Ultrapure Water Research Articles

Abstract 2096: Role Of Divalent Cations In The Enzymatic Activation Of Coagulation Factor XII By Lipopolysaccharides

Background: Lipopolysaccharide (LPS) is the primary pathogenic factor in Gram-negative sepsis. LPS is a polyanionic molecule that may act as a site of initiation of coagulation by activating factor (F)XII. While the physicochemical properties of LPS are known to be sensitive to interactions with divalent cations, it is unknown whether divalent cations modulate the activation of FXII by LPS. Aims: To determine whether divalent cations regulate the kinetics of FXII activation by select LPS chemotypes from E. coli . Methods: Aggregates of E. Coli LPS chemotypes O26:B6 and Rd2 were prepared in ultrapure water in the presence or absence of calcium (Ca 2+ ). The biophysical characterization of LPS chemotypes were determined by dynamic light scattering (DLS) and measurement of zeta potential (ZP). Chromogenic substrate assays were used to study the effects of LPS on FXII activation. Results: The LPS O26:B6 and Rd2 in the absence of Ca 2+ produced aggregates in form of micelles with hydrodynamic diameters of 190±10 and 200±7 nm and ZP of -25±0.8 and -60±2 mV, respectively. The presence of Ca 2+ produced aggregates in the form of vesicles with hydrodynamic diameters of 400±15 and 1300±60 nm and ZP of –11±2 and –3±0.5 mV, respectively. FXII was incubated in HEPES buffer with the distinct LPS morphologies in varying salt concentrations. We found maximal autoactivation of FXII by O26:B6 and Rd2 chemotypes at lower NaCl concentrations. The presence of Ca 2+ , however, selectively reduced the ability of O26:B6 to activate FXII. Strikingly, the neutralization of the surface net charge of the LPS chemotype Rd2 by Ca 2+ ions abrogated the amidolytic activity of Rd2. Conclusions: The presence of calcium ions induces changes in the physicochemical properties of LPS that result in distinct effects on FXII activation in vitro . We are currently studying whether this phenomena is conserved for other divalent cations including Zn, Mg, Cu, and Mn.

Cubic structured core/shell NiFe2O4@ZnFe2O4 nanocomposite: Structural, morphological and magnetic properties

Double ferrite nanocomposites with NiF2O4 as the core and ZnFe2O4 as the shell, were synthesised through combination of co-precipitation and hydrothermal methods. This two-step process resulted in formation of a cubic structured core of around 100 nm and a shell of zinc ferrite nanoparticles which are below 10 nm in size. The core/shell structures were characterised using various techniques such as XRD, Raman, TEM/EDS and VSM. In addition, Ni leaching out of these structures was tested in the ultra-pure water and saline solution. These analyses demonstrated that the shell of zinc ferrites effectively prevents Ni leaching from the core keeping the concentration of nickel well below the level usually found in drinking water. These core/shell nanocomposites exhibit a ferrimagnetic behaviour.

PocketWATCH: design and operation of a multi-use test bed for water Cherenkov detector components in pure and gadolinium loaded water

The PocketWATCH facility is a unique multi-purpose test bed designed to replicate the conditions of large water Cherenkov detectors. Housed at the University of Sheffield, the facility consists of a light-tight 2000 L ultrapure water tank with purification and temperature control systems. Water temperature, resistivity, and UV attenuation in the tank are monitored and shown to be stable over time. The system is also shown to be compatible with a solution of 0.2% gadolinium sulfate, allowing further utility in testing equipment bound for the next generation neutrino and nucleon decay water Cherenkov particle detectors. The relevant water quality parameters are shown to be stable whilst running in Gd-mode, thereby providing a suitable test bed for hardware development in a realistic, ex situ environment.

Influence of suspended particles and dissolved organic matters on virus enrichment in reclaimed water by two-step tangential flow ultrafiltration: Phenomena and mechanisms

Enteric virus concentration in large-volume water samples is crucial for detection and essential for assessing water safety. Certain dissolution and suspension components can affect the enrichment process. In this study, tangential flow ultrafiltration (TFUF) was used as an enrichment method for recovering enteric virus in water samples. Interestingly, the bacteriophage MS2 recovery in reclaimed water and the reclaimed water without particles were higher than that in ultrapure water. The simulated reclaimed water experiments showed that humic acid (HA) (92.16% ± 4.32%) and tryptophan (Try) (81.50 ± 7.71%) enhanced MS2 recovery, while the presence of kaolin (Kaolin) inhibited MS2 recovery with an efficiency of 63.13% ± 11.17%. Furthermore, Atomic force microscopy (AFM) revealed that the MS2-HA cluster and the MS2-Try cluster had larger roughness values on the membrane surface, making it difficult to be eluted, whereas MS2-Kaolin cluster had compact surfaces making it difficult to be eluted. Additionally, the MS2-HA cluster is bound to the membrane by single hydrogen bond with SO, whereas both the MS2-Try cluster and the MS2-Kaolin cluster are bound to the membrane by two hydrogen bonds, making eluting MS2 challenging. These findings have potential implications for validating standardized methods for virus enrichment in water samples.

In situ green immobilization of palladium nanoparticles onto polydopamine-modified eggshell membrane for catalytic reduction of nitrophenols

4-Nitrophenol (4-NP) poses significant threats to both ecosystems and human health, making it essential and highly beneficial to take effective measures to mitigate its impact. Herein, eggshell membrane (ESM) with mussel-inspired polydopamine coatings (ESM-PDA) was constructed and utilized as a template for the immobilization of Pd NPs, resulting in ESM-PDA-Pd formation. The catalyst ESM-PDA-Pd exhibits exceptional performance in reducing 4-NP, and the TOF (turnover frequency) for ESM-PDA-Pd was determined to be 3.3 × 10−5 mmol·mg−1·min−1. Moreover, ESM-PDA-Pd demonstrates excellent catalytic activity in reducing other nitrophenols, including 2-nitrophenol (0.2196 min−1) and 2,4,6-nitrophenol (0.1177 min−1). Notably, the catalyst demonstrated brilliant recyclability, removing 92.4 % of 4-NP within 20 min after undergoing five consecutive runs. This underscores its potential for sustained and effective use in multiple cycles of nitrophenol reduction reactions. Furthermore, the measured Kapp in various water samples is as follows: ultrapure water (0.135 min−1) > tap water (0.109 min−1) > river water (0.083 min−1), indicating its significant potential for industrial applications.

A Precision Measurement System Design for Electrical Conductivity in the Low-Concentration TOC Analysis of the Ultra-pure Water

The concentration of total organic carbon (TOC) in water is an important key indicator of the quality of Ultra-pure water, which is useful in the semiconductor and pharmaceutical industries, among others. Therefore, as a technology to measure TOC, a technology that measures the amount of carbon dioxide (CO<sub>2</sub>) by electrical conductivity is being developed. This method uses ultraviolet light and an oxidizing agent to oxidize organic compounds to produce CO<sub>2</sub>, and measures the concentration of CO<sub>2</sub> by measuring the electrical conductivity based on the permeable membrane of the gas, and then converts it to the concentration of TOC in the organic compound. In this study, we presented the design conditions of the alternating current control circuit applied between the two electrodes of the electrical conductivity cell, the microcurrent signal detection, voltage conversion circuit, and the amplification and noise reduction circuit for measuring the low concentration of TOC required for ultrapure water. Based on the optimal design conditions, we have fabricated a PCB for ultra-precise electrical conductivity measurement for low concentration TOC analysis using membrane conductivity, and have compared the results with a commercial product.

Analysis of Trace Impurities in Lithium Carbonate.

Lithium carbonate (Li2CO3) is a critical raw material in cathode material production, a core of Li-ion battery manufacturing. The quality of this material significantly influences its market value, with impurities potentially affecting Li-ion battery performance and longevity. While the importance of impurity analysis is acknowledged by suppliers and manufacturers of battery materials, reports on elemental analysis of trace impurities in Li2CO3 salt are scarce. This study aims to establish and validate an analytical methodology for detecting and quantifying trace impurities in Li2CO3 salt. Various analytical techniques, including X-ray diffraction (XRD), scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX), X-ray photoelectron spectroscopy (XPS), and inductively coupled plasma optical emission spectroscopy (ICP-OES), were employed to analyze synthetic and processed lithium salt. X-ray diffraction patterns of Li2CO3 were collected via step-scanning mode in the 5-80° 2θ range. SEM-EDX was utilized for particle morphology and quantitative impurity analysis, with samples localized on copper tape. XPS equipped with a hemispherical electron analyzer was employed to analyze the surface composition of the salt. For ICP-OES analysis, a known amount of lithium salt was subjected to acid digestion and dilution with ultrapure water. Multielemental standard solutions were prepared, including elements such as Al, Cd, Cu, Fe, Mn, Ni, Pb, Si, Zn, Ca, K, Mg, Na, and S. Results confirmed the presence of the zabuyelite phase in XRD analysis, corresponding to the natural form of lithium carbonate. SEM-EDX mapping revealed impurities of Si and Al, with low relative quantification values of 0.12% and 0.14%, respectively. XPS identified eight potential impurity elements, including S, Cr, Fe, Cl, F, Zn, Mg, and Na, alongside Li, O, and C. Regarding ICP-OES analysis, performance parameters such as linearity, limit of detection (LOD), and quantification (LOQ), variance, and recovery were evaluated for analytical validation. ICP-OES results demonstrated high linearity (>0.99), with LOD and LOQ values ranging from 0.001 to 0.800 ppm and 0.003 to 1.1 ppm, respectively, for different elements. The recovery rate exceeded 90%. In conclusion, the precision of the new ICP-OES methodology renders it suitable for identifying and characterizing Li2CO3 impurities. It can effectively complement solid-state techniques such as XRD, SEM-EDX, and XPS.

Experimental investigation on the heat transfer performance of pulsating heat pipe with self-rewetting Fe3O4-nanofluid

This paper conducted an experimental study on the heat transfer performance of pulsating heat pipe (PHP) under three different working fluids: ultrapure water, n-butanol self-rewetting fluid (SRWF), and self-rewetting Fe3O4-nanofluid (SRNF). The effects of filling ratio (FR), heating power, and magnetic field are studied. The results mainly show that the PHP with SRNF under a magnetic field, the start-up time increases, the evaporation section operating temperature increases, and the thermal performance decreases as the filling ratio increases. Increasing the FR, applying SRWF and SRNF can effectively increase the dry-out limit of PHP. At FR = 50 %, the overall thermal performance of PHP is best. In 10–130W, the thermal resistance of the SRWF and the SRNF with/without magnetic field is reduced by 14.5 %–27.8 %, 27.6 %–47.9 %, and 4.2 %–24.8 %, respectively, compared with that of ultrapure water. Similarly, compared without a magnetic field, the thermal resistance of SRNF with a magnetic field is reduced by 14.0 %–35.1 %. At FR = 50 %, the heat transfer performance of SRNF-PHP is best with a magnetic field. When the input power is 130W, the effective heat transfer coefficient keff is 5967.6 W/m∙ K, approximately 13.92 times greater than copper.

Aluminium Determination in Foodstuffs by ICP-MS: Influence of Microwave Digestion Parameters on the Recovery

Aluminium (Al) is the third most common element in the Earth’s crust and occurs naturally in drinking water and agricultural products, and humans are consequently exposed to the element from dietary sources. A tolerable weekly intake of 1 mg/kg has been established by the European Food Safety Authority (EFSA); however, no maximum levels for aluminium in foodstuffs have so far been established in the European Union (EU) legislation. Official food control requires validated methods for the determination of aluminium. Acid digestion assisted by microwaves is the main sample preparation technique used for the determination of aluminium, usually in combination with atomic spectrometry for quantification. In the present study, different parameters in the digestion step were investigated including test portion, digestion temperature, the reagent used and duration of the digestion to assess the aluminium extraction. The presented work is following up on an observation from a proficiency test (PT) on trace elements (including aluminium) in cocoa powder organised in 2020 by the European Union Reference Laboratory for metals and nitrogenous compounds in feed and food (EURL-MN), where the participant results for aluminium showed an unexpectedly large variation. In addition to the PT material, different certified reference materials were included in the present study, and the results highlighted that the temperature and reagent used are the most critical parameters to obtain a satisfactory sample digestion prior to aluminium determination. Based on the obtained results, it is recommended to digest food samples with a mix of ultrapure water and nitric acid for 25 min at a temperature of at least 240 °C with a mix of HNO3 and H2O to achieve satisfactory microwave-assisted digestion.

A simple methodology for in situ study of microplastics’ aggregation

AbstractDue to the critical impacts of microplastic (MP) aggregation on their fate, mobility, and bioavailability, this study developed a simple approach to examine their aggregation under varying water chemistry and MPs’ surface aging conditions. An accelerated photodegradation experiment was conducted for 6 weeks. The water chemistry conditions varied by altering pH, using natural organic matter (NOM), and conducting experiments in ultrapure water and synthetic stormwater. The surface chemistry analysis of photodegraded MPs revealed the formation of carbonyl and vinyl functional groups. Zeta potential measurements revealed a more negative surface charge for photodegraded MPs compared to new MPs. The aggregation kinetics of MPs were studied by comparing the number of MP clusters formed over time after intense dispersion in water. The results showed that the presence of NOMs reduces the aggregation tendency of new low‐density polyethylene MPs due to enhanced steric hindrance and electrostatic repulsion. However, variations of pH and utilizing synthetic stormwater versus ultrapure water did not alter the aggregation kinetics of new MPs. The aggregation behavior of photodegraded MPs was significantly different from new MPs. A greater tendency for aggregation of photodegraded MPs was found in the stormwater compared to the ultrapure water. This study contributes to a better understanding of the transport and fate of MPs within the aqueous environment and their subsequent environmental risks.

A green approach for metoclopramide quantification in pharmaceutical products: new HPLC and spectrophotometric methods

Green spectrophotometric and HPLC methods have been developed for the quantification of metoclopramide. In the spectrophotometric method, it was determined by direct absorbance measurement at 273 nm wavelength using ultrapure water as solvent. The Extend C18 column was used for the HPLC method. The mobile phase system consisted of a combination of ethanol and formic acid solution (pH 2.0; 30:70 v/v). Isocratic elution was applied and the flow rate was set at 1.0 mL min−1. Metoclopramide was detected at 273 nm. The methods performed were economical, rapid, environmentally friendly, and simple, providing metoclopramide analysis within 5 min. The methods have been successfully applied in pharmaceutical products without matrix interference. The results of the application of the developed methods to pharmaceutical products were statistically compared and no significant difference was observed between the methods. In addition, the greenness assessment of the developed methods was performed using AGREE software. Our developed methods, based on the use of solvents such as ethanol and water, are proposed as a more environmentally and analyst-friendly option for the quantification of metoclopramide in pharmaceutical products than other methods currently in use.

Experimental study to characterize water contaminated by lunar dust

The establishment of a permanent lunar base is the goal of several space missions, such as NASA’s Artemis program. The feasibility of a lunar base is highly dependent on the supply of clean water, which can be recycled within the life support system or extracted in-situ on the Moon. Contamination of the water by lunar dust is an unavoidable problem due to the fact that lunar dust covers the entire surface and has adhesive properties as well as a very fine particle size. It is therefore important to study and characterise water contaminated by lunar dust in order to develop a safe water supply system. We combined existing studies on the dissolution behaviour of lunar regolith in aqueous solutions and performed dissolution experiments ourselves. We conducted dissolution experiments using the Lunar Highland Dust simulant from Exolith Lab (Orlando, United States), which resembles the Apollo 16 regolith and thus the terrain of the suspected Artemis landing sites. Our dissolution experiments investigate the effects of the dust to solution ratio, the aqueous solution used (ultrapure water and 5.5 buffer), the short exposure time (2 min up to 72 h), the dissolved oxygen in the solutions and the particle size of the simulant. As a result, this study provides a characterisation of lunar dust contaminated water and compares the results with the World Health Organization (WHO) and NASA requirements for drinking water. For all test batches, the lunar dust contaminated water exceeds the requirements for pH, turbidity and Al concentration.

Hydrophobic carbon quantum dots with red fluorescence: An optical dual-mode and smartphone imaging sensor for identifying Chinese Baijiu quality

Chinese Baijiu (Liquor) is a popular alcoholic beverage, and the ethanol content in Baijiu is closely related to its quality; therefore, it is of great significance to explore a facile, sensitive, and rapid method to detect ethanol content in Baijiu. Hydrophobic carbon quantum dots (H-CQDs) with bright red fluorescence (24.14 %) were fabricated by hydrothermal method using o-phenylenediamine, p-aminobenzoic acid, manganese chloride, and hydrochloric acid as reaction precursors. After the introduction of ultrapure water into the ethanol solution dissolved with H-CQDs, the aggregated H-CQDs resulted in significant changes in fluorescence intensity and absorbance. On this basis, a sensor for detecting ethanol by optical dual-mode and smartphone imaging was constructed. More importantly, the sensor can be used for detecting ethanol content in Chinese Baijiu with satisfactory results. This sensing platform has great potential for quality identification in Chinese Baijiu, broadening the application scope of CQDs in food safety detection.

Degradation and mineralization of anti-cancer drugs Capecitabine, Bicalutamide and Irinotecan by UV-irradiation and ozone

The degradation of three anti-cancer drugs (ADs), Capecitabine (CAP), Bicalutamide (BIC) and Irinotecan (IRI), in ultrapure water by ozonation and UV-irradiation was tested in a bench-scale reactor and AD concentrations were measured through ultra-high-performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS). A low-pressure mercury UV (LP-UV) lamp was used and degradation by UV (λ = 254 nm) followed pseudo-first order kinetics. Incident radiation in the reactor was measured via chemical actinometry using uridine. The quantum yields (φ) for the degradation of CAP, BIC and IRI were 0.012, 0.0020 and 0.0045 mol Einstein−1, respectively. Ozone experiments with CAP and IRI were conducted by adding ozone stock solution to the reactor either with or without addition of tert-butanol (t-BuOH) as radical quencher. Using this experimental arrangement, no degradation of BIC was observed, so a semi-batch setup was employed for the ozone degradation experiments of BIC. Without t-BuOH, apparent second order reaction rate constants for the reaction of the ADs with molecular ozone were determined to be 3.5 ± 0.8 ∙ 103 L mol−1 s−1 (CAP), 7.9 ± 2.1 ∙ 10−1 L mol−1 s−1 (BIC) and 1.0 ± 0.3 ∙ 103 L mol−1 s−1 (IRI). When OH-radicals (∙OH) were quenched, rate constants were virtually the same for CAP and IRI. For BIC, a significantly lower constant of 1.0 ± 0.5 ∙ 10−1 L mol−1 s−1 was determined. Of the tested substances, BIC was the most recalcitrant, with the slowest degradation during both ozonation and UV-irradiation. The extent of mineralization was also determined for both processes. UV irradiation was able to fully degrade up to 80% of DOC, ozonation up to 30%. Toxicity tests with Daphnia magna (D. magna) did not find toxicity for fully degraded solutions of the three ADs at environmentally relevant concentrations.

Phase behavior of sodium and potassium salts in their aqueous solutions: Experiment and computational thermodynamics

AbstractWith the rapid development of the semiconductor industry, the demand for ultraclean and high‐purity electronic chemicals, especially ultrapure water as a general solvent for cleaning semiconductor chips, has increased dramatically. The distillation process is a good choice for large‐scale production of ultrapure water that can be used to clean semiconductor chips, but there is a lack of basic thermodynamic theory for removing ionic impurities. In this work, the temperature and vapor–liquid phase composition of sodium and potassium salts aqueous solutions at vapor–liquid equilibrium (VLE) were investigated by experiments. The microstructure of each inorganic salt aqueous solution was explored by molecular dynamics simulation and quantum chemical calculation, and the interaction between each ion and water molecule was analyzed. A volatilization mechanism of inorganic salts was proposed, and it was found that the volatilization of inorganic salts in an aqueous solution was affected by the strength of interaction between the dissociated anions and cations and water molecules. Finally, the conductor‐like screening model segment activity coefficient (COSMO‐SAC) model predicted the VLE values of inorganic salt aqueous solutions. The prediction at low concentrations (xs < 0.06) was in good agreement with the experimental data.

Simultaneous determination of eight organic amines in desulfurization solution by ion chromatography

The applications of organic-amine desulfurization have steadily increased owing to its high efficiency, low cost, and low energy consumption. Different proportions of organic amines exert different effects on sulfur dioxide removal. Therefore, the accurate determination of different organic amines in the desulfurization solution is of great importance. The ion-chromatographic method for the detection of organic amines does not require a derivatization step, has simple pretreatment procedures, and allows for the simultaneous determination of many types of organic amines. In this study, a method based on ion chromatography was developed for the simultaneous determination of ethanolamine (MEA), diethylethanolamine (DEEA), n-methyldiethanolamine (MDEA), 2-amino-2-methyl-1-propanol (AMP), hydroxyethylethylenediamine (AEEA), piperazine (PZ), n-hydroxyethylpiperazine (HEPZ), and diethylenetriamine (DETA). The separation efficiency of the eight organic amines in different types of columns, leaching solutions, and column temperatures were compared. The determination was performed using an IonPac CS17 column with column temperature of 35 ℃ and gradient leaching with methyl sulfonic acid (MSA) solution via the inhibition conductance method. Samples of the desulfurization solution were analyzed using ultrapure water filtered through a 0.22 μm nylon microporous filter membrane and an OnGuard Ⅱ RP column; thus, the pretreatment steps are simple. The eight organic amines showed a good linear relationship within a certain concentration range, and the coefficient of determinations (R2) were greater than 0.998. The limits of detection (LODs) and quantification (LOQs) were determined from the mass concentrations of the organic amines corresponding to signal-to-noise ratios (S/N) of 3 and 10, respectively. LODs of 0.02-0.08 mg/L and LOQs of 0.07-0.27 mg/L were determined from a 1.0 μL sample injection. The actual recoveries ranged from 93.0% to 111%, and the relative standard deviations (RSDs, n=5) ranged from 0.31% to 1.2%. The results indicated that the proposed method has good accuracy and precision; thus, it is suitable for the determination of various organic amines in desulfurization solution.

Non-clinical Safety Evaluation of Camelina Oil: Acute and 12-Week Oral Toxicities.

This study assessed the acute and sub-chronic toxicity of Camelina oil, a well-known oil rich in polyunsaturated fatty acids that enhance cellular immunity and human health, in Wistar rats. Wistar rats, 5 per sex per group, were randomly assigned to three groups for acute (14 days) toxicity studies and five groups for sub-chronic (90 days) toxicity studies. In the acute study, Camelina sativa oil was administered orally at a single dose of 5000 mg/kg of body weight (BW). The positive control group received a single dose of 5 000 mg/kg BW Canola oil by gavage. In the sub-chronic study, Groups III-V received 250, 500, and 1 000 mg/kg BW of Camelina oil, while Groups I and II received ultra-pure water and Canola oil at a dose of 500 mg/kg BW, respectively. Throughout the experiment, clinical signs, mortality, and body weight were monitored. At the end of the sub-chronic study, hematological, biochemical, and histopathological investigations were conducted. Administration of Camelina oil and Canola had no significant effect on daily weight gain (P > 0.05) of the test rats. Serum calcium levels decreased while phosphorous levels increased in male rats treated with Camelina oil. Other hematological and biochemical parameters showed no significant differences or dose-response effects between control and seed oil groups in both sexes (P < 0.05). Moreover, in animal necropsy, there were no apparent lesions in the liver, heart, and kidney organs in any of the doses administered. In conclusion, the results suggest that oral administration of Camelina oil is unlikely to be toxic. Therefore, the possibility for the development of future human nutrition should be considered.

The addition of mammalian cell culture medium impacts nanoparticle toxicity in zebrafish

Engineered nanomaterials (ENMs) are ubiquitous in contemporary applications, yet their environmental and human health impacts remain inadequately understood. This study addresses the challenge of identifying potential risks associated with ENM exposure by highlighting the significant variability in existing research methodologies. Without a systematic collection of toxicological data that encompasses standardized materials, relevant platforms, and assays, the task of identifying potential risks linked to ENM exposure becomes an intricate challenge. In vitro assessments often use media rich in ionic species, such as RPMI and fetal bovine serum (FBS). Zebrafish embryos, known to develop normally in low-ionic environments, were exposed to Cerium Oxide, Zinc Oxide, and Graphene Oxides in different media at varying concentrations. Here, we discovered that zebrafish embryos tolerated a mix of 80 % RPMI, 2 % FBS, and 1 % antibiotic cocktail. The results revealed that adverse effects observed in zebrafish with certain nanomaterials in Ultra-Pure (UP) water were mitigated in cell culture medium, emphasizing the importance of revisiting previously considered non-toxic materials in vitro. The zebrafish results underscore the importance of utilizing a multidimensional in vivo platform to gauge the biological activity of nanomaterials accurately.

Sprayed Oil-Water Microdroplets as a Hydrogen Source.

Liquid water provides the largest hydrogen reservoir on the earth's surface. Direct utilization of water as a source of hydrogen atoms and molecules is fundamental to the evolution of the ecosystem and industry. However, liquid water is an unfavorable electron donor for forming these hydrogen species owing to its redox inertness. We report oil-mediated electron extraction from water microdroplets, which is easily achieved by ultrasonically spraying an oil-water emulsion. Based on charge measurement and electron paramagnetic resonance spectroscopy, contact electrification between oil and a water microdroplet is demonstrated to be the origin of electron extraction from water molecules. This contact electrification results in enhanced charge separation and subsequent mutual neutralization, which enables a ∼13-fold increase of charge carriers in comparison with an ultrapure water spray, leading to a ∼16-fold increase of spray-sourced hydrogen that can hydrogenate CO2 to selectively produce CO. These findings emphasize the potential of charge separation enabled by spraying an emulsion of liquid water and a hydrophobic liquid in driving hydrogenation reactions.

Synthesis and transformation of graphene-like structures from bamboo waste for photoelectrochemical devices

This study presents a sustainable and versatile approach to synthesize graphene-like structures from bamboo waste for application in photoelectrochemical (PEC) devices. Due to its high cellulose content, bamboo, a locally available and renewable resource, is a perfect precursor for producing graphene-like materials. The synthesis process involves bamboo waste pyrolysis, followed by treatments with different solvents: ultrapure water (UPW), NaOH, and green tea extract. Characterization techniques confirmed the successful transformation of bamboo waste into carbon-rich, graphene-like materials with varying surface properties. The electrochemical characterization showed that the graphene-like materials could transfer electrons very well with a high current response compared to charcoal as a precursor. PEC evaluations revealed their potential as photoanodes, exhibiting efficient light absorption and charge carrier separation. This research emphasizes the significance of bamboo waste as a valuable precursor for eco-friendly graphene-like materials, offering a sustainable pathway for developing efficient PEC devices and green energy technologies.