex® extracts on MC3T3-E1 cell proliferation, migration and osteogenesis as well as angiogenesis of HUVECs were examined. Results: Based on physicochemical properties, the 30P/70C formula exhibited suitable operability and compressive strength (3.5 ± 0.3 MPa), which fulfilled the requirements for cancellous bone substitutes. In vivo, findings from micro-CT and histological analyses showed that the 30P/70C formula better promoted bone regeneration, compared to 10P/90C, 50P/50C, CPC and Genex®. Hence, 30P/70C was selected as the ideal PSC-based cement. In vitro, the 30P/70C extracts showed better promotion of cell viability, alkaline phosphatase (ALP) activity, calcium mineral deposition, mRNA and protein expression levels of osteogenesis in MC3T3-E1 cells, further supporting its superiority. Meanwhile, the 30P/70C extracts also showed better stimulation of HUVECs proliferation and angiogenesis. Conclusion: The new composite cement, 30P/70C, is a favorable bioactive glass-based bone cement with suitable operability, compressive strength and bone regeneration ability. The translational potential of this article: Clinically, treatment of large bone defects is still a major challenge for orthopaedic trauma. We showed that 30P/70C has the potential to be clinically used as an injectable cement for rapid bone repairs and reconstruction of critical sized bone defects.

Plasma‐activated water (PAW) is emerging as a green alternative technology in biomedicine due to its rich and diverse aqueous reactive nitrogen and oxygen species (RONS). This study explores how to configure a pin to water (P2W) discharge to generate neutral pH high‐strength plasma‐activated water (hs‐PAW) and its bactericidal activity on hypervirulent multidrug resistance (MDR) pathogens. The factors affecting the strength of PAW, namely: water type, PAW temperature, plasma enclosure, and activation time, were studied and optimized to generate hs‐PAW having 650 ± 40 mg/l of NO2− ${\mathrm{NO}}_{2}^{-}$ and 215 ± 15 mg/l of H2O2 at a pH of 7. This study demonstrates a simple P2W discharge set up to handle the MDR pathogens and can be easily scalable for real‐world medical applications. [ABSTRACT FROM AUTHOR]

A series of novel MnxFey@SiO2 (x,y = 1–20%) nanocomposites were synthesized for the first time via the sol-gel/combustion method with different content of precursors (Mn and Fe acetate salts). The effect of precursor content and ratio on physicochemical properties were observed by various characterization methods. Moreover, Rhodamine B (RhB) was chosen as the target pollutant to test the performance of these nanocomposites under a photocatalytic Fenton-like reaction. The results showed that the nanocomposite morphology improved by increasing Fe and Mn content. In this study, interesting behavior was observed in BET results which were different from the fact that increasing metal content can decrease the surface area. This study revealed that one metal could be more critical in controlling the properties than another. Moreover, the precursor ratio appears to have a more tangible effect on the surface area than the effect of precursor content. Among all synthesized nanocomposites, Mn1Fe5@SiO2 showed the highest surface area of 654.95 m2/g. At optimum batch conditions (temp = 25 °C, catalyst dosage = 1 g L−1, H2O2 = 75 mmolL−1, and initial RhB concentration = 50 mg L−1), complete removal (simultaneous adsorption/degradation) occurred using Mn1Fe5@SiO2 at neutral pH. This study showed that the designed nanomaterial could be used as a dual functional adsorbent/photocatalyst in different environmental applications. [ABSTRACT FROM AUTHOR]

Enzyme catalytic cascade reactions based on peroxidase nanozymes and natural enzymes have aroused extensive attention in analytical fields. However, a majority of peroxidase nanozymes perform well only in acidic environments, resulting in their optimal pH mismatch with a neutral pH of natural enzymes, further restricting their application in biochemical sensing. Herein, Mn-doped CeO 2 (Mn/CeO 2) performing enhanced peroxidase-like activity at neutral conditions was prepared via a facile and feasible strategy. An effective enzyme cascade catalysis system via integrating glucose oxidase (GOx) with Mn/CeO 2 was developed for one-pot detection of glucose in serum at neutral conditions. Using one-pot multistep catalytic reactions, this work provided a detection platform that allows for faster detection and easier operations than traditional methods. Under optimized conditions, our assay performed a sensitive detection of glucose ranging from 2.0 μΜ to 300 μΜ and a low detection limit of 0.279 μΜ. Notably, favorable analytical outcomes for glucose detection in serum samples were obtained, exhibiting potential applications in clinical diagnosis. [Display omitted] • Mn/CeO 2 with good peroxidase-like activity at neutral pH was prepared. • An effective enzyme cascade catalysis system based on GOx and Mn/CeO 2 was developed. • This method performed a sensitive detection of glucose in serum at neutral conditions. • This method displayed fast detection speed, simple operation, and good accuracy. [ABSTRACT FROM AUTHOR]

α-Fe 2 O 3 catalysts show great potential in heterogeneous catalytic ozonation, but they require rigorous reaction conditions, including a pH of 3 and an ozone concentration above 10 mg/L. Four composite catalysts (ZnO/Fe 2 O 3 , MgCO 3 /Fe 2 O 3 , CuO/Fe 2 O 3 , and Mn 2 O 3 /Fe 2 O 3) were synthesized using hydrothermal methods. Under mild conditions (pH 6.8, [O 3 ] = 30 μg/L), CuO/Fe 2 O 3 , and Mn 2 O 3 /Fe 2 O 3 exhibited degradation efficiencies above 99.7% with low toxicity of intermediate products during the degradation of sulfamethoxazole. The Mn 2 O 3 /Fe 2 O 3 catalyst, through the incorporation of multivalent metal oxides, enhanced Fe2+ reduction, leading to the generation of ·OH, ∙O 2 − and 1O 2. This resulted in a 100% degradation rate and 82% mineralization rate of SMX, demonstrating superior catalytic efficiency. In conclusion, we propose a simple strategy to enhance α-Fe 2 O 3 catalytic efficiency under mild conditions using composite multivalent transition metal oxides. [Display omitted] • ZnO, MgCO 3 , CuO and Mn 2 O 3 composited α-Fe 2 O 3 all enhance the catalytic efficiency. • Transition metal composites of α-Fe 2 O 3 efficiently work at pH 6.8 and [O 3 ] = 30 μg/L. • Polyvalent metal atoms promote electron transfer and Fe2+/Fe3+ cycling. • Electron transfer capacities (Mn > Cu > Zn) correspond to ROSs production levels. • Mn 2 O 3 /α-Fe 2 O 3 exhibits the highest efficiency and detoxification capability for SMX. [ABSTRACT FROM AUTHOR]

[Display omitted] • Amino polycarboxylic acid complex agents modified-Fe0 (APCAs-Fe0) contained a better activity than Fe0. • APCAs-Fe0/H 2 O 2 process could efficient remove TC compared with Fe0/H 2 O 2 process under neutral conditions. • Both dioxygen coordination and single oxygen coordination H 2 O 2 decomposition pathway were present in APCAs-Fe0/H 2 O 2 system. • APCAs-Fe0 could enhance H 2 O 2 decomposition in both two H 2 O 2 decomposition pathways. • APCAs' carboxyl groups played a crucial role in enhancing catalytic activity of APCAs-Fe0. The summary of this study explores the modification of Fe0 with amino polycarboxylic acid complex agents (APCAs) to enhance H 2 O 2 catalysis for tetracycline (TC) removal under neutral conditions. The ethylenediaminetetraacetic acid-modified Fe0/H 2 O 2 system (EDTA-Fe0/H 2 O 2) achieved a removal efficiency of 90.2 % for 50 mg/L TC, significantly higher than the 23.9 % efficiency of the traditional Fe0/H 2 O 2 system. The removal rate of various pollutants by the EDTA- Fe0/H 2 O 2 process is 2.9 to 8.4 times higher than that of the Fe0/H 2 O 2 process. After four cycles of use, the removal rate of TC by the EDTA-Fe0/H 2 O 2 system can still reach 76.3 %. Additionally, the effect of treating TC in natural freshwater can also achieve 80.1 %. Characterization revealed that EDTA-Fe0 had a larger Fe(II) proportion, better hydrophobicity, and lower corrosion potential than Fe0, indicating higher activity. Quenching experiments and electron paramagnetic resonance tests confirmed that •OH was the major reactive species. Shell-isolated nanoparticle-enhanced Raman spectroscopy indicated the presence of *OOH species, suggesting the involvement of a dioxygen coordination reaction. Density functional theory calculations showed that both dioxygen and single oxygen coordination H 2 O 2 decomposition pathways played significant roles, and EDTA-Fe0 exhibited high catalysis ability for H 2 O 2 in both pathways. Analysis of the relationship between APCAs' group structure and APCAs-Fe0 properties indicated that the number of carboxyl groups was crucial for enhancing catalytic activity, while the number of amino groups also impacted antibiotic removal efficiency. Overall, this study provides a solid theoretical foundation for further Fe0 applications and suggests a new method to improve TC removal. [ABSTRACT FROM AUTHOR]

[Display omitted] • PCA greatly improved SMX removal in Fe(III)/PMS process under truly pH conditions. • PCA-Fe(III)-OOSO 3 - was proposed as the primary reactive species for SMX removal. • The toxicity of SMX solution declined after treatment with PCA/Fe(III)/PMS process. • PCA/Fe(III)/PMS process had strong anti-interference ability to water matrix. • PCA/Fe(III)/PMS process exhibited high SMX removal efficiency in nature waters. Protocatechuic acid (PCA) has been extensively employed as reducing agent to improve the Fenton-like processes under acidic pH conditions by accelerating the Fe(II)/Fe(III) redox cycle. Nevertheless, the potential of PCA as chelating agent to enable Fenton-like processes for contaminant elimination under neutral pH conditions has been overlooked. In this study, experiments and DFT calculations demonstrate that PCA can improve the elimination of sulfonamide antibiotics in Fe(III)/peroxymonosulfate (PMS) process under truly neutral pH conditions by improving the catalytic reactivity of Fe(III) with PMS, resulting in a 23.74-fold increase in the pseudo-first order rate constant (k obs) of sulfamethoxazole (SMX) removal at pH 7.0. Meanwhile, the k obs of SMX removal in PCA/Fe(III)/PMS process was 10–60 times higher than that in various previously reported strategies-enhanced Fe(III)/PMS processes at pH 7.0. The Fe(III)-peroxo intermediate (PCA-Fe(III)-OOSO 3 -), rather than •OH, SO 4 •-, Fe(IV)/Fe(V) and 1O 2 , was identified as the primary reactive species responsible for SMX removal in PCA/Fe(III)/PMS process under neutral pH conditions. DFT results indicate that PCA increased the oxidation potential of Fe(III)-OOSO 3 -. Meanwhile, PCA/Fe(III)/PMS process exhibited promising applicability in natural waters with strong anti-interference capability even with 5 μM Fe(III). Additionally, five potential elimination pathways of SMX were proposed, and the toxicity of treated SMX solution decreased. This study investigated the overlooked but crucial role of PCA in Fe(III)/PMS process under neutral pH conditions, which may provide novel insights into the underlying mechanism of PCA-enhanced Fenton-like processes and provide viable options for the application of Fe-catalyzed PMS processes in neutral waters. [ABSTRACT FROM AUTHOR]

In this study, Fe-Cu binary oxide was loaded on zeolite (Fe/Cu/zeolite) to be used as heterogeneous Fenton catalyst, and the catalytic degradation of carbamazepine (CBZ) were optimized at near-neutral pH. The results showed that the Fe and Cu oxide, mainly Fe2O3, Fe3O4, and CuO nanoparticles, were uniformly distributed on the surface of zeolite particles. Under the optimized conditions, Fe/Cu/zeolite could completely degrade CBZ when initial pH ranged from 3 to 7, and the removal efficiency of CBZ still remained above 74% even though the initial pH increased to near 10. After 8 times' repeated use, the Fe/Cu/zeolite exhibited an over 95% removal efficiency of CBZ. The hydroxyl radicals (•OH) were verified to be the main active oxidants by quenching experiments and ESR testing. The XPS of the materials revealed that the high catalytic efficiency was attributed to the synergistic effect of Fe(III)/Fe(II) and Cu(II)/Cu(I) redox cycles. This catalyst can be used for the efficient degradation of organic pollutants in heterogeneous Fenton systems. [ABSTRACT FROM AUTHOR]

Catalytic oxidation of 3,3',5,5'-Tetramethylbenzidine (TMB, an excellent chromogenic substrate) at neutral pH is critically important for amplified bioanalysis. Although some nanozymes exhibited the peroxidase activity at neutral pH, it is difficult to modulate their activity for homogeneous detection of biomolecules. In this work, we developed a redox-mediated dsDNA-dye photooxidase mimic that enables catalytic oxidation of TMB by dissolved O 2 at neutral pH for improved biosensing. During illumination, the double-stranded DNA-SYBR Green I (dsDNA-SG) photogenerated singlet oxygen ( 1 O 2 ) can oxidized Mn 2+ to Mn 3+ that can efficiently oxidize TMB to produce a distinct blue within 4 min under neutral conditions. The catalytic oxidation of TMB can be readily modulated by the formation or dissociation of dsDNA during the sensing. After investigating a series of redox mediators, we found that only the Mn 3+ /Mn 2+ redox mediator can lead to the oxidation of TMB at neutral pH. The maximum reaction rate of Mn 2+ -mediated dsDNA-SG photooxidase mimic under neutral conditions (pH 7.0) was 1.7 × 10 -4  mM/s, even higher than that of horseradish peroxidase (HRP, 8.0 × 10 -5  mM/s). The redox-mediated dsDNA-SG photooxidase mimic was used for detection of APE1 at pH 7.0 with over 130-fold higher sensitivity than that at 4.0, owing to the high enzymatic activity of APE1 at neutral pH. Meanwhile, we further extended this photooxidase mimic for the sensitive detection of DNA (LOD, 8 pM) and heavy metal ions at neutral pH. The redox-mediated dsDNA-dye photooxidase mimic with the ease of modulating its enzymatic activity and working at neutral pH is quite appealing for biosensing., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier B.V. All rights reserved.)

The lack of effective and non-corrosive hole-transporting layer (HTL) materials has remained a long-standing issue that severely restricts the performance of organic solar cells (OSCs). Most pH-neutral conjugated polyelectrolytes (CPEs) exhibit inferior performance to the acid-doped HTL materials due to their low doping density. In this study, a series of pH-neutral CPEs is designed and synthesized with high doping density as HTL materials. Through an elaborate synthetic route, two sulfonate-terminating alkoxyl side chains can be introduced into thiophene, by which the electron-rich, highly soluble, and chemically stable thiophene monomer is synthesized to enable the subsequent polymerization. The CPE PTT-F exhibit a remarkable self-doping property with an enhanced doping density from 2.01 × 10 17 to 7.02 × 10 18 cm -3 . The high work function and the increased doping density of PTT-F-based HTL decrease the depletion region width from 38.4 to 8.1 nm at the anode interface, which minimized the energy loss in hole transport. Consequently, a binary OSC modified by PTT-F-based HTL achieve a high PCE of 18.8%. To the best of the knowledge, this is the highest PCE for OSC employing CPE-based HTL. The results from this work demonstrate an encouraging achievement of realizing exceptional hole collection ability in pH-neutral CPEs., (© 2024 Wiley‐VCH GmbH.)

A heterojunction photo-electrode(s) consisting of porous black titanium oxide (bTiO 2 ) and electrochemically self-activated TaS 2 flakes is proposed and utilized for hydrogen evolution reaction (HER). The self-activated TaS 2 flakes provide abundant catalytic sites for HER and the porous bTiO 2 , prepared by electrochemical anodization and subsequent reduction serves as an efficient light absorber, providing electrons for HER. Additionally, Au nanostructures are introduced between bTiO 2 and TaS 2 to facilitate the charge transfer and plasmon-triggering ability of the structure created. After structure optimization, high HER catalytic activity at acidic pH and excellent HER activity at neutral pH are achieved at high current densities. In particular, with the utilization of bTiO 2 @TaS 2 photoelectrode (neutral electrolyte, sunlight illumination) current densities of 250 and 500 mA cm -2 are achieved at overpotentials of 433, and 689 mV, respectively, both exceeding the "benchmark" Pt. The addition of gold nanostructures further reduces the overpotential to 360 and 543 mV at 250 and 500 mA cm -2 , respectively. The stability of the prepared electrodes is investigated and found to be satisfying within 24 h of performance at high current densities. The proposed system offers an excellent potential alternative to Pt for the development of green hydrogen production on an industrial scale., (© 2024 The Author(s). Small published by Wiley‐VCH GmbH.)

Energy storage devices based on earth-abundant materials are key steps towards portable and sustainable technologies used in daily life. Pseudocapacitive devices, combining high power and high energy density features, are widely required, and transition metal oxides represent promising building materials owing to their excellent stability, abundance, and ease of synthesis. Here, we report an original ZnO-based nanostructure, named nanostars (NSs), obtained at high yields by chemical bath deposition (CBD) and applied as pseudocapacitors. The ZnO NSs appeared as bundles of crystalline ZnO nanostrips (30 nm thin and up to 12 µm long) with a six-point star shape, self-assembled onto a plane. X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL) were used to confirm the crystal structure, shape, and defect-mediated radiation. The ZnO NSs, dispersed onto graphene paper, were tested for energy storage by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analyses, showing a clear pseudocapacitor behavior. The energy storage mechanism was analyzed and related to oxygen vacancy defects at the surface. A proper evaluation of the charge stored on the ZnO NSs and the substrate allowed us to investigate the storage efficiency, measuring a maximum specific capacitance of 94 F   g − 1 due to ZnO nanostars alone, with a marked diffusion-limited behavior. The obtained results demonstrate the promising efficacy of ZnO-based NSs as sustainable materials for pseudocapacitors. [ABSTRACT FROM AUTHOR]

In this research, a brush-like polyaniline (poly(2-acrylamide-2-methyl-1-propanesulfonate)-g-polyaniline)-b-poly(N-vinylcarbazole) (BL PAni) was developed as a strategy to overcome the limited processability and dedoping above pH 4 of conventional polyaniline (PAni). For the BL PAni synthesis, RAFT polymerization (homopolymer), RAFT-mediated surfactant-free emulsion polymerization (block copolymer), and interfacial oxidative polymerization were applied to graft the PAni chains. NMR and FT-IR spectroscopies were performed to confirm the structural elucidation of the reaction pathways, while the thermal properties were analyzed by TGA and DSC. Notably, the BL PAni presents absorption throughout the visible region and up to the near-infrared, showing dedoping resistance at up to 80 °C and at a neutral pH. The absorption range of the BL PAni, block copolymer, and homopolymer were studied by UV–Vis spectroscopy in solid-state and dispersion/solution, highlighting BL PAni and poly(anilinium 2-acrylamide-2-methyl-1-propanesulfonate)-b-poly(N-vinylcarbazole) (PAAMP-b-PVK) due to the π-stacking between the anilinium and carbazole groups. The cyclic voltammetry confirmed the persistence of electroactivity at a pH near 7. [ABSTRACT FROM AUTHOR]

• The EC/PMS/Fe(III)-EDTA system was tested under a pH range of 3–9. • Fe(II)-EDTA complex maintains high reaction rates to degrade ACA at neutral pH. • •OH, 1O 2 , SO 4 •− and Fe(IV) are the dominant reactive species in the system. • The addition of EDTA established a new pathway for producing 1O 2 in the system. • ACA degradation pathways and byproducts were revealed based on mass spectra. In this work, ethylene diamine tetraacetic acid (EDTA) was applied as a chelating agent to stabilize Fe(III)/Fe(II) cycle to effectively activate peroxymonosulfate (PMS) in an electrochemical (EC) co-catalytic system for elimination of naphthenic acids (NAs) under neutral pH condition. 1-Adamantanecarboxylic acid (ACA) was applied as the model compound for NAs that are persistent contaminants in petroleum industrial wastewater. In the PMS/EC/Fe(III)-EDTA system, complete removal of ACA has been achieved in 20-min reaction under neutral pH condition. Degradation mechanisms were investigated via electron paramagnetic resonance (EPR) analysis, probe experiments and quenching experiments to reveal the reactive species •OH, SO 4 •− and 1O 2 for ACA removal, the production of which have been significantly facilitated by the introduction of EDTA complex. A new pathway has been found for the production of 1O 2 via several intermediates including hydrogen peroxide and superoxide radicals. Density functional theory (DFT) calculations and mass spectrometry analysis were applied to predict ACA degradation pathways and byproducts. Decarboxylation, hydroxyl substitution and carbonyl substitution byproducts of ACA were detected. The PMS/EC/Fe(III)-EDTA system suffered nonimportant influence at the presence of humic acid, H 2 PO 4 -, HCO 3 –, NO 3 – and Cl- for ACA removal. Overall results demonstrate the effectiveness and reliability of the PMS/EC/Fe(III)-EDTA system for efficient removal of NAs in petroleum wastewater in natural environment under neutral pH condition. [ABSTRACT FROM AUTHOR]

• PCA improved SMX removal in Fe(III)/PAA system under truly neutral pH conditions. • PCA enhanced the catalytic activity of Fe(III) on PAA under neutral pH conditions. • CH 3 C(O)OO-Fe(III)-PCA was proposed as the primary reactive specie for SMX removal. • PCA/Fe(III)/PAA system had strong anti-interference ability to water constituents. • PCA/Fe(III)/PAA system exhibited high SMX removal efficiency in nature waters. The practical application of the Fe-catalyzed peracetic acid (PAA) processes is seriously restricted due to the need for narrow pH working range and poor anti-interference capacity. This study demonstrates that protocatechuic acid (PCA), a natural and eco-environmental phenolic acid, significantly enhanced the removal of sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions (6.0–8.0) by complexing Fe(III). With sulfamethoxazole (SMX) as the model contaminant, the pseudo-first-order rate constant of SMX elimination in PCA/Fe(III)/PAA process was 63.5 times higher than that in Fe(III)/PAA process at pH 7.0, surpassing most of the previously reported strategies-enhanced Fe-catalyzed PAA processes (i.e., picolinic acid and hydroxylamine etc.). Excluding the primary contribution of reactive species commonly found in Fe-catalyzed PAA processes (e.g., •OH, R-O•, Fe(IV)/Fe(V) and 1O 2) to SMX removal, the Fe(III)-peroxy complex intermediate (CH 3 C(O)OO-Fe(III)-PCA) was proposed as the primary reactive species in PCA/Fe(III)/PAA process. DFT theoretical calculations indicate that CH 3 C(O)OO-Fe(III)-PCA exhibited stronger oxidation potential than CH 3 C(O)OO-Fe(III), thereby enhancing SMX removal. Four potential removal pathways of SMX were proposed and the toxicity of reaction solution decreased with the removal of SMX. Furthermore, PCA/Fe(III)/PAA process exhibited strong anti-interference capacity to common natural anions (HCO 3 −, Cl−and NO 3 −) and humic acid. More importantly, the PCA/Fe(III)/PAA process demonstrated high efficiency for SMX elimination in actual samples, even at a trace Fe(III) dosage (i.e., 5 μM). Overall, this study provided a highly-efficient and eco-environmental strategy to remove sulfonamide antibiotics in Fe(III)/PAA process under actually neutral pH conditions and to strengthen its anti-interference capacity, underscoring its potential application in water treatment. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Impact of surface properties on the effective anchoring of AuNPs on CNTs. • Physicochemical properties/electrochemical performance relationship. • Efficient DCF sensing at neutral pH achieving an LOD of 185 nM. • High recovery of DCF determination in tap water sample analysis. • Improved sensor reproducibility and repeatability after AuNPs addition. MWCNT-based materials and derived composites with AuNPs were investigated as GCE modifiers for the indirect electrochemical detection of DCF. The morphology and surface chemistry, paying special attention to the influence of the type and distribution of oxygen functional groups on the electrochemical performance of the sensor, were assessed. The higher content and more homogeneous distribution of AuNPs were revealed on the surface of CNTs-COOH compared to CNTs-OH. The detection of DCF was performed at neutral pH being beneficial for real sample analysis. Enhanced sensor performance for DCF recorded on GCE/CNTs-COOH-AuNPs resulted in a low LOD = 185 nM, a wide LR = 0.3–120 µM and appropriate long-term behavior. Moreover, good recoveries of the proposed sensor were validated by testing tap water samples. These results, explained by the excellent characteristics of CNTs-COOH-AuNPs as active electrode materials, represent a significant step forward in the development of sensors for detecting small amounts of analytes in wastewater samples. [ABSTRACT FROM AUTHOR]

γ-aminobutyric acid (GABA) has various physiological functions and is widely used in medicine, food, and other fields. Glutamate decarboxylase (GAD) is a key enzyme that catalyzes the decarboxylation of L-glutamate to synthesize GABA. However, the industrial application of microorganism-derived GAD is limited by its rapid loss of enzymatic activity with pH approaching neutrality. In this study, a novel glutamate decarboxylase, GADMSM, from Mycobacterium smegmatis was overexpressed and purified. On the basis of homologous modeling and substrate molecular docking, several GADMSM mutants were constructed, and their enzymatic properties were analyzed. The results showed that the optimal pH of wild-type GADMSM is 5.4; at pH 6.2, 22.8% enzymatic activity was retained. The T211I replacement in GAD and C-terminal deletion mutant GADMSMΔC showed relatively high catalytic activity in a pH range of 5.0–7.0. The Vmax and Km values of GADMSMΔC were 14.69 and 5.70, respectively, at pH 5.5, and 9.87 and 6.17, respectively, at pH 7.0. Compared with the wild-type GAD, GADMSMΔC maintained higher affinity and enzymatic activity of the substrate, maintaining 78.5% of the highest enzymatic activity even at pH 7.0, which is the highest reported activity retention for GAD under neutral pH condition. Therefore, GADMSMΔC can be used for the transformation of high-yielding strains and industrial production of GABA. [ABSTRACT FROM AUTHOR]

Ni-ethylenediaminetetraacetic acid (Ni-EDTA) poses serious threats to the ecological environment and human health, due to its acute toxicity and low biodegradability. The decomplexation efficiency of Ni-EDTA through the conventional Fenton process has been constrained to pH; thus, other appropriate approaches are required to destroy the stable chelate structure at a neutral pH. In this study, the effect of operating parameters such as the pH, Fe2+ concentration, particle electrode dosage, current density, and coexisting ions was studied. The results revealed that the 3D-EF system owned advantages for the removal of Ni-EDTA in the broadening of the pH application window. The Ni-EDTA removal efficiency in the 3D-EF system reached 84.89% after 120 min at a pH of 7. In addition, the presence of coexisting ions slightly affected the decomplexation efficiency of Ni-EDTA. [ABSTRACT FROM AUTHOR]

Although PEDOT:PSS is the most prominently used conducting polymer as hole transporting layer (HTL) material in organic solar cells (OSCs), the strong acidity of PEDOT:PSS has been proved to cause corrosion on electrodes, which is largely responsible for device instability. At present, the development of a non‐corrosive and stable PEDOT with comparable performance to PEDOT:PSS remains a great challenge in the field. Herein, a solid n‐PEDOT:POM powder with neutral pH is synthesized by utilizing polyoxometalate (POM) as an oxidizing reagent, which exhibits excellent water solubility, high chemical stability, and superior hole collection ability. Impressively, an amazing fill factor of 0.80 along with a photovoltaic efficiency of 17.62% is obtained in the OSC by using n‐PEDOT:POM as the HTL, suggesting an exceptional hole collection ability for n‐PEDOT:POM. In addition, the neutral pH of PEDOT:PSS effectively improves the long‐term stability of OSCs. X‐ray photoelectron spectroscopy results reveal that, compared to the electrode/PEDOT:PSS interface, the permeation of dissociative indium from the electrode to n‐PEDOT:POM can be greatly retarded, which proves the non‐corrosive effect of n‐PEDOT:POM and its improvement of device stability. The successful preparation of a non‐corrosive and stable PEDOT derivative without sacrificing its hole collection ability provides the most fruitful new insight into developing high‐performance HTL materials. [ABSTRACT FROM AUTHOR]

Abstract A simple and cost-effective electrochemical synthesis of carbon-based nanomaterials for electrochemical biosensor is of great challenge these days. Our study describes a single-step electrochemical deposition strategy to prepare a nanocomposite of electrochemically reduced graphene oxide (ErGO), multi-walled carbon nanotubes (MWCNTs), and polypyrrole (PPy) in an aqueous solution of pH 7.0 for dopamine (DA) detection. The ErGO/MWCNTs/PPy nanocomposites show enhanced electrochemical performance due to the strong π–π* stacking interactions among ErGO, MWCNTs, and PPy. The efficient interaction of the nanocomposites is confirmed by evaluating its physical and electrochemical characteristics using field-emission scanning electron microscopy, Raman spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The deposited nanocomposites are highly stable on the substrates and possess high surface areas, which is vital to improve the sensitivity and selectivity for DA detection. The controlled deposition of the ErGO/MWCNTs/PPy nanocomposites can provide enhanced electrochemical detection of DA. The sensor demonstrates a short time response within 2 s and is a highly sensitive approach for DA detection with a dynamic linear range of 25–1000 nM (R 2 = 0.999). The detection limit is estimated to be 2.3 nM, and the sensor sensitivity is calculated to be 8.96 μA μM−1 cm−2, with no distinct responses observed for other biological molecules.

Rhinoviruses (RVs) cause recurrent infections of the nasal and pulmonary tracts, life-threatening conditions in chronic respiratory illness patients, predisposition of children to asthmatic exacerbation, and large economic cost. RVs are difficult to treat. They rapidly evolve resistance and are genetically diverse. Here, we provide insight into RV drug resistance mechanisms against chemical compounds neutralizing low pH in endolysosomes. Serial passaging of RV-A16 in the presence of the vacuolar proton ATPase inhibitor bafilomycin A1 (BafA1) or the endolysosomotropic agent ammonium chloride (NH4Cl) promoted the emergence of resistant virus populations. We found two reproducible point mutations in viral proteins 1 and 3 (VP1 and VP3), A2526G (serine 66 to asparagine [S66N]), and G2274U (cysteine 220 to phenylalanine [C220F]), respectively. Both mutations conferred cross-resistance to BafA1, NH4Cl, and the protonophore niclosamide, as identified by massive parallel sequencing and reverse genetics, but not the double mutation, which we could not rescue. Both VP1-S66 and VP3-C220 locate at the interprotomeric face, and their mutations increase the sensitivity of virions to low pH, elevated temperature, and soluble intercellular adhesion molecule 1 receptor. These results indicate that the ability of RV to uncoat at low endosomal pH confers virion resistance to extracellular stress. The data endorse endosomal acidification inhibitors as a viable strategy against RVs, especially if inhibitors are directly applied to the airways. [ABSTRACT FROM AUTHOR]

A series of novel MnxFey@SiO2 (x,y = 1–20%) nanocomposites were synthesized for the first time via the sol-gel/combustion method with different content of precursors (Mn and Fe acetate salts). The effect of precursor content and ratio on physicochemical properties were observed by various characterization methods. Moreover, Rhodamine B (RhB) was chosen as the target pollutant to test the performance of these nanocomposites under a photocatalytic Fenton-like reaction. The results showed that the nanocomposite morphology improved by increasing Fe and Mn content. In this study, interesting behavior was observed in BET results which were different from the fact that increasing metal content can decrease the surface area. This study revealed that one metal could be more critical in controlling the properties than another. Moreover, the precursor ratio appears to have a more tangible effect on the surface area than the effect of precursor content. Among all synthesized nanocomposites, Mn1Fe5@SiO2 showed the highest surface area of 654.95 m2/g. At optimum batch conditions (temp = 25 °C, catalyst dosage = 1 g L−1, H2O2 = 75 mmolL−1, and initial RhB concentration = 50 mg L−1), complete removal (simultaneous adsorption/degradation) occurred using Mn1Fe5@SiO2 at neutral pH. This study showed that the designed nanomaterial could be used as a dual functional adsorbent/photocatalyst in different environmental applications.

• Au doping enabled the neutral pH photozymatic activity of C 3 N 4 nanosheets. • A colorimetric method for rapid and simple TAC detection at a neutral pH was developed. • Boosted ROS generation and higher substrate affinity are key to the neutral pH photozymatic activity. Total antioxidant capacity (TAC) is vital for food quality evaluation. The emergence of various nanozymes with TMB as substrate offered a new avenue for TAC detection due to simple operation and fast response, but a long-standing challenge is its low activity at physiological pH, which may account for the discrepancy between the measured TAC and the actual antioxidant capacity in vivo. Herein, Au doping was explored to break the pH limitation of g-C 3 N 4 nanosheets (CNNS) photozyme. The catalytic activities of Au@CNNS at pH 4.0 and 7.4 were 14.9- and 6.2-fold higher than that of CNNS at pH 4. The neutral pH photozymatic activity (photosensitized oxidation of TMB, oxidase mimic) of Au@CNNS was explored for sensitivity TAC detection (LOD: 1.0 μM TE), which featured more convenient operations and higher sensitivity over the DPPH assay. The proposed Au@CNNS-based photozymatic colorimetric method was explored for accurate detection of TAC in drinks and juices. [ABSTRACT FROM AUTHOR]

We proposed to establish nanoscale spatially confined Fenton treatment architectures to overcome the catalyst deactivation issue frequently seen at neutral pH. We demonstrated this idea by growing four typical iron oxide catalysts (Fe 3 O 4 , FeOOH, CuFe 2 O 4 , and FeOCl), respectively inside the nanochannels of anodized aluminum oxide scaffold, wherein the confined space (≈5 nm) significantly accelerated heterogeneous Fenton treatment of organic pollutants, with up to 310 times kinetics enhancement under normalized surface area compared to the counterpart bulk reactions with suspension catalysts. Based on experimental and computational studies, we gained the mechanistic details on how did the nanoconfinement enhanced the protonation of surfaces driving the catalysis, and showed how much of its significance over other influencing factors on enhancing the treatment kinetics and a sustained catalysis. Our findings mark an important advance on developing nanoconfined Fenton treatment systems that enable efficient catalyst activation and maximal treatment kinetics, without additional chemicals or electro-/photo-energies. [Display omitted] • Nanoconfinement control is shown feasible to activate Fenton catalyst at neutral pH. • Mechanisms for confinement-induced surface protonation effect were revealed. • Confined treatment kinetics was maximized with enhanced •OH production and exposure. • Smart nanoreactor design involves catalyst structure, charge property, and pore size. [ABSTRACT FROM AUTHOR]

• Developed oxalic acid (OA) chelated electrochemical (EF) released Fe2+ activated CaO 2 pre-conditioned sludge process. • EF-CaO 2 /OA effectively enhanced sludge dewaterability at neutral pH. • EF-CaO 2 /OA provides durable and effective oxidizing power. • End-of-conditioned sludge was still pH-neutral. • Altered protein secondary structure transforms sludge from hydrophilic to hydrophobic. In this study, we investigated the efficiency of activation of CaO 2 by oxalic acid (OA) chelated with electrochemically (EF)-released Fe2+ (EF-CaO 2 /OA) in improving the performance of sludge dewatering under neutral conditions. We also explored the mechanism of OA-reinforcement of EF-CaO 2 in enhancing the performance of wastewater-activated sludge dewatering by investigating the water content (Wc), specific resistance to filtration (SRF), pH, bound water content, extracellular polymers in the sludge, the secondary structure of proteins, the soluble ferric ions, and the morphology of the sludge. The EF-CaO 2 /OA process was better than the EF-CaO 2 process in terms of sludge dewatering. OA introduction significantly inhibited the increase of solution pH, which in turn promoted CaO 2 dissolution and persistent H 2 O 2 generation. The persistent oxidative reaction contributed to the degradation of hydrophilic protein fractions in EPS and the reduction of the proportion of hydrophilic structures in the secondary structure of proteins, which in turn improved the hydrophobicity of the sludge. The changing profile of DNA content in EPS proved that EF-CaO 2 /OA led to the damage of more sludge cells. It suggested that OA enhanced the oxidizing efficacy of EF-CaO 2 , which in turn promoted the release of bound water from more sludge cells. Moreover, OA significantly increased the amount of dissolved iron in solution by chelating the electrochemically released iron, which contributed to the stabilization of the oxidation reaction. Under the optimal conditions, sludge Wc and SRF treated by EF-CaO 2 /OA were reduced by 30.1% and 96.9%, respectively, and the dewatered sludge cake remained neutral. In conclusion, EF-CaO 2 /OA may be an efficient and feasible technique for deep sludge dewatering. [ABSTRACT FROM AUTHOR]

Energy storage devices based on earth-abundant materials are key steps towards portable and sustainable technologies used in daily life. Pseudocapacitive devices, combining high power and high energy density features, are widely required, and transition metal oxides represent promising building materials owing to their excellent stability, abundance, and ease of synthesis. Here, we report an original ZnO-based nanostructure, named nanostars (NSs), obtained at high yields by chemical bath deposition (CBD) and applied as pseudocapacitors. The ZnO NSs appeared as bundles of crystalline ZnO nanostrips (30 nm thin and up to 12 µm long) with a six-point star shape, self-assembled onto a plane. X-ray diffraction (XRD), scanning electron microscopy (SEM), and photoluminescence spectroscopy (PL) were used to confirm the crystal structure, shape, and defect-mediated radiation. The ZnO NSs, dispersed onto graphene paper, were tested for energy storage by cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD) analyses, showing a clear pseudocapacitor behavior. The energy storage mechanism was analyzed and related to oxygen vacancy defects at the surface. A proper evaluation of the charge stored on the ZnO NSs and the substrate allowed us to investigate the storage efficiency, measuring a maximum specific capacitance of 94 F g−1 due to ZnO nanostars alone, with a marked diffusion-limited behavior. The obtained results demonstrate the promising efficacy of ZnO-based NSs as sustainable materials for pseudocapacitors.

The development of neutral pH polymer electrolytes has enabled high-performance solid-state, thin, and flexible electrochemical capacitors (ECs) to provide power for future consumer electronics and Internet-of-Thing devices. Notwithstanding their promising prospect, there is still some lack of understandings or disconnections from fundamental science to practical applications of these electrolytes. In this review, we provide an overview of state-of-the-art studies on ECs with neutral pH electrolytes in both liquid and solid configurations. Starting from the fundamental studies on the voltage window and ion conduction of salt species in liquid solution to polymer electrolytes, key considerations in developing neutral pH polymer electrolytes are discussed. The performance of the polymer electrolytes along with their enabled solid symmetric and asymmetric EC devices, as well as some enhanced functionalities are presented. The future directions for research on neutral pH polymer electrolytes are proposed, expected to provide reference for further enriching the fundamental knowledge and improving the device performances.

Ni-ethylenediaminetetraacetic acid (Ni-EDTA) poses serious threats to the ecological environment and human health, due to its acute toxicity and low biodegradability. The decomplexation efficiency of Ni-EDTA through the conventional Fenton process has been constrained to pH; thus, other appropriate approaches are required to destroy the stable chelate structure at a neutral pH. In this study, the effect of operating parameters such as the pH, Fe2+ concentration, particle electrode dosage, current density, and coexisting ions was studied. The results revealed that the 3D-EF system owned advantages for the removal of Ni-EDTA in the broadening of the pH application window. The Ni-EDTA removal efficiency in the 3D-EF system reached 84.89% after 120 min at a pH of 7. In addition, the presence of coexisting ions slightly affected the decomplexation efficiency of Ni-EDTA.

Strain hardening, i.e., the nonlinear elastic response of materials under load, is a physiological response of biological tissues to mechanical stimulation. It has recently been shown to play a central role in regulating cell fate. In this paper, we investigate the effect of temperature and polymer concentrations on the strain hardening of covalent hydrogels composed of pH-neutral soluble chitosans crosslinked with genipin. A series of highly acetylated chitosans with a fraction of acetylated units, FA, in the range of 0.4–0.6 was synthesized by the homogeneous re-N-acetylation of a partially acetylated chitosan or the heterogeneous deacetylation of chitin. A chitosan sample with an FA = 0.44 was used to prepare hydrogels with genipin as a crosslinker at a neutral pH. Time and frequency sweep experiments were then performed to obtain information on the gelling kinetics and mechanical response of the resulting hydrogels under small amplitude oscillatory shear. While the shear modulus depends on the chitosan concentration and is almost independent of the gel temperature, we show that the extent of hardening can be modulated when the gelling temperature is varied and is almost independent of the experimental conditions used to build the hydrogels (ex situ or in situ gelation). The overall effect is attributed to a subtle balance between the physical (weak) entanglements and covalent (strong) crosslinks that determine the mechanical response of highly acetylated chitosan hydrogels at large deformations.

A simple and cost-effective electrochemical synthesis of carbon-based nanomaterials for electrochemical biosensor is of great challenge these days. Our study describes a single-step electrochemical deposition strategy to prepare a nanocomposite of electrochemically reduced graphene oxide (ErGO), multi-walled carbon nanotubes (MWCNTs), and polypyrrole (PPy) in an aqueous solution of pH 7.0 for dopamine (DA) detection. The ErGO/MWCNTs/PPy nanocomposites show enhanced electrochemical performance due to the strong π–π* stacking interactions among ErGO, MWCNTs, and PPy. The efficient interaction of the nanocomposites is confirmed by evaluating its physical and electrochemical characteristics using field-emission scanning electron microscopy, Raman spectroscopy, electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The deposited nanocomposites are highly stable on the substrates and possess high surface areas, which is vital to improve the sensitivity and selectivity for DA detection. The controlled deposition of the ErGO/MWCNTs/PPy nanocomposites can provide enhanced electrochemical detection of DA. The sensor demonstrates a short time response within 2 s and is a highly sensitive approach for DA detection with a dynamic linear range of 25–1000 nM (R2 = 0.999). The detection limit is estimated to be 2.3 nM, and the sensor sensitivity is calculated to be 8.96 μA μM−1 cm−2, with no distinct responses observed for other biological molecules. [ABSTRACT FROM AUTHOR]

Exploration of high-efficiency and inexpensive electrode catalysts is of vital importance for the hydrogen evolution reaction (HER). In this research, an amorphous Co-Al-P layer was constructed on the surface of CoAl layered double hydroxide (CoAl-LDH) via an in-situ wet phosphidation strategy. The core-shell CoAl-LDH@Co-Al-P on Ti mesh (CoAl-LDH@Co-Al-P/TM) as an active HER electrocatalyst demands an overpotential of 150 mV to achieve a current density of 10 mA cm−2 at neutral pH. Moreover, CoAl-LDH@Co-Al-P/TM also exhibits good electrochemical stability and a superior Faradic efficiency of nearly 100%.

The present work reported a modified persulfate activation process with a microbial siderophore named desferrioxamine B (DFOB). DFOB was a natural complexing agent and could complex with Fe3+ strongly. The photochemical reactivity of Fe(III)-DFOB was studied. Fe2+ and HO• were produced from Fe(III)-DFOB photolysis. Furthermore, the degradation of atenolol (ATL) was followed in light/persulfate (PS)/Fe(III)-DFOB system. The main oxidative radicals were SO4•− in this system. The results of pH effect showed that there was no obviously fluctuation on ATL degradation efficiency with the pH increased from 2.5 to 8.4. Moreover, kSO4•−,DFOB was determined by laser flash photolysis (LFP) experiments. DFOB had positive effect on Fe2+ formation but negative effect on ATL degradation due to the high react rate constant between DFOB and SO4•−. The effects of chloride and carbonate ion were also investigated. The results in this study proposed the reaction mechanism of the modified persulfate activation process, and it could be applied in neutral and weak-alkaline pH range. [ABSTRACT FROM AUTHOR]

A highly stable phosphonate‐functionalized viologen is introduced as the redox‐active material in a negative potential electrolyte for aqueous redox flow batteries (ARFBs) operating at nearly neutral pH. The solubility is 1.23 m and the reduction potential is the lowest of any substituted viologen utilized in a flow battery, reaching −0.462 V versus SHE at pH = 9. The negative charges in both the oxidized and the reduced states of 1,1′‐bis(3‐phosphonopropyl)‐[4,4′‐bipyridine]‐1,1′‐diium dibromide (BPP−Vi) effect low permeability in cation exchange membranes and suppress a bimolecular mechanism of viologen decomposition. A flow battery pairing BPP−Vi with a ferrocyanide‐based positive potential electrolyte across an inexpensive, non‐fluorinated cation exchange membrane at pH = 9 exhibits an open‐circuit voltage of 0.9 V and a capacity fade rate of 0.016% per day or 0.00069% per cycle. Overcharging leads to viologen decomposition, causing irreversible capacity fade. This work introduces extremely stable, extremely low‐permeating and low reduction potential redox active materials into near neutral ARFBs. [ABSTRACT FROM AUTHOR]

Bacterial sialidases are widely used to remove sialic acid (Sia) residues from glycans. Most of them cleave the glycosides of N -acetylneuraminic acid (Neu5Ac) and N -glycolylneuraminic acid (Neu5Gc) under acidic pHs; however, currently available bacterial sialidases had no activity to the glycosides of deaminoneuraminic acid (Kdn). In this study, we found a novel sialidase from Sphingobacterium sp. strain HMA12 that could cleave any of the glycosides of Neu5Ac, Neu5Gc, and Kdn. It also had a broad linkage specificity, i.e., α2,3-, α2,6-, α2,8-, and α2,9-linkages, and the optimal pH at neutral ranges, pH 6.5–7.0. These properties are particularly important when sialidases are applied for in vivo digestion of the cell surface sialosides under physiological conditions. Interestingly, 2,3-didehydro-2-deoxy- N -acetylneuraminic acid (Neu5Ac2en), which is a transition state analog-based inhibitor, competitively inhibited the enzyme-catalyzed reaction for Kdn as well as for Neu5Ac, suggesting that the active site is common to the Neu5Ac and Kdn residues. Taken together, this sialidase is versatile and useful for the in vivo research on sialo-glycoconjugates. • Most bacterial sialidases fail to hydrolyze glycosides of a unique sialic acid Kdn. • A novel sialidase hydrolyzing Kdn residues is identified in genus Sphingobacterium. • The new sialidase is most versatile due to broad specificity and neutral optimum pH. [ABSTRACT FROM AUTHOR]

Electrochemical water splitting is one of the ways to produce environmentally‐friendly hydrogen energy. Transition‐metal (TM)‐based catalysts have been attracting attention due to their low cost and abundance, but their insufficient activity still remains a challenge. Here, 4 nm Mn3O4 nanoparticles (NPs) are successfully synthesized and their electrochemical behavior is investigated. Using electrokinetic analyses, an identical water oxidizing mechanism is demonstrated between the 4 and 8 nm Mn3O4 NPs. In addition, it is confirmed that the overall increase in the active surface area is strongly correlated with the superb catalytic activity of the 4 nm Mn3O4 NPs. To further enhance the oxygen evolution reaction (OER) performance, Ni foam substrate is introduced to maximize the entire number of the NPs participating in OER. The 4 nm Mn3O4/Ni foam electrode exhibits outstanding electrocatalytic activity for OER with overpotential of 395 mV at a current density of 10 mA cm−2 under neutral conditions (0.5 m PBS, pH 7). [ABSTRACT FROM AUTHOR]

A highly ionic‐conductive and high‐performance neutral pH polymer electrolyte comprises of Na2SO4 and polyacrylamide (PAM) was developed for solid electrochemical double‐layer capacitors (EDLCs). Na2SO4 was compared with Li2SO4 baseline in liquid electrolyte and exhibited higher ionic conductivity and identical stability window. Na2SO4−PAM electrolytes were optimized by varying their salt‐to‐polymer ratio. While all compositions show excellent stability for over 30‐day tracking period, an ionic conductivity of ca. 30 mS cm−1 was attained at 10,000 : 1 molar ratio of Na2SO4:PAM, among the highest reported for neutral pH polymer electrolytes. Raman spectroscopy verified that the electrolyte maintained well‐hydrated ions throughout the 30 days monitoring period. Solid EDLCs were constructed using activated carbon electrodes and Na2SO4−PAM electrolyte. They exhibited a wide 1.9 V operating window at 50 mV s−1 CV scan rate, with comparable capacitance to its liquid baseline. The solid EDLCs outperformed many symmetric devices in terms of energy and power densities. They also displayed good rate capability (up to 500 mV s−1) and excellent cycle life (>8,000 cycles). [ABSTRACT FROM AUTHOR]

This study investigated the application of a natural plant polyphenol, gallic acid (GA) to form complex with iron to promote the redox cycle of Fe(III)/Fe(II) under neutral initial pH conditions in the electrochemical (EC) system for activation of peroxymonosulfate (PMS) to efficiently degrade carbamazepine (CBZ). Results demonstrated that the synergistic effects of GA and EC significantly improved the removal efficiency, and the EC/GA/Fe(III)/PMS system effectively removed 100% of CBZ within a wide initial pH range of 3.0–7.0. The optimum stoichiometric ratio of GA to Fe(III) was found as 2:1. Investigations including quenching experiment, chemical probe analysis, and electron paramagnetic resonance (EPR) analysis were conducted to identify the primary reaction radicals as •OH, SO 4 •−, along with the 1O 2 and Fe(IV). In the EC/GA/Fe(III)/PMS system, the synergistic effect of GA and electrochemistry led to a remarkable enhancement in the generation of •OH. Furthermore, the complexation reduction mechanism of GA and Fe(III) was proposed based on experimental and instrumental analyses, which demonstrated that the semi-quinone products of GA were the main substances promoting the Fe(III)/Fe(II) cycle. Mass spectrometry results showed that CBZ generated 27 byproducts during degradation, with formic acid as the main product of GA. The degradation efficiency of the EC/GA/Fe(III)/PMS system remained stable and excellent, exhibiting remarkable performance in the presence of various inorganic anions, including Cl− and NO 3 −, as well as naturally occurring organic compounds such as fulvic acid (FA). Overall results indicated that the EC/GA/Fe(III)/PMS system can be applied to effectively treat practical wastewater treatment without requirement of pH adjustment. [Display omitted] • The EC/GA/Fe(III)/PMS system could efficiently remove CBZ at neutral pH condition. • Electro-synergistic GA significantly enhance the cycling of Fe(III)/Fe(III). • Electro-synergistic GA promoted the formation of •OH. • Chelation-reduction between GA and Fe(III) was examined under electric field. • The degradation pathways and byproducts of CBZ and GA were analyzed. [ABSTRACT FROM AUTHOR]