Cyclic Experiments Research Articles

Dendrite‐Free Zinc Anode for Zinc‐Based Batteries by Pre‐Deposition of a Cu–Zn Alloy Layer on Copper Surface via an In Situ Electrochemical Oxidation–Reduction Reaction

ABSTRACTThe prevention of uncontrollable growth of zinc dendrites on the zinc electrodes is one of the key challenges, hindering the widespread commercialization of zinc‐based energy storage technologies. Herein, we report a facile method to mitigate dendrite growth on a copper surface by an initial in situ coating of a Cu–Zn alloy layer, before zinc deposition. During further zinc deposition, the initially formed Cu–Zn alloy layer provides uniform nucleating sites and promotes homogeneous zinc deposition. A symmetrical cell, assembled using a Cu–Zn/Cu electrode could be stably cycled for over 1000 cycles in ZnSO4 solution, at a current density of 30 mA/cm2 and a coulombic efficiency of 99.9%. A zinc–air cell, assembled using Zn@Cu–Zn/Cu as the anode and rGO/Co3O4 composite as the cathode, exhibited a very stable performance at a high current density of 50 mA/cm2 and coulombic efficiency of ~93%, for over 400 cycles. After cycling experiments, the X‐ray photoelectron spectroscopy and the X‐ray diffraction analysis confirmed the formation of the Cu–Zn alloy layer. Hence, the present method provides an easy route for fabricating a dendrite‐free zinc electrode, for a wide range of zinc anode‐based batteries.

Characterising Cancer Cell Responses to Cyclic Hypoxia Using Mathematical Modelling

In vivo observations show that oxygen levels in tumours can fluctuate on fast and slow timescales. As a result, cancer cells can be periodically exposed to pathologically low oxygen levels; a phenomenon known as cyclic hypoxia. Yet, little is known about the response and adaptation of cancer cells to cyclic, rather than, constant hypoxia. Further, existing in vitro models of cyclic hypoxia fail to capture the complex and heterogeneous oxygen dynamics of tumours growing in vivo. Mathematical models can help to overcome current experimental limitations and, in so doing, offer new insights into the biology of tumour cyclic hypoxia by predicting cell responses to a wide range of cyclic dynamics. We develop an individual-based model to investigate how cell cycle progression and cell fate determination of cancer cells are altered following exposure to cyclic hypoxia. Our model can simulate standard in vitro experiments, such as clonogenic assays and cell cycle experiments, allowing for efficient screening of cell responses under a wide range of cyclic hypoxia conditions. Simulation results show that the same cell line can exhibit markedly different responses to cyclic hypoxia depending on the dynamics of the oxygen fluctuations. We also use our model to investigate the impact of changes to cell cycle checkpoint activation and damage repair on cell responses to cyclic hypoxia. Our simulations suggest that cyclic hypoxia can promote heterogeneity in cellular damage repair activity within vascular tumours.

Experimental study on the cyclic mineralization of CO2 enriched phase after absorption by a novel biphasic absorbent composed of DEEA and AEP.

The high energy consumption of Carbon Capture Utilization and Storage(CCUS) promotes the research of integrated absorption and mineralization technology. A novel DEEA/AEP biphasic absorbent is used to absorb [Formula: see text]. After phase separation, only one phase enriched with the absorption product is sent into the mineralization system, then reacts with [Formula: see text] to produce [Formula: see text] at normal temperature and pressure. The effects of temperature, Ca/C and dispersion of the system were investigated, and cyclic utilization experiment was also conducted. The process was characterized and analyzed by Thermal gravimetric analysis (TGA), X-ray diffraction (XRD), and nuclear magnetic resonance (13C NMR). The results showed that at 50 [Formula: see text]C, Ca/C = 1, the extent of mineralization of [Formula: see text]-enriched phase mineralization was 95.73% after ultrasonic treatment for 30 min. During 6 cycles, the volume percentage of [Formula: see text]-enriched phase could be maintained at 52-55%, and the [Formula: see text] load was 11.92mol/L. The results above indicate that the [Formula: see text]-enriched phase mineralization technology after absorption by biphasic absorbent can effectively capture [Formula: see text], realize recycling, and reduce CCUS energy consumption.

Fabrication of Two-Dimensional Bi2MoO6 Nanosheet-Decorated Bi2MoO6/Bi4O5Br2 Type II Heterojunction and the Enhanced Photocatalytic Degradation of Antibiotics

This article successfully synthesized a series of Bi2MoO6/Bi4O5Br2 heterojunctions using a two-step solvothermal method followed by calcination, and the photocatalytic activity by degradation of tetracycline hydrochloride (TC) was investigated. Compared with pure Bi4O5Br2 and Bi2MoO6, a series of Bi2MoO6/Bi4O5Br2 heterojunctions exhibit higher photocatalytic activity, which can be attributed to the heterostructures with strong interfacial interaction, improving the charge separation. The 2% Bi2MoO6/Bi4O5Br2 heterojunction shows the best photocatalytic activity under visible light irradiation, which is 1.9 times and 1.8 times that of Bi2MoO6 and Bi4O5Br2, respectively. In addition, cyclic experiments have shown that 2% Bi2MoO6/Bi4O5Br2 heterojunction has high stability, with a degradation efficiency only decreasing by 3% after 5 cycles. From the capture agent experiment and ESR test, it can be seen that ·O2− and h+ are the main active species. A possible photocatalytic mechanism of 2% Bi2MoO6/Bi4O5Br2 heterojunction under visible light irradiation was proposed.

The degradation of Sulfamethoxazole using a heterojunction photocatalytic membrane composed of Z-scheme LaFeO3/Ag3PO4@GO: Assessment of activity and degradation mechanisms

We synthesized La-deficient LaFeO3 through a simple hydrothermal method, enhancing the physicochemical properties and catalytic performance of the initial LaFeO3. Subsequently, Ag3PO4 was grown on 0.7 LaFeO3 using electrostatic deposition to obtain composite materials LA-1, LA-2, and LA-3 with different composite ratios, improving the transfer rate of photogenerated charge carriers and reducing impedance. By physically combining LA with GO, a photocatalytic membrane LAG was produced, effectively enhancing the stability and recyclability of the photocatalytic membrane. The photocatalytic membrane LAG-2 achieved an 80.4% SMX degradation efficiency under neutral conditions, with a degradation rate of 76.5% at pH=3. The retention rate for SMX was 82%, with a flux of 106.2L·m-2 h-1 bar-1. Additionally, the flux for CIP reached 530.8L·m-2 h-1 bar-1, with a retention rate of 65.5%. After six cycling experiments, the degradation rate of LAG-2 was 67.4%, and the leaching concentration of iron ions exhibited good performance. SEM analysis reveals that the morphology of the membrane remains intact before and after the cycle, with LAG retaining its integrity and exhibiting excellent mechanical properties. This indicates that the photocatalytic membrane demonstrates good stability and reusability. The excellent integration of the photocatalyst and membrane overcomes the challenge of difficult recovery of the photocatalyst, promising extensive applications and providing new insights for the practical application of photocatalytic degradation of antibiotics.

Scale‐ and Variable‐Dependent Localization for 3DEnVar Data Assimilation in the Rapid Refresh Forecast System

AbstractThis study demonstrates the advantages of scale‐ and variable‐dependent localization (SDL and VDL) on three‐dimensional ensemble variational data assimilation of the hourly‐updated high‐resolution regional forecast system, the Rapid Refresh Forecast System (RRFS). SDL and VDL apply different localization radii for each spatial scale and variable, respectively, by extended control vectors. Single‐observation assimilation tests and cycling experiments with RRFS indicated that SDL can enlarge the localization radius without increasing the sampling error caused by the small ensemble size and decreased associated imbalance of the analysis field, which was effective at decreasing the bias of temperature and humidity forecasts. Moreover, simultaneous assimilation of conventional and radar reflectivity data with VDL, where a smaller localization radius was applied only for hydrometeors and vertical wind, improved precipitation forecasts without introducing noisy analysis increments. Statistical verification showed that these impacts contributed to forecast error reduction, especially for low‐level temperature and heavy precipitation.

Construction and degradation mechanism of the magnetic CoFe1.95Y0.05O4/Ag/g-C3N4 Z-scheme heterojunction for enhanced photocatalytic activity

In this study, a Z-scheme heterojunction CoFe1.95Y0.05O4/Ag/g-C3N4 (CFYO/ACN) magnetic nanocomposite was prepared by hydrothermal synthesis. The composite was characterised and analysed using different characterisation tools and its photocatalytic degradation activity towards methylene blue (MB) was investigated. The results showed that the CFYO/ACN photocatalyst compared to CoFe1.95Y0.05O4 (CFYO) and Ag/g-C3N4 (ACN), the composite CFYO/ACN had the highest degradation efficiency of MB, which was up to 97% within 120 min, which was 1.26 and 1.09 times higher than that of ACN and CFYO, respectively. The enhancement of the catalytic performance of CFYO/ACN was attributed to the fact that the heterogeneous junction formation effectively inhibited the complexation of photogenerated carriers. In addition, five consecutive cyclic degradation experiments showed that CFYO/ACN exhibited efficient photocatalytic degradation, stable crystal structure, and easy recycling in the photodegradation process. Finally, the capture experiments confirmed that superoxide radicals () and hydroxyl radicals (·OH) play a major role in the degradation process. This study provides an effective strategy for the construction of efficient photocatalysts.

Permanent deformation and particle crushability of calcareous sands under cyclic traffic-induced loadings through simple shear apparatus

This study focuses on investigating permanent deformations, encompassing normal and shear strains, of calcareous sandy soils subjected to drained cyclic traffic-induced loadings. The investigation utilizes a Simple Shear (SS) apparatus allowing for variations in both normal and shear stress components over each cycle and incorporates Principal Stress Rotation (PSR), a feature not replicable in conventional cyclic uniaxial triaxial tests which is the key aspect of this research. The study also accounts for the harmonically changing the effective horizontal stress resulting from cyclic variations of effective vertical stress, conducted under a horizontally constrained boundary condition with zero lateral strain. A series of drained cyclic simple shear experiments is carried out, implementing a heart-shaped stress path, encompassing up to 1000 cycles. The objective of the study is to analyze permanent normal and shear deformations, along with associated total particle crushing, using both sieving analyses and 2D image processing of particles. The study also evaluates the impact of an initial static shear stress originating from the longitudinal slope of roads. The findings highlight the influences of induced cyclic amplitudes of stress components, principal stress and strain rate rotation, and initial static shear stress on the development of permanent strains. Furthermore, the research characterizes particle crushability in terms of total crushability over such loading, examining its dependency on relative density and variations in both shear and normal stress components.

Basic Study on the Proposal of New Measures to Improve the Ductility of RC Bridge Pier and Their Effectiveness

To enhance the seismic performance of reinforced concrete (RC) elements, it is essential to consider both strength and ductility post-yielding. This study proposed a novel method to improve the ductility of RC piers by using preformed inward-bending longitudinal reinforcements at the plastic hinges. Two full-scale model tests of standard and ductility-enhanced (DE) RC piers and numerical simulations were conducted. The lateral reversed cyclic loading experiments were conducted to assess the effectiveness of this new approach. The performance was evaluated regarding failure mode, plastic hinge distribution, hysteretic properties, normalized stiffness degradation, normalized energy dissipation capacity, bearing capacity, and ductility. Non-linear finite element method (FEM) analyses were also carried out to investigate the usefulness of the proposed method by DIANA, and simulation was validated against the experiment results by hysteretic curves, skeleton curves, failure mode crack pattern, ductility coefficient, and bearing capacity. The results indicated that the proposed method enhanced bearing capacity, resistance to stiffness degradation, energy dissipation capacity, and ductility. Additionally, it was observed that the preformed positions and curvature of the main steel bars influenced the plastic hinge location and the buckling of longitudinal reinforcements. FEM analysis revealed that it might be reasonable to deduce the other factors that influenced the ductility of the specimens by using the same material parameters and models.

Visible light degradation of antibiotics catalyzed by nanoporous carbon/V2O5 nanocomposite: structural, optical and electrochemical properties

In this study, nanoporous carbon (NPC) decorated V2O5 (NPC/V2O5) nanocomposite synthesized by a hydrothermal technique using biomass-derived NPC nanoflakes towards the application of berberine hydrochloride (BH) dye degradation under visible light irradiation. The prepared samples were characterized by X-ray Diffraction (XRD), Raman spectroscopy, Field Emission Scanning Electron Microscopy (FE-SEM), Transmission Electron Microscopy (TEM), Energy-Dispersive X-ray (EDX), UV-Visible and Photoluminescence (PL) spectroscopy. Charge transfer resistance was measured by electrochemical impedance spectroscopy (EIS) and liner sweep voltammetry (LSV). XRD studies confirm the orthorhombic crystal structure of NPC/V2O5 nanocomposite. FE-SEM and TEM analysis validate their particle-like and sheet-like morphology of V2O5 and NPC respectively. Further, UV-visible DRS and PL spectra of the green synthesized NPC/V2O5 nanocomposite exhibited a low band-gap and reduced recombination rate compared to the pure counterpart which is better light-absorbing ability in the visible light region. Batch experiments represent the incorporation of NPC and V2O5 would lead to an increase the photocatalytic performance of NPC/V2O5 toward BH dye degradation. During the photocatalytic reaction, the NPC/V2O5 nanocomposite degraded rate around 97.7% against BH dye within 80 min while pure V2O5 degraded 92.5% of BH dye under same visible light irradiation time. Finally, the cyclic stability experiment exhibits the photocatalyst even stable after five consecutive tests.

Constructing stable solid electrolyte interphases to enhance the calendar life of anode-free lithium metal batteries

Advancement of anode-free lithium metal batteries (AFLMBs) has been appreciated due to their exceptional volumetric energy density and manufacturing simplicity. However, AFLMBs suffer from poor cycle performance due to the absence of excess lithium and current research lacks an understanding of lithium corrosion and calendar aging in AFLMBs. Here, we investigate the practical effects of chemical and galvanic corrosion on battery performance (calendar life) through a modified full-cell cycling experiment. The impact of galvanic corrosion is negligible, whereas chemical corrosion during a rest period reduces the capacity retention (CR) from 47% to 32% over 100 cycles. Consequently, a corrosion control strategy is implemented, substituting 1,2-dimethoxyethane with 1,2-dimethoxypropane (DMP), which has weaker lithium ion solvation properties due to its inductive effect. This approach results in the formation of a Li2O-rich solid-electrolyte interphase (SEI) layer, which effectively prevents direct contact of lithium with the electrolyte and the formation of additional SEI layers. Consequently, the decrease in CR due to chemical corrosion is considerably mitigated in DMP-based electrolyte, with only a slight decrease from 51% to 49%. This study provides insights into lithium corrosion in practical AFLMBs and offers guidelines for designing less-corrosive electrolytes to improve AFLMB performance for diverse industrial applications as energy-storage devices.

Mn-Zr promoted CaCO3 porous microspheres for enhanced performance in direct solar-driven calcium looping

The Calcium looping thermochemical reaction directly driven by solar energy effectively addresses the problem of efficient energy storage of concentrated solar power plants (CSP) by shortening the energy conversion path. But new requirements are put forward for energy storage materials, including high solar radiation absorption, high cycling stability and fast kinetics. To meet these challenges, we have designed porous microsphere structures for the purpose of enhancing mass transfer and the capture of solar radiation. Additionally, Zr and Mn oxides with elevated Tammann temperatures were incorporated to stabilize the morphology and prevent sintering. The synthesized porous microspheres retained abundant mesoporous channels on the surface even after undergoing 20 cycles. The addition of Mn oxide significantly enhances solar spectral absorptivity, achieving an impressive 82.88 % absorbance. The incorporation of Mn and Zr oxides increased the sintering resistance, specific surface area and porosity of CaO/CaCO3, especially in the 10–100 nm range, which accelerated the CO2 transport during carbonation. These enhancements significantly improve the chemical control stage of the carbonation reaction, as further supported by kinetic models. After 50 cycle experiments at 800 °C, the energy storage density of the sample remains at 1074 kJ/kg, which is 1.86 times that of the undoped CaCO3. This study provides a new way to design CaCO3 materials suitable for CSP applications.

MXene/TiO2 NAs on CC flexible electrode for electrocatalytic tigecycline degradation: Performance, Mechanistic insights, and toxicological assessment

In this study, a composite electrode (MXene/TiO2 NAs@CC) based on TiO2 nanotube arrays (NAs) and two-dimensional MXene-coated carbon cloth (CC) was prepared. The electrode greatly improved the catalytic activity by capturing protons through the abundant active sites of TiO2 nanotube arrays and promoting proton reduction with the high conductivity of MXene. Moreover, the composite electrode possessed the largest specific surface area (9.1660 m2·g−1) according to the results of the BET test. Under optimal conditions, the composite electrode degraded tigecycline (TGC) up to 86.66 % in 20 min. Furthermore, the electrocatalytic performance was not affected after 10 cycling experiments and 60 days of exposure to air, indicating its excellent stability. In addition, the cathodic co-catalytic reaction mechanism involving anode ·OH, HClO, and cathode H* was proposed. The degradation pathways of TGC and the toxicity of possible intermediates were also analyzed. Finally, a two-stage continuous wastewater reactor with high efficiency and low consumption (90.46 % removal rate, 0.061 kWh/m3) was designed. This study provides a new idea for designing an electrocatalytic reactor with high efficiency, stability, and low consumption, enriching the field of electrocatalytic treatment strategies for antibiotic wastewater. It is of great significance for the protection of the water environment and human health.

Highly efficient CO2 capture by a non-aqueous amine-based absorbent of 3 aminopropanol/polyethylene glycol 200: Experimental and computational simulation

In the present work, a novel non-aqueous 3-aminopropanol/polyethylene glycol 200 (3AP/PEG200) absorbent for efficient carbon dioxide (CO2) capture was designed using environment-benign and non-toxic polyethylene glycol 200 (PEG200) as an alternative to water. The mechanism, physical, thermodynamic, and kinetic properties of absorption process was investigated through a combination of experimental and multi-scale computational simulation approaches including molecular dynamics (MD) simulation and quantum chemical (QC) calculations. It was found that the addition of PEG200 not only enhanced the thermal stability of the absorbent, but also did not significantly increase the viscosity. In addition, kinetic studies revealed that the absorption process conforms to a pseudo-first-order equation, with the activation energy (Ea) value of 20.40 kJ/mol, significantly lower than that of the benchmark 30 % monoethanolamine (MEA) aqueous solution used in industrial CO2 capture. Furthermore, the enthalpy change (ΔH) and entropy change (ΔS) values were found to be more negative than those of other liquid absorption systems, indicating that the 3AP/PEG200 absorbent is favorable for CO2 absorption even at low partial pressures. Most importantly, the absorption system exhibited good regeneration capability, as demonstrated by five absorption–desorption cycle experiments. In conclusion, the non-aqueous 3AP/PEG200 absorbent exhibits low viscosity, high thermal stability, enhanced absorption capacity, and excellent cyclic performance, positioning it as a promising candidate for CO2 absorption in industrial applications.

A highly water-soluble phenoxazine quaternary ammonium compound catholyte for pH-neutral aqueous organic redox flow batteries

The pH-neutral aqueous redox flow battery (ARFB) is one of the most attractive flow batteries due to its non-corrosiveness, low-cost, and wider electrochemical stability window compared to those with acidic or alkaline electrolytes. However, there are few families of organic redox-active molecules available as catholyte materials for pH-neutral ARFBs. Herein, through incorporation of quaternary ammonium moiety into the redox-active phenoxazine nucleus, an organic catholyte material, N, N, N-trimethyl-2-(10H-phenoxazin-10-yl) ethan-1-aminium chloride (NEt-POZ) is achieved for pH-neutral ARFBs. The NEt-POZ has a high redox potential of 0.79 V versus SHE and rapid redox kinetics (0.23 cm s−1) as well as high water-solubility (∼2.6 M in H2O). Paired with a methyl viologen (MV) anolyte in the pH-neutral aqueous electrolyte, a viologen-phenoxazine ARFB full cell is assembled, which shows an open circuit voltage of ∼1.23 V. However, the results of long-term cycling experiments indicate low Coulomb efficiency and rapid declining capacity of the NEt-POZ catholyte. The mechanism analysis unveils that the unstable doubly oxidized tri-cations (NEt-POZ3+) formed via the disproportionation of radical di-cations (NEt-POZ2+) in solution readily react with chloride anions to form poly-chlorinated derivatives, which precipitate from the catholyte due to their poor water solubility, leading to a rapid decrease in capacity. When there is no chloride present in the electrolyte solution, highly reactive NEt-POZ3+ cations can interact with other counter-anions (such as sulfate and carbonate ions) and even water to form complex adducts.

2D MXene nanosheet dispersed Mn, Ru NPs loaded Ti composite electrodes for electrocatalytic synergistic degradation of antibiotics in high-salt mariculture wastewater

In this study, a composite electrode based on etched TiO2 nanotube arrays and two-dimensional (2D) MXene nanosheets was successfully designed for efficient degradation of antibiotics in mariculture wastewater. The composite electrode effectively dispersed Mn and Ru nanoparticles (NPs) by introducing 2D MXene nanosheets as an intermediate layer, which significantly enhanced the catalytic performance. The bifunctional properties of Mn and Ru NPs in catalysis and the contribution of d-orbital electrons to the formation of metal‑hydrogen bonds were revealed in depth by analyzing the electron transfer mechanism at the electrodes. The experimental results demonstrated a synergistic catalytic effect between Mn and Ru bimetals and MXene, resulting in an effective increase in the degradation rate. Under the optimal conditions, the degradation rate of Tetracycline (TC) by Mn/Ru/MXene/Ti composite electrode could reach 90.69 % in 60 min. In addition, it still shows excellent stability after 45 days of air exposure, 10 cycling experiments, and 10,000 s of timed current testing. Mechanistic studies have demonstrated that anode hydroxyl radical (·OH), HClO, and cathode activated hydrogen atoms (H*) all play catalytic roles in the degradation process. The degradation pathways were analyzed using density-functional theory (DFT) calculations and liquid-liquid-mass spectrometry (LC-MS) techniques, with further experiments confirming that this degradation process effectively reduces the biotoxicity of intermediate products, improving the safety of wastewater discharge. Finally, we designed the reactor and calculated the energy consumption to verify the feasibility and economy of the system in practical applications. This research proposes a novel multi-metal co-catalysis and cathode and anode co-catalysis system for the efficient degradation of antibiotics in mariculture wastewater, with potential applications in the electrocatalytic degradation of antibiotics.

Mechanical properties of diamond-type triply periodic minimal surface structures fabricated by photo-curing 3D printing

Triply periodic minimal surface (TPMS) structures have attracted significant attention owing to their smooth surface configuration and parametric modeling properties. In this study, photo-curing 3D printing was employed to generate diamond-type TPMS structures, and micro-CT scanning revealed the presence of internal defects within the 3D printed TPMS structures. Two key design variables were explored: volume fraction and unit cell size. Quasi-static compression experiments were conducted to delve into the compression properties and energy absorption capabilities of the 3D printed TPMS structures. The findings reveal that increasing the volume fraction significantly enhances the compressive modulus, ultimate strength, and energy absorption capacity of TPMS structures. Additionally, increasing the cell size improves compression properties and energy absorption per unit volume. To predict the coupling effect of volume fraction and unit cell size on the compression performance of TPMS structures, a bivariate quadratic regression model was established. In addition, TPMS structures were subjected to load-unload cyclic experiments, shedding light on the evolution patterns of residual strain and hysteresis energy during cyclic loading. It provides insights into the design of reusable and fatigue-resistant diamond-type TPMS structures for various engineering applications.

High‐Temperature Oxidation Response of 444 Ferritic Stainless Steel in a Synthetic Automotive Exhaust Gas

The high‐temperature oxidation behavior of 444 ferritic stainless steel has been studied in cyclic oxidation experiments using synthetic automotive exhaust gas atmospheres at 950 and 1050 °C. The weight gain per unit area of the 444 ferritic stainless steel following oxidation at 950 °C for 100 h iss 85.7% lower than recorded at 1050 °C. The oxide scale at both temperatures consisted of Fe–Cr and Mn–Cr spinels in the outer layer and Cr2O3 in the inner layer. Nodule formation and spallation of the oxide scale are identified as the main causes of breakaway oxidation. The depth of the internal oxides gradually increases with the oxidation time. The nucleation and growth of internal SiO2 result in the formation of metal protrusions, which are eventually consumed in the formation of a SiO2 layer. The SiO2 layer is formed at the interface between the oxide scale and the substrate at 1050 °C. The nucleation and growth of internal SiO2, in combination with lateral growth of SiO2 at the Cr2O3 layer/substrate interface contributed to the formation of the SiO2 layer.

An Isoniazid-Based reversible Schiff base chemosensor for Multi-Analyte (Cu2+, Ni2+, Hg2+) detection

Isoniazid-based Schiff base N’-(furan-2-ylmethylene)isonicotinohydrazide (FINH) has been synthesized. FINH has proven its ability to selectively sense and respond to Cu2+, Ni2+, and Hg2+, which shows its potential as a chemosensor. UV–visible experiments, the absorption band (at 360 nm) of FINH shifted with the gradual addition of Cu2+, Ni2+, and Hg2+. A significant quenching in the emission band of FINH in fluorescence spectra has been observed with the addition of analytes at the physiological pH range. Cyclic voltammetric experiments have been conducted to determine the electron transfer process that occurs during the complexation of FINH with analytes. Moreover, the interactions of FINH-metal ions are reversible, and their reversible behavior has been demonstrated with the Na2EDTA solution. The binding insights among FINH and Cu2+, Ni2+, and Hg2+ are explained by IR spectral study. Additionally, the FINH works within the appreciable detection limit of 9.472 x 10−7 M (for Cu2+), 7.685 x 10−7 M (for Ni2+) and 2.411 x 10−7 M (for Hg2+), limit of quantitation of 3.15 x 10−6 M (for Cu2+), 2.561 x 10−6 M (for Ni2+) and 8.036 x 10−7 M (for Hg2+). Applying this isoniazid-based reversible chemosensor in analyzing real samples demonstrates its practicality and effectiveness for multi-analyte detection. This sensor could consistently measure metal ion concentrations in various environmental and biological samples, providing a valuable tool for monitoring pollutants and evaluating exposure risks.

Enhancing Organic Pollutant Degradation Efficiency through a Photocatalysis-Electro-Fenton System via MoS2 Crystal Morphology Regulation.

A photocatalysis-electro-Fenton (PEF) system was constructed via molybdenum disulfide (MoS2) to remove tetracycline (TC) without an external oxidant supply and solution pH adjustment. In the system, original graphite felt (GF) was used as a cathode, from which H2O2 was in situ generated continuously under power. MoS2 was motivated by visible light to facilitate the cycle of Fe2+/Fe3+, enhancing the Fenton process to produce •OH. The experimental results showed that the system can increase the degradation rate of pollutants by more than 5 times. Moreover, the quenching and electron paramagnetic resonance (EPR) tests demonstrated that •OH was the dominant active species. X-ray photoelectron spectroscopy (XPS) characterization, Mo concentration, and cycle experiments proved the excellent catalytic activity and chemical stability of MoS2. It is worth mentioning that the photocatalytic performances of different morphologies of MoS2 (flower, flake, and radar) were compared. As a result, flower-like MoS2 exhibited a much superior photoresponse than flake and radar, which could accelerate the Fe2+/Fe3+ cycle further effectively. These findings highlight the morphology-performance relationship of MoS2 under a PEF system and the mechanisms of contaminant degradation, which is of great significance for developing photoelectric Fenton technology.