Aqueous Sulfate Research Articles

Interfacially self-assembled Fe2O3 nanoparticles decorated kaolinite for high performance anti-bacterial and anti-cancerous agents

Nano-engineering of naturally occurring layered materials incorporates enhanced inherent properties for bionanotechnology. Here, kaolinite was treated with a concentrated aqueous ferrous sulfate solution at 100 °C for 1 h for surface modification. Therefore, interfacially self-assembled nanostructure of ferric oxide (Fe2O3) decorated kaolinite composites (FDKC) was fabricated from cationically (Fe2+) modified kaolinite (CMK) after calcinations at 680 °C. Characterized nanocomposites by ATR-IR, EDS, XRD and SEM were tested for antimicrobial activity and antibiofilm activity against Gram negative bacteria Escherichia coli (E. coli), Klebsiella spp (K. spp) and Salmonella typhi (S typhi), as well as Gram positive Staphylococcus aureus, while cytotoxic activity was observed against HeLa cell. CMK and FDKC showed significantly higher antimicrobial activity and biofilm destruction ability than virgin kaolinite (p < 0.05). Besides, FDKC showed the highest anticancer activity in HeLa cell at moderate concentration. The synergistic effect of nanocomposites would offer the modulation of enhanced electronic and physical properties from a simple technology to improve inherent antimicrobial activity and cell toxicity of kaolinite for targeted assay.

Osmotic and Activity Coefficients of Aqueous Lithium Sulfate Solutions within the Temperature Range 293.15–498.15 K to 40 MPa

Osmotic and Activity Coefficients of Aqueous Lithium Sulfate Solutions within the Temperature Range 293.15–498.15 K to 40 MPa

Zinc-ion hybrid supercapacitors with hierarchically N-doped porous carbon electrodes and ZnSO4/ZnI2 redox electrolyte exhibit boosted energy density

Zinc-ion hybrid capacitors (ZIHCs) with high energy density is commercial need as energy storing devices, but facile preparation is still a challenge. Herein, we proposed a combined strategy for preparation of ZIHCs with high performance. For this purpose, a nanoemulsion assembly approach with Pluronic F127 as structure-directing agent, 1, 3, 5-trimethylbenzene as pore-expanding agent, polydopamine as carbon and nitrogen source, was used to synthesize hierarchically N-doped porous carbon spheres (N-HNCSs). The optimized sample of N-HNCS-1 exhibited uniform size of 150 nm, hierarchically porous structure, large surface area (705.46 m2 g−1), and N-doping amount of 6.51 %. These properties were beneficial for the transportation of the electrolyte ions resulted in that the N-HNCS-1 electrode displayed superior electrochemical performance with specific capacity of 142 mAh g−1. Furthermore, the Zn//ZnSO4 + ZnI2//N-HNCS-1 ZIHCs achieves an exceptionally high energy density of 347.7 Wh kg−1, which is 3-fold higher than that of Zn//ZnSO4//N-HNCS-1 ZIHCs. To elucidate this outstanding performance, we investigate the mechanisms involved, including Zn2+ deposition/stripping, SO42-/I- adsorption/desorption, Zn4SO4(OH)6⋅0.5 H2O precipitation/dissolution, and redox reactions relating to iodine ions. The incorporation of ZnI2 redox-electrolyte significantly enhanced the energy density by providing prominent pseudocapacitance via the faradaic reaction. Therefore, the high performance of Zn//ZnSO4 + ZnI2//N-HNCS-1 ZIHCs is attributed to the introduction of nitrogen (N) species, advantageous 3D carbonaceous framework, and redox reactions triggered by adding zinc iodide (ZnI2) into the aqueous zinc sulfate (ZnSO4) electrolyte. This groundbreaking research opens up possibilities for the development of high-energy ZIHCs, and advancements in energy storage technology.

Supercapacitor Performance of MXene-Coated Carbon Nanofiber Electrodes

MXenes consisting of thin layers of transition metal carbides or nitrides are good candidates for electrode materials due to their excellent electrical conductivity and fast ion transfer. Electrospun carbon nanofibers are highly porous and electrically conductive, making them attractive for electrode materials. In this study, free-standing electrodes were prepared by the dip-coating of carbon nanofibers (CNFs) in the MXene (Ti3C2) colloidal solution, which was synthesized via the wet-etching of MAX (Ti3AlC2) phase, and their chemical structures were investigated by X-ray diffraction and Fourier transform infrared spectroscopy. In addition, scanning and transmission electron microscopy were used to investigate the morphological and crystallographic features of MXene-coated CNFs. Surface area and pore volumes were investigated by nitrogen adsorption/desorption measurements. Supercapacitor performance was studied by assembling a 3-electrode system with 1M aqueous sodium sulfate solution as an electrolyte. MXene-coated CNFs exhibited a maximum specific capacitance of 514 F/g at 0.5 A/g, with energy and power densities of 71.4 Wh/kg at 0.5 A/g and 2.3 kW/kg at 5 A/g, respectively, which are relevantly higher compared to the pristine CNFs due to the pseudocapacitive behavior of MXenes. They also showed comparable cyclic stability during 5000 cycles with the CNFs. This result indicates that MXene-coated carbon nanofibers can be effective electrode materials for electrochemical energy storage.

Evaluating the role of nitrogen in carbon hosts for aqueous zinc sulfur batteries

Evaluating the role of nitrogen in carbon hosts for aqueous zinc sulfur batteries

Ionic liquid as a cosurfactant for critical heat flux enhancement during boiling with aqueous surfactant solutions

Surfactants are often used to improve boiling heat transfer due to the ease of their implementation. While aqueous surfactant solution significantly increases the heat transfer coefficient (HTC), it is known to deteriorate the critical heat flux (CHF) relative to the base fluid water. The high foamability of most surfactant solutions causes vapor crowding on the heater surface, making surface modification techniques ineffective for CHF enhancement. Here, we address the issue of relative degradation of CHF due to surfactant by using an ionic liquid as a cosurfactant. We employ a unique boiling fluid, where 1-ethyl-3-methylimidazolium chloride ([C2mim][Cl]), a low-foaming ionic liquid, is introduced as a co-surfactant in aqueous sodium dodecyl sulfate (SDS) solution. Motivated by the synergistic increase in foamability of the aqueous surfactant solution due to the addition of ionic liquid, we examine the boiling performance at various combinations of concentrations of the two additives in the solution. The mixture consistently exhibits higher CHF and HTC than an SDS only solution, with the best enhancement observed for a mixture of ≈ 30 ppm SDS and ≈ 750 ppm [C2mim][Cl], resulting in ≈1.6× and ≈1.5× enhancements in CHF and HTC, respectively, compared to the SDS only solution (≈ 30 ppm). We next fine-tune the concentration of cosurfactant to demonstrate an exceptionally high HTC of ≈93 kW/(m2 – ℃) with a CHF value comparable to that of pure water. Enhanced foamability and in-situ improvement in the wettability of the heater surface enhance the HTC and the CHF, respectively. This facile technique for enhancing HTC with water as the base fluid, without compromising on CHF, holds promise for high heat flux thermal management applications.

Water activity and surface tension of aqueous ammonium sulfate and D-glucose aerosol nanoparticles

Abstract. Water activity (aw) and interfacial energy or surface tension (σ) are key thermodynamic parameters to describe the hygroscopic growth of atmospheric aerosol particles and their ability to serve as cloud condensation nuclei (CCN), thus influencing the hydrological cycle and climate. Due to size effects and complex mixing states, however, these parameters are not well constrained for nanoparticles composed of organic and inorganic compounds in aqueous solution. In this study, we determined aw and σ by differential Köhler analysis (DKA) of hygroscopic growth measurement data for aerosol particles smaller than 100 nm composed of aqueous ammonium sulfate (AS), D-glucose (Gl), and their mixtures. High-precision measurements of hygroscopic growth were performed at relative humidities (denoted RH) ranging from 2.0 % to 99.6 % with a high-humidity tandem differential mobility analyzer (HHTDMA) in three complementary modes of operation: hydration, dehydration, and restructuring. The restructuring mode (hydration followed by dehydration) enabled the transformation of initially irregular particles into compact globules and the determination of mass equivalent diameters. The HHTDMA-derived growth factors complemented by DKA allows for determination of water activity and surface tension from dilute to highly supersaturated aqueous solutions that are not accessible with other methods. Thus, for mixed AS / Gl nanoparticles with mass ratios of 4:1 and 1:1, the upper limit of solute mass fraction (Xs) was 0.92 and 0.98, respectively. For pure AS and Gl, the DKA-derived aw is in good agreement with electrodynamic balance and bulk measurement data. For AS particles, our aw data also agree well with the Extended Aerosol Inorganics Model (E-AIM III) over the entire concentration range. In contrast, the UNIFAC model as a part of AIOMFAC (Zuend et al., 2011) was found to overestimate aw in aqueous Gl particles, which can be attributed to unaccounted intermolecular interactions. For mixed AS and Gl nanoparticles, we observed a non-monotonic concentration dependence of the surface tension that does not follow the predictions by modeling approaches constructed for mixed inorganic/organic systems. Thus, AS / Gl particles with a 1:1 mass ratio exhibited a strong decrease of σ with increasing solute mass fraction, a minimum value of 56.5 mN m−1 at Xs≈0.5, and a reverse trend of increasing σ at higher concentrations. We suggest that D-glucose molecules surrounded by ammonium sulfate ions tend to associate, forming non-polar aggregates, which lowers the surface tension at the air–droplet interface. We analyzed the uncertainty in the DKA-derived water activity and surface tension, related to the instrumental errors as well as to the morphology of the nanoparticles and their phase state. Our studies have shown that under optimal modes of operation of HHTDMA for moderate aqueous concentrations, the uncertainty in aw and σ does not exceed 0.2 %–0.4 % and 3 %–4 %, respectively, but it increases by an order of magnitude in the case of highly concentrated nanodroplet solutions.

Organic electrochemical transistors for monitoring dissolved oxygen in aqueous electrolytes of zinc ion batteries

Dissolved oxygen (DO) in the electrolyte of aqueous zinc ion batteries (AZIBs) can cause irreversible side reactions in zinc metal anode. Therefore, the accurate detection of the DO concentration in the aqueous electrolyte is crucial for the performance promotion and mechanistic studies of AZIBs. Herein, organic electrochemical transistor (OECT) based DO sensors are developed by utilizing a carbon fiber (CF) derived CF/platinum/Nafion/polydimethylsiloxane composite as the gate electrode and amine-doped poly(3,4-ethylenedioxythiophene): polystyrene sulfonate as the channel semiconductor. Operating at a gate-source voltage of −0.1 V and a drain-source voltage of −0.025 V, the OECT-DO sensor demonstrates a high sensitivity (141 mV decade−1), a low detection limit (0.0011 mg L−1), a wide linear range (0.027–8.7 mg L−1), and good stability, which are attributed to the transconductance capability of OECT. The exceptional performance of the OECT-DO sensor enables the accurate monitoring of DO content in aqueous zinc sulfate electrolyte, which provides an opportunity to gain an insight of the impact of DO concentration on the zinc metal electrode. This study not only provides a cost-effective and efficient solution for detecting DO concentration in aqueous electrolytes, but also explores the potential applications of OECT sensors in the energy storage devices.

Direct recovery of electro-synthesized ammonia from low-concentration nitric oxide using pulse electrodeposited Cu/C catalyst in a catholyte-free system

Electrochemical production of ammonia (NH3) from nitric oxide (NO) offers a sustainable and environmentally friendly way to convert a nitrogenous pollutant into a valuable chemical feedstock and energy carrier. However, practical challenges in the electrochemical NO-to-NH3 conversion stem from mass transport limitations due to low NO concentrations in real-world streams and the need for post-purification of synthesized NH3. In this study, by synergistically developing an electrocatalyst (pulse-electrodeposited copper) and implementing a catholyte-free cell configuration with advantages of (i) facile NO transport, (ii) inhibited side reaction, and (iii) direct NH3 recovery in an external acid, we showcase an NH3 Faradaic efficiency of 85.6 % and a production rate of 53.4 μmol cm−2h−1 starting from 500 ppm NO. Crucially, the electro-synthesized NH3 was directly recovered as a high-purity aqueous ammonium sulfate solution comparable to industrial-grade quality. This approach opens the door to transforming waste into resources in a more energy-efficient and straightforward manner.

Impact of acidity and surface-modulated acid dissociation on cloud response to organic aerosol

Abstract. Acid dissociation of the organic aerosol fraction has the potential to impact cloud-activating properties by altering aqueous-phase H+ concentrations and water activity but is currently overlooked in most atmospheric aerosol models. We implemented a simple representation of organic acid dissociation in the aerosol–chemistry–climate box model ECHAM6.3–HAM2.3 and investigated the impact on aerosol-forming aqueous sulfur chemistry, cloud droplet number concentrations, and the shortwave radiative effect. Many atmospheric organic acids are also surface-active and may be strongly adsorbed at the surface of small aqueous droplets. The degree of dissociation has recently been observed for several atmospheric surface-active organics with Brönsted acid character to be significantly shifted in the surface, compared to the bulk aqueous solution. In addition to the well-known bulk acidity, we therefore introduced an empirical account of this surface-modulated dissociation to further explore the potential impact on aerosol climate effects. Malonic acid and decanoic acid were used as proxies for atmospheric organic aerosols of different surface-active and acid strengths. Both acids were found to yield sufficient hydrogen ion concentrations from dissociation in an aqueous droplet population to strongly influence aqueous aerosol sulfur chemistry, leading to enhanced cloud droplet number concentrations and a cooling shortwave radiative effect. Further considering the surface modulation of organic acid dissociation, the impact on cloud microphysics was smaller than according to the well-known bulk solution acidity but still significant. Our results show that organic aerosol acid dissociation can significantly influence predictions of aerosol and cloud droplet formation and aerosol–cloud–climate effects and that, even for a well-known bulk solution phenomenon such as acidity, it may be important to also consider the specific influence of surface effects when surface-active acids comprise a significant fraction of the total organic aerosol mass.

Less is More: Underlying Mechanism of Zn Electrode Long-Term Stability using Sodium L-Ascorbate as Electrolyte Additive.

Structured passivation layers and hydrated Zn2+ solvation structure strongly influence Zn depositions on Zn electrodes and then the cycle life and electrochemical performance of aqueous zinc ion batteries. To achieve these, the electrolyte additive of sodium L-ascorbate (Ass) is introduced into aqueous zinc sulfate (ZnSO4, ZS) electrolyte solutions. Combined experimental characterizations with theoretical calculations, the unique passivation layers with vertical arrayed micro-nano structure are clearly observed, as well as the hydrated Zn2+ solvation structure is changed by replacing two ligand water molecules with As-, thus regulating the wettability and interfacial electric field intensity of Zn surfaces, facilitating rapid ionic diffusions within electrolytes and electrodes together with the inhibited side reactions and uniform depositions of Zn2+. When tested in Zn||Zn symmetric cell, the electrolyte containing Ass is extraordinarily stably operated for the long time ≈3700h at both 1mAcm-2 and 1mAhcm-2. In Zn||MnO2 full coin cells, the energy density can still maintain as high as ≈184Whkg-1 at the power density high up to 2kWkg-1, as well as the capacity retention can reach up to 80.5% even after 1000 cycles at 2Ag-1, which are substantially superior to the control cells.

Enhanced hydrogen sequestration through hydrogen foam generation with SDS Co-Injection in subsurface formations

Inherent obstacles of hydrogen injection encompass preferential channeling through larger pathways, hampering microscopic sweep efficiency within porous media. This work pioneers hydrogen foam generation via co-injection with aqueous sodium dodecyl sulfate (SDS) to enhance subsurface hydrogen trapping capacity. SDS addition substantially reduces hydrogen-water interfacial tension and enhances viscoelasticity. In contrast to robust hydrogen foam stability, CO2 foams display compromised integrity, stemming from surfactant aggregation and ensuing infiltration channels that permit aqueous phase CO2 dissolution. Hydrogen foams conversely sustain uniform surfactant films, forestalling hydrogen ingress into water. Synergetic microfluidic and pore-scale simulations visualise mechanisms underlying intensified hydrogen capture and mobility reduction attributed to deformation and flow resistance when traversing constricted pores. Introducing the amphiphilic SDS surfactant considerably promotes hydrogen adsorption through its hydrophobic tail. Core flooding experiments quantify over 2 times hydrogen storage ratio amplification with SDS relative to sole hydrogen injection. The framework contributes pragmatic strategies to harness high-efficiency hydrogen foam for scalable clean energy storage.

Structure and dynamics of aqueous VOSO4 solutions in conventional flow through cell design: a molecular dynamics simulation study.

A theoretical model has been proposed to study the structure and dynamics of aqueous vanadyl sulfate (VOSO4) solution used in the conventional flow (CF) through cell design operating under varying thermodynamic conditions. Classical molecular dynamics simulations have been carried out for aqueous solutions of vanadyl sulfate (VOSO4) and sulfuric acid (H2SO4) at two different concentrations and temperatures considering the temperature dependent degree of dissociation of sulfuric acid. The MD trajectories are used to study the equilibrium structural, dynamical properties such as viscosity, diffusivity and surface tension of the aqueous solution of vanadyl sulfate (VOSO4). According to the new model, the cation-cation and cation-anion interaction should be low in order to have a good current density in the conventional flow through cell design and further explains the importance of considering mass transport when designing high energy density redox flow batteries. The model is further validated by calculating the viscosity of each system, individual diffusion coefficient of each ion and by comparing them with the experimental data wherever they are available.

PH and thiosulfate dependent microbial sulfur oxidation strategies across diverse environments.

Sulfur oxidizing bacteria (SOB) play a key role in sulfur cycling in mine tailings impoundment (TI) waters, where sulfur concentrations are typically high. However, our understanding of SOB sulfur cycling via potential S oxidation pathways (sox, rdsr, and S4I) in these globally ubiquitous contexts, remains limited. Here, we identified TI water column SOB community composition, metagenomics derived metabolic repertoires, physicochemistry, and aqueous sulfur concentration and speciation in four Canadian base metal mine, circumneutral-alkaline TIs over four years (2016 - 2019). Identification and examination of genomes from nine SOB genera occurring in these TI waters revealed two pH partitioned, metabolically distinct groups, which differentially influenced acid generation and sulfur speciation. Complete sox (csox) dominant SOB (e.g., Halothiobacillus spp., Thiomonas spp.) drove acidity generation and S2O3 2- consumption via the csox pathway at lower pH (pH ~5 to ~6.5). At circumneutral pH conditions (pH ~6.5 to ~8.5), the presence of non-csox dominant SOB (hosting the incomplete sox, rdsr, and/or other S oxidation reactions; e.g. Thiobacillus spp., Sulfuriferula spp.) were associated with higher [S2O3 2-] and limited acidity generation. The S4I pathway part 1 (tsdA; S2O3 2- to S4O6 2-), was not constrained by pH, while S4I pathway part 2 (S4O6 2- disproportionation via tetH) was limited to Thiobacillus spp. and thus circumneutral pH values. Comparative analysis of low, natural (e.g., hydrothermal vents and sulfur hot springs) and high (e.g., Zn, Cu, Pb/Zn, and Ni tailings) sulfur systems literature data with these TI results, reveals a distinct TI SOB mining microbiome, characterized by elevated abundances of csox dominant SOB, likely sustained by continuous replenishment of sulfur species through tailings or mining impacted water additions. Our results indicate that under the primarily oxic conditions in these systems, S2O3 2- availability plays a key role in determining the dominant sulfur oxidation pathways and associated geochemical and physicochemical outcomes, highlighting the potential for biological management of mining impacted waters via pH and [S2O3 2-] manipulation.

Green Synthesis of Copper Nanoparticles Using Leaf Extract of Phyllanthus niruri Lin. and Study of Its Antimicrobial Activity

Abstract: Nanoscience and Nanotechnology are the study and application of extremely small things and can be used across all the other science fields such as chemistry, biology, physics and engineering. Green synthesis of nanoparticles using plant extract is a promising and ecofriendly approach, often yielding particles with unique properties. The present study deals with biosynthesis, characterization and antimicrobial activity. Of copper sulphate nanoparticles using the leaf extract of Phyllanthus niruri. In this report, aqueous phase green synthesis of specifically copper sulphate nanoparticles using leaf extract (both fresh and dry leaf) aqueous leaf extract of leaf was used for the synthesis of nanoparticles. The synthesised nanoparticles of copper sulphate were confirmed by color change when 25ml of 1% aqueous copper sulphate solution was added to 5ml og plant extract. The synthesised nanoparticles were charecterised by UV-Visible spectroscopy, SEM (Scanning Electron Microscopy), and XRD (X-Ray Diffraction). The UV-VIS spectroscopy showed the absorption peak at 378nm for fresh leaf and 376nm for dry leaf. SEM was used to study the morphological features that was predominately spherical and aggregated into large structure with not welldefined morphology and the size347nm,358nm,400nm,457nm, for fresh leaf 1.13µm,1.14µm,771nm,935nm for dry leaf. XRD using this the particle size and nature of nanoparticle was found the average diameter of copper nanoparticles is 12.8nm for dry leaf and 6.10nm for fresh leaf. antimicrobial activity was done using different bacterial and fungal species, in antibacterial activity St. aureus show maximum inhibition that is 75% in fresh leaf and 63%in dry leaf while compare to others, S. typhi showed 0% inhibition it was not resistant towards P.niruri. In antifungal activity F.oxysporum has shown maximum inhibition that is 77% for both fresh and dry leaf, penicillium atramentosum showed 0% inhibition it was not resistant towards P.niruri

The investigation of ion association characteristics in lanthanum sulfate solution by the density functional theory and molecular dynamics simulations

The ion association behavior in aqueous lanthanum sulfate solutions was investigated using density functional theory (DFT). The structures and properties of [La(SO4)m·(H2O)n](3–2m) clusters, where m = 1 to 3 and n = 1 to 9, were examined at the PBE0/6-311+G(d, p) level. The results show that Lanthanum sulfate hydrated clusters exist in the aqueous solution's microscopic state of contact ion pairs (CIP). [La(SO4)(H2O)n]+ and [La(SO4)2·(H2O)n]-, and [La(SO4)3·(H2O)n]3- clusters approximately reach the saturation of the first water shell at n = 7 and 6 and 3. [La(SO4)2·(H2O)6]- and [La(SO4)3·(H2O)3]3- clusters have lower binding energy than [LaSO4·(H2O)n]+. This indicates that lanthanum sulfate tends to aggregate in an aqueous solution. Compared to the gas-phase cluster structures, the distance of R(La–O)H2O expands in the PCM solvent model, while R(La–O)SO4 contracts. The hydration energy of LaSO4·(H2O)7, La(SO4)2·(H2O)6, and La(SO4)3·(H2O)3 were −76.5, −54.1 and −332.0 kcal/mol, respectively. The molecular dynamics simulation results show that La is more inclined to coordinate with sulfate's oxygen than water's oxygen, and the coordination number of water around La3+ is 6.075. These results are consistent with the calculated results by DFT.

Using Magnetic Micelles Combined with Carbon Fiber Ionization Mass Spectrometry for the Screening of Trace Triazine Herbicides from Aqueous Samples.

Triazine herbicides are commonly used in agriculture to eliminate weeds. However, they can persist in the environment. In this study, we explored a new method for detecting triazine herbicides in aqueous samples. We selected two triazine herbicides, namely, prometryn and ametryn, as model herbicides. To generate magnetic probes, we mixed aqueous Gd3+ with aqueous sodium dodecyl sulfate (SDS), which created magnetic probes made of Gd3+-SDS micelles. These probes showed a trapping capacity for the model herbicides. Results indicated that the trapping capacities of our magnetic probes for ametryn and prometryn were approximately 466 and 468 nmol mg-1, respectively. The dissociation constants of our probes toward ametryn and prometryn were 2.92 × 10-5 and 1.27 × 10-5, respectively. This is the first report that the developed magnetic probes can be used to trap triazine herbicides. For detection, we used carbon fiber ionization mass spectrometry (CFI-MS), which can be used to directly detect semi-volatiles from the samples in the condensed phase. Because of the semi-volatility of triazine herbicides, the herbicides trapped by the magnetic probes can be directly analyzed by CFI-MS without any elution steps. In addition, we also demonstrated the feasibility of using our approach for detecting triazine herbicides in lake water and drinking water.

Photo-Chemical Sucralose Degradation in an Aqueous Medium Using a Photo-Fenton System Equipped with Stainless Steel Mesh Cathodes Modified By Nanostructured TiO2- and C|TiO2-Based Films for Continuous Electro-Generation of H2O2

Artificial non-caloric sweeteners are non-bioassimilable substances that pass through the human body without biochemical changes. Sucralose, for instance, is 600 times sweeter than natural sucrose, so it is widely used in beverages and processed food products without regulation in many countries. Its environmental persistence of 337 days in sludge allows inferring that these substances can adversely affect the environment in the short or long term, thus classifying sucralose as an emergent pollutant. In this work, stainless steel (SS) mesh working electrodes were modified by TiO2- or C|TiO2-based nanoparticulate films (where C is carbon Vulcan). Both types of electrodes were employed as cathodes for the electro-generation of hydrogen peroxide (H2O2), which was the chemical precursor for photochemical producing •OH radicals able for sucralose degradation in a photo-Fenton system equipped with a 254 nm light source. Preparation of TiO2- and C|TiO2-based cathodes was performed by electrophoretic deposition method (EPD, 2 V/cm for 40 s) on AISI 304 SS mesh, followed by sintering at 450°C for 1h in the air. The EPD process was performed using aqueous colloidal suspensions containing wt./wt. ratios of C/TiO2 = 1/100 and 1/10, or TiO2 without C for comparison purposes. H2O2 electro-generation was carried out via Reaction 1 utilizing a two-electrode cell (3V-cell polarization) containing sucralose dissolved in a pH 2 aqueous sulfates buffer solution perpetually bubbled by air (volumetric flow rate of 17 mL/s) containing gaseous O2. In all the cases, a Ti grade 2.0 rod anode was immersed in the electrolyte medium with one of the following cathodes: SS* (polished, degreased, and heated at 450°C for 1h in the air as control electrode), SS||TiO2 and SS||C|TiO2 (wt./wt. ratios of C/TiO2 = 1/100 or 1/10). Furthermore, the cell was illuminated by a 254 nm lamp in order to continuous promotion of the photo-chemical Reaction 2.O2 + 2H+ + 2e- → H2O2 ...............(1)H2O2 254mn→ 2°OH...................... (2)Sucralose degradation efficiencies were registered based on the cathodes employed for continuous H2O2 electro-generation. Furthermore, the relative use time was also registered for each cathode. A comparison of these results reveals that when employed SS*, SS||TiO2, and SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/100) cathodes the sucralose degradation achieved efficiencies over 90% (i.e. 99.1, 96.8, and 91.3%, respectively). In contrast, SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/10) cathodes showed a sucralose degradation efficiency of only 88.6%. Furthermore, the SS||TiO2 and SS||C|TiO2 cathodes showed durability 3 times higher than for the SS* cathodes, and 1.8 times higher than for SS||C|TiO2 (wt./wt. ratio of C/TiO2=1/10). These observations indicated that both, SS||TiO2 and SS||C|TiO2 cathodes are strong candidates for assembling more efficient photo-Fenton systems for the degradation of sucralose and other artificial sweeteners.

Effect of Antisolvent Additives in Aqueous Zinc Sulfate Electrolytes for Zinc Metal Anodes: The Case of Acetonitrile.

Aqueous zinc-ion batteries (ZIBs) employing zinc metal anodes are gaining traction as batteries for moderate to long duration energy storage at scale. However, corrosion of the zinc metal anode through reaction with water limits battery efficiency. Much research in the past few years has focused on additives that decrease hydrogen evolution, but the precise mechanisms by which this takes place are often understudied and remain unclear. In this work, we study the role of an acetonitrile antisolvent additive in improving the performance of aqueous ZnSO4 electrolytes using experimental and computational techniques. We demonstrate that acetonitrile actively modifies the interfacial chemistry during Zn metal plating, which results in improved performance of acetonitrile-containing electrolytes. Collectively, this work demonstrates the effectiveness of solvent additive systems in battery performance and durability and provides a new framework for future efforts to optimize ion transport and performance in ZIBs.

Effect of Linear Energy Transfer on Cystamine's Radioprotective Activity: A Study Using the Fricke Dosimeter with 6-500 MeV per Nucleon Carbon Ions-Implication for Carbon Ion Hadrontherapy.

(1) Background: Radioprotective agents have garnered considerable interest due to their prospective applications in radiotherapy, public health medicine, and situations of large-scale accidental radiation exposure or impending radiological emergencies. Cystamine, an organic diamino-disulfide compound, is recognized for its radiation-protective and antioxidant properties. This study aims to utilize the aqueous ferrous sulfate (Fricke) dosimeter to measure the free-radical scavenging capabilities of cystamine during irradiation by fast carbon ions. This analysis spans an energy range from 6 to 500 MeV per nucleon, which correlates with "linear energy transfer" (LET) values ranging from approximately 248 keV/μm down to 9.3 keV/μm. (2) Methods: Monte Carlo track chemistry calculations were used to simulate the radiation-induced chemistry of aerated Fricke-cystamine solutions across a broad spectrum of cystamine concentrations, ranging from 10-6 to 1 M. (3) Results: In irradiated Fricke solutions containing cystamine, cystamine is observed to hinder the oxidation of Fe2+ ions, an effect triggered by oxidizing agents from the radiolysis of acidic water, resulting in reduced Fe3+ ion production. Our simulations, conducted both with and without accounting for the multiple ionization of water, confirm cystamine's ability to capture free radicals, highlighting its strong antioxidant properties. Aligning with prior research, our simulations also indicate that the protective and antioxidant efficiency of cystamine diminishes with increasing LET of the radiation. This result can be attributed to the changes in the geometry of the track structures when transitioning from lower to higher LETs. (4) Conclusions: If we can apply these fundamental research findings to biological systems at a physiological pH, the use of cystamine alongside carbon-ion hadrontherapy could present a promising approach to further improve the therapeutic ratio in cancer treatments.