Hydroxyl Radical Research Articles

Investigating the antioxidant properties and GC-MS profile of Indian native medicinal flower Pandanus odorifer and assessing its cytotoxic effects on HT-29 cells

This study aimed to investigate the antioxidant potential and bioactive compounds of Pandanus odorifer flower. The phytochemical investigation includes both qualitative and quantitative experiments. In vitro antioxidant studies were conducted using DPPH, ABTS and hydroxyl methods. The bioactive compounds present in the ethanol extract were identified using GC-MS analysis. The MTT assay was carried out on HT-29 colon cancer cells to investigate the cytotoxic ability of the ethanolic extract. The qualitative phytochemical analysis demonstrated the presence of flavonoids, phenolic compounds, tannins, saponins, steroids, carboxylic acids and cardiac glycosides. The determination of flavonoid showed 400 ± 0.110 mg/g and 250±0.090 mg/g of quercetin equivalent in ethanol and water extracts. Similarly, the determination of phenol exhibited 108±0.210 mg/g and 87±0.173 mg/g gallic acid equivalent in ethanol and water extracts. The total antioxidant capacity revealed 1.6 ± 0.093 mg/g and 1.3± 0.056 mg/g equivalent of ascorbic acid in ethanol and water extracts. The DPPH assay showed IC50 values of 35.06 µg/mL in ethanol and 44.82 µg/mL in water extract. Likewise, the ABTS assay revealed an IC50 value of 42.20 µg/mL and 47.45 µg/mL in ethanol and water extract. The hydroxyl radical assay showed IC50 value of 23.95 µg/mL in ethanol and 36.56 µg/mL in water extract. 22 bioactive compounds were identified using GC-MS analysis based on their similarity index. The ethanolic extract showed greater cytotoxic activity with the IC50 value of 28.08 µg/mL on HT-29 colon cancer cells. This study concludes that the Pandanus odorifer flower extracts exhibited significant antioxidant and cytotoxic property.

Electrochemical generation of H*-•OH redox pair for rapid removal of refractory nitro-organic micropollutants

This study developed an innovative reduction-oxidation coupling process for treatment of refractory organic wastewater. We constructed a series of N5-coordinated transition metals (TMs) (TMs = Mn, Fe, Co, Ni, Cu) single-atom sites supported on nitrogen-rich carbon nitride (SA-TM-C3N5) for electrochemical generation of the surface-adsorbed hydrogen atom (H*) and hydroxyl radical (•OH). The SA-Co-C3N5 exhibited the highest activity for production of the H*-•OH redox pair, which effectively degraded refractory nitro-organic micropollutants via the parallel reduction-oxidation pathways. The SA-Co-C3N5-mediated electro-Fenton-like system showed high removal efficiency (99 %) and mineralization capacity (78 %) toward metronidazole (MNZ) with low energy consumption (0.019 kWh (g TOC)–1). The trifunctional properties of the H* have contributed to the reduction of nitro compounds, the 2e– ORR for H2O2 production and the Fenton-like catalysis for •OH generation. This work sheds lights on the development of advanced reduction-oxidation coupling process for green and sustainable water purification.

Regulating Hydroxyl Radicals (•OH) and Hydrated Electron (eaq) for Enhanced Radiolytic Degradation of 4-Nitrophenol by Addition of H2O2

Regulating Hydroxyl Radicals (^•OH) and Hydrated Electron (e_aq) for Enhanced Radiolytic Degradation of 4-Nitrophenol by Addition of H₂O₂

Dual-Activated Photoacoustic Probe for Reliably Detecting Hydroxyl Radical in Ischemic Cardiovascular Disease in Mouse and Human Samples.

Cardiovascular disease (CVD) is a chronic disease characterized by the accumulation of lipids and fibrous tissue within the arterial walls, potentially leading to vascular obstruction and an increased risk of heart disease and stroke. Hydroxyl radicals play a significant role in the formation and progression of CVD as they can instigate lipid peroxidation, resulting in cellular damage and inflammatory responses. However, precisely detecting hydroxyl radicals in CVD lesions presents significant challenges due to their high reactivity and short lifespan. Herein, we present the development and application of a novel activatable optical probe, Cy-OH-LP, designed to detect hydroxyl radicals in lipid-rich environments specifically. Built on the Cy7 molecular skeleton, Cy-OH-LP exhibits near-infrared absorption and fluorescence characteristics, and its specific response to hydroxyl radicals enables a turn-on signal in both photoacoustic and fluorescence spectra. The probe demonstrated excellent selectivity and stability in various tests. Furthermore, Cy-OH-LP was successfully applied in an in vivo model to detect hydroxyl radicals in mouse models, providing a potential tool for diagnosing and monitoring AS. The biosafety of Cy-OH-LP was also verified, showing low cytotoxicity and no significant organ damage in mice. The findings suggest that Cy-OH-LP is a promising tool for the specific detection of hydroxyl radicals in lipid-rich environments, providing new possibilities for research and clinical applications in the field of oxidative stress-related diseases.

Effects of photodynamic therapy using bisdemethoxycurcumin combined with melatonin or acetyl-melatonin on C. Albicans

The current study aims to explore the efficacy of antifungal photodynamic therapy (PDT) on C. albicans biofilms by combining photosensitizers, bisdemethoxycurcumin (BDMC), and melatonin (MLT) or acetyl-melatonin (AcO-MLT). Additionally, the relationship between different types of reactive oxygen species and PDT’s antifungal efficacy was investigated. BDMC, MLT and AcO-MLT were applied, alone and in combination, to 48-hour C. albicans biofilm cultures (n = 6/group). Blue and red LED light (250 mW/cm2 with 37.5 J/cm2 for single or 75 J/cm2 for dual photosensitizer groups) were used to irradiate BDMC groups and MLT/AcO-MLT groups, respectively. For combination groups, blue LEDs and subsequently red LEDs were used. Drop plate assays were performed at 0, 1 and 6 h post-treatment. Colony forming units (CFUs) were then counted after 48 h. Hydroxyl radicals and singlet oxygen were measured using fluorescence spectroscopy and electron spin resonance (ESR) spectroscopy. Additionally, cell cytotoxicity was tested on human oral keratinocytes. Significant CFU reductions were observed with combinations 20 µM BDMC + 20 µM AcO-MLT and 60 µM BDMC + 20 µM MLT at 0 and 1 h post-treatment, respectively. Singlet oxygen production increased with the addition of MLT/AcO-MLT and had moderate-substantial correlations with inhibition at all times. Hydroxyl radical production was not significantly different from the control. Additionally, BDMC exhibited subtle cytotoxicity on human oral keratinocytes. PDT using BDMC + MLT or AcO-MLT, with blue and red LED light, effectively inhibits C. albicans biofilm through singlet oxygen generation. Melatonin acts as a photosensitizer in PDT to inhibit fungal infection.

Square-wave pulsed potential driven electrocatalytic degradation of 4-chlorophenol using Fe-Ni/rGO/PPy@NF three dimensional electrode

To develop an energy-efficient system for the removal of chlorinated organic pollutants, Fe-Ni/reduced graphite oxide/polymerized polypyrrole@nickel foam was constructed as a catalytic cathode for pulsed electrocatalytic degradation, where cathode-catalyzed production of hydrogen radicals (H*) and hydroxyl radical (·OH) generated at the anode led to dechlorination of 4-chlorophenol (4-CP), and dechlorination products were mineralized and degraded under the action of·OH. When energy was continuously supplied to the reaction system in the constant potential mode, the 4-CP concentration near the electrode was insufficient, limiting the reaction rate. Conversely, in the square-wave pulsed potential mode, mass transfer limitations were mitigated, significantly enhancing reaction efficiency and reducing energy consumption. At −1.2 V (vs. Ag/AgCl), the 4-CP removal efficiency reached 93.79 % in the pulsed potential mode, surpassing the constant potential mode's performance of 81.40 %. The synergistic periodic oscillation of the potential, direct electron transfer, and catalytic generation of active free radicals in the pulsed potential mode reduced intermediate concentrations and increased 4-CP mineralization, while the degradation pathway remained unchanged. This research presents a method for the efficient treatment of chlorinated organic pollutants in water using pulsed electrocatalytic degradation.

Oxidative stability of chelated Sn(II)(aq) at neutral pH: The critical role of NO3- ions.

Tin(II) compounds are versatile materials with applications across fields such as catalysis, diagnostic imaging, and therapeutic drugs. However, oxidative stabilization of Sn(II) has remained an unresolved challenge as its reactivity with water and dioxygen results in loss of functionality, limiting technological advancement. Approaches to slow Sn(II) oxidation with chelating ligands or sacrificial electron donors have yielded only moderate improvements. We demonstrate here that the addition of nitrate to pyrophosphate-chelated Sn(II)(aq) suppresses Sn(II) oxidation in water across a broad pH range. Evidence of hydroxyl radical concentration reduction and detection of a radical nitrogen species that only forms in the presence of chelated Sn(II) point to a radical-based reaction mechanism. While this chemistry can be broadly applied, we present that this approach maintains Sn(II)'s antibacterial and anti-inflammatory efficacies as an example of sustained oral chemotherapeutic functionality.

Extraction, Structural Characterization, and Physicochemical and Biological Properties of Water-Soluble Polysaccharides from Adlay Bran.

Adlay bran, often discarded or used as animal feed, holds untapped potential. This study explores the beneficial properties of water-soluble polysaccharides (ABPs), extracted using a hot water method, with the aim of transforming what is commonly regarded as waste into a valuable resource. The response surface methodology (RSM) was employed to fine-tune the extraction parameters, establishing conditions at 80.0 °C, 2.5 h, and a water-to-material ratio of 31.6 mL/g. Structural studies showed that ABPs consist of different monosaccharides, including rhamnose, arabinose, glucosamine, glucose, galactose, xylose, mannose, and glucuronic acid, with respective molar ratios of 2.12%, 2.40%, 0.52%, 77.12%, 7.94%, 3.51%, 2.55%, and 3.82%. The primary component of these polysaccharides has a molecular weight averaging 12.88 kDa. The polysaccharides feature eight distinct linkage types: →3,4)-Rhap-(1→ at 5.52%, →4)-Glcp-(1→ at 25.64%, Glcp-(1→ at 9.70%, →3,4)-Glcp-(1→ at 19.11%, →4)-Xylp-(1→ at 7.05%, →3)-Glcp-(1→ at 13.23%, →3,4)-Galp-(1→ at 9.26%), and →4,6)-Gclp-(1→ at 12.49%. The semi-crystalline properties of ABPs and their shear-thinning characteristics were validated by X-ray diffraction and rheology tests. In vitro assays highlighted the strong antioxidant activities of ABPs, as evidenced by DPPH and ABTS hydroxyl radical scavenging tests, along with significant metal chelating and reducing powers. Additionally, ABPs showed significant inhibition of α-glucosidase and α-amylase, making them attractive as versatile additives or as agents with antioxidant and blood-sugar-lowering properties in both the food and pharmaceutical sectors. These findings support the utilization of adlay bran for higher-value applications, harnessing its bioactive components for health-related benefits.

Dose-dependent effect of cadaverine on hydroxyl radicals’ production by human peripheral blood leukocytes

Objective. To assess changes in the generation of hydroxyl radicals by leukocytes under the influence of cadaverine at concentrations of 1, 5 and 25 mmol/L. Materials and methods. Peripheral venous blood samples were obtained from 40 apparently healthy donors. To assess the production of hydroxyl radicals, a luminol-dependent chemiluminescence reaction with blood leukocytes, which were pre-incubated with cadaverine at concentrations of 1, 5 and 25 mmol/L was carried out. The study was conducted on a Luminoskan Ascent® Thermo Labsystems (USA) luminometer for 180 minutes. For statistical analysis, the integral chemiluminescence indicator for the entire measurement period (RLU) was used. The time to reach the maximum of light flashes in minutes, the intensity of the utmost glow, and the area under the luminescence extinction curve were calculated. Results. It was determined that pre-incubation of cells with cadaverine significantly reduces their time to reach the maximum generation of hydroxyl radicals. In addition, cadaverine enhances the intensity of the reaction of luminol-dependent chemiluminescence of leukocytes of healthy donors, and the greatest stimulating effect was recorded at a polyamine concentration of 5 mmol/L (p =0,009 to samples with a spontaneous reaction, p =0,007 and 0,010 to samples with cadaverine 1 mmol/L and 5 mmol/L respectively). Cadaverine increases the area under the reaction curve, it being the most significant at a concentration of 5 mmol/L – 20.89±3.00 c.u. versus 0.86±0.07 c.u. with a spontaneous reaction (p=0,001). Conclusions. The results of the study indicate a possible effect of cadaverine on the mechanisms of hydroxyl radical formation, as well as the activity of the diamine oxidase enzyme in leukocytes. It can be supposed that the combination of these effects contributes to the development of the environment favorable for microorganisms at the focus of inflammation. Thus, microorganisms that produce cadaverine, which modulates the generation of hydroxyl radicals by leukocytes, adapt to their environment, creating a special type of microenvironment, which probably results in an asymptomatic course of the inflammatory process.

Construction of S-scheme g-C3N4/PbTiO3 heterojunction and its highly efficient photocatalytic degradation of organic pollutants under simulated sunlight.

This study successfully synthesized a composite photocatalyst g-C3N4/PbTiO3 through hydrothermal and calcination methods using PbTiO3 and g-C3N4. The catalyst was characterized by XRD, FTIR, Raman, XPS, SEM, TEM, UV-vis DRS, PL, and other techniques. The results indicate that the composite photocatalyst exhibits efficient electron transfer, enhanced light absorption, effective separation and utilization of photogenerated electron-hole pairs, demonstrating superior photocatalytic activity. Under simulated sunlight, the removal efficiency of methyl blue (MB) with an initial concentration of 10mg/L reaches 93.0% after 120min. After five cycles, the degradation efficiency of MB is 79.2%, still maintaining 85% of the initial catalytic activity. The pH values in the range of 4.0-7.0, inorganic anions, and water quality have a minimal impact on the photocatalytic degradation of MB. Additionally, the composite photocatalyst exhibits strong removal capabilities for other pollutants, such as tetracycline. Therefore, the prepared catalyst demonstrates good feasibility for practical applications. Free radical quenching experiments indicate that hydroxyl radicals (·OH) are the primary active groups in the photocatalytic degradation of MB. Based on this, a photocatalytic mechanism involving a S-scheme heterojunction has been proposed. This study provides new insights into preparing PbTiO3 composite semiconductors and constructing novel S-scheme heterojunctions.

Secondary Organic Aerosol Formation during the Oxidation of Large Aromatic and Other Cyclic Anthropogenic Volatile Organic Compounds.

The secondary organic aerosol (SOA) production from the reactions of anthropogenic large volatile (VOCs) and intermediate volatility organic compounds (IVOCs) with hydroxyl radicals under high NO x conditions was investigated. The organic compounds studied include cyclic alkanes of increasing size (amylcyclohexane, hexylcyclohexane, nonylcyclohexane, and decylcyclohexane) and aromatic compounds (1,3,5-trimethylbenzene, 1,3,5-triethylbenzene and 1,3,5-tritert-butylbenzene). A considerable amount of SOA was formed from all examined compounds. For the studied cyclohexanes (C11-C16) there appears that the SOA yield depends nonlinearly on the length of their substitute chain. The large cyclohexanes had higher yields than the aromatic compounds, but the aromatic precursors produced a more oxidized SOA. This was due to the production of lower volatility and O:C first generation products by the cyclohexanes. Most oxidation products (with C* < 104 μg m-3) in the case of cyclohexanes are SVOCs (∼50%), while of aromatics are IVOCs (∼60%). Structure, molecular size, and length of the substitute chain of the parent hydrocarbon were found to play key roles in SOA formation, oxidation state, and volatility. The SOA volatility distribution, effective vaporization enthalpy, and effective accommodation coefficient were also quantified by combining SOA yields, thermodenuder (TD) and isothermal dilution measurements. Parameterizations for the Volatility Basis Set (VBS) are proposed for future use in chemical transport models.

Study of Exhaust Gas Composition and Dilution Effects on Diesel Spray Ignition Characteristics

ABSTRACT Exhaust gas retained in a cylinder is unavoidable, affecting diesel spray ignition. However, its effects on diesel spray ignition characteristics are not completely clear so far, due to the coupled and complicated function of exhaust gas compositions and dilution effects. To reveal the effect mechanism, three-dimensional simulations and chemical kinetics calculations were performed. The results illustrate that with the rise of exhaust gas rate, the initial position of the flame moves downward due to the longer ignition delay. The introduction of exhaust gas compositions decreases both the low-temperature and high-temperature ignition delay while dilution on oxygen mass fraction primarily affects and prolongs the high-temperature ignition delay. Nitric oxide (NO) significantly decreases the ignition delay compared to other exhaust gas compositions, with the high-temperature ignition delay experiencing a substantial decrease of 33.33% under 500 ppm NO addition at the ambient temperature of 820K. With the NO addition in the fresh intake air, conversion reactions occur between NO and nitrogen dioxide, and the reactions of NO with hydroperoxyl (HO2) and nitrogen dioxide with hydrogen radical lead to the generation of hydroxyl radical throughout the low- and high-temperature ignition stages, which enhances system reactivity and contributes to a decrease of ignition delay. The decrease in the oxygen mass fraction significantly reduces the rate of production of HO2 and hydrogen peroxide, which results in a decrease in the rate of production of hydrogen peroxide decomposition and HO2 deoxidation into hydroxyl radicals, prolonging the high-temperature ignition. The revealed mechanism may be applicable to the diagnosis of exhaust gas residual fault phenomenon.

Enhanced piezocatalytic RhB degradation with ZnSnO3 Nanocube-modified Bi4Ti3O12 composite catalyst by harnessing ultrasonic energy

With the increasing demand for effective methods to address environmental pollution, piezocatalysis has emerged as a promising approach for pollutant degradation under mechanical energy. However, the development of highly efficient piezocatalytic materials remains a challenge. This study aimed to increase the piezocatalytic activity of bismuth titanate (Bi4Ti3O12) by modifying it with zinc stannate (ZnSnO3) nanocubes. The composite catalysts were synthesized using a straightforward deposition and calcination process. The calcination process ensured the tight adhesion of ZnSnO3 nanocubes to the Bi4Ti3O12 surface, while facilitating strong interactions between ZnSnO3 and Bi4Ti3O12, which enhanced electron transfer and heterojunction structure formation. Band structure analysis indicated that Bi4Ti3O12 has higher conduction band and valence band potentials than ZnSnO3, forming a type-II heterojunction. Bi4Ti3O12 possesses a higher Fermi level than ZnSnO3, resulting in interfacial electron drift and formation of a built-in electric field, which further promotes the directional transfer and separation efficiency of charge carriers within the composite catalyst. This hypothesis was confirmed by surface photovoltage spectroscopy, piezoelectric current response, and electrochemical analysis. Consequently, the ZnSnO3/Bi4Ti3O12 composite exhibited significantly improved piezocatalytic performance in RhB degradation, achieving a degradation efficiency of 80 % within 90 min under ultrasonic vibration. The degradation rate of the optimal sample was 8.2 times that of Bi4Ti3O12 and 6.3 times that of ZnSnO3. Additionally, experiments to detect reactive species were conducted to elucidate the mechanism behind the piezocatalytic RhB degradation. Holes and hydroxyl radicals were the main reactive species. This study may offer new insights into the design of efficient piezocatalytic materials.

Synergistic surface ligand modification of Ni-Pt bimetallic nanozymes: Enhanced catalytic activity and versatile detection of penicillin

Monitoring and control of penicillin (PCN) in the environment are critically important for reducing the emergence and dissemination of antibiotic-resistant bacteria, ensuring food safety, and safeguarding human health. In this study, we introduce a novel and facile strategy for modulating the catalytic activity of bimetallic nanozymes through surface ligand engineering. Experimental activity assays and theoretical model calculations confirm that Ni-Pt nanozymes coated with polyallylamine hydrochloride (PAM) exhibit significantly enhanced peroxidase (POD)-like activity compared to their counterparts coated with conventional polyvinyl pyrrolidone (PVP) and polystyrene sulfonate (PSS). Leveraging the potent reactivity between PCN and the hydroxyl radicals (∙OH) generated by Ni-Pt@PAM catalytic system, we have developed a colorimetric sensor that directly detects PCN, demonstrating a linear response range from 0.5 to 10 μM and detection limit as low as 13.5 nM. Additionally, a fluorescent sensing platform utilizing self-synthesized fluorophore Rho-Si based on inner filter effect (IFE), has been successfully established. These two sensing platforms, capable of generating both colorimetric and fluorescent signals, enable sensitive, rapid, and straightforward detection of PCN in water samples. This work not only offers an innovative approach for tuning the POD-like activity of Ni-Pt bimetallic nanozymes but also presents a promising avenue for their application in PCN monitoring.

Gold nanoclusters stabilized with dopa-containing ligands: Catalyst-indicator integrated probe for tumor cell screening

Elevated hydrogen peroxide (H2O2) levels not only inflict cellular damage but also serve as a harbinger for various diseases. Tumor cells, in particular, often exhibit an abundance of H2O2. Hence, the detection of this pivotal molecule assumes paramount importance in monitoring physiological states and expediting cancer diagnosis. To this end, we have ingeniously devised an enzyme-free and monomeric system for intracellular H2O2 detection. Our astute selection of dopa-containing peptidomimetics, replete with ortho-bisphenol and amino acid moieties, has engendered the synthesis of distinctive fluorescent gold nanoclusters (AuNCs). These nanoclusters not only function as a peroxidase-like catalyst, catalyzing the decomposition of H2O2 into hydroxyl radicals (·OH), but also serve as an indicator, with their fluorescence quenched in response to varying H2O2 concentrations. Experimental results evince that our GDpE-AuNCs exhibit remarkable sensitivity, boasting a detection limit of 0.49 μM and a linear range of 5–1000 μM. Moreover, the amalgamation of catalyst and indicator within a single structure, facilitating efficient cellular uptake, engenders intracellular H2O2 detection and discernment of tumor cells. This pioneering approach bequeaths a valuable assay probe for monitoring physiological states and ushering in early disease diagnosis.

Hydrogen enrichment in methanol SI engine at varying injection timing during compression stroke

This study investigates the effect of hydrogen enrichment in a direct-injected methanol-fuelled SI engine, with combustion and emission performance analysed by varying the methanol injection timing from 150° to 60° CA bTDC. A three-dimensional computational fluid dynamic model of the hydrogen-enriched methanol engine was developed to predict the engine performance, in-cylinder, and emission characteristics. The numerical model was solved using three-dimensional Reynolds-Averaged Navier Stokes, the RNG k-epsilon model for turbulence, the O'Rourke and Amsden sub-model for heat transfer, the extended Zeldovich mechanism for nitric oxide emissions, and the Hiroyasu-NSC model for soot emissions. The results indicated that retarding the injection timing resulted in a decrease in the indicated specific CO and soot emissions along with a rise in the indicated specific NOx emissions. Furthermore, hydrogen enrichment with methanol enhanced the hydroxyl radical concentration, reduced the combustion duration, reduced also the indicated specific CO and soot emissions while increasing the indicated specific NOx emissions. The study indicates that hydrogen enrichment could extend the late injection timing limit of methanol by enhancing fuel-air mixing, which improves and controls the combustion process more effectively.

Covalent Labeling Automated Data Analysis Platform for High Throughput in R (coADAPTr): A Proteome-Wide Data Analysis Platform for Covalent Labeling Experiments.

Covalent labeling methods coupled to mass spectrometry have emerged in recent years for studying the higher order structure of proteins. Quantifying the extent of modification of proteins in multiple states (i.e., ligand free vs ligand-bound) can provide information on protein interaction sites and regions of conformational change. Though there are several software platforms that are used to quantify the extent of modification, the process can still be time-consuming, particularly for proteome-wide studies. Here, we present an open-source software for quantitation called Covalent labeling Automated Data Analysis Platform for high Throughput in R (coADAPTr). coADAPTr tackles the need for more efficient data analysis in covalent labeling mass spectrometry for techniques such as hydroxyl radical protein footprinting (HRPF). Traditional methods like Excel's Power Pivot (PP) are cumbersome and time-intensive, posing challenges for large-scale analyses. coADAPTr simplifies analysis by mimicking the functions used in the previous quantitation platform using PowerPivot in Microsoft Excel but with fewer steps, offering proteome-wide insights with enhanced graphical interpretations. Several features have been added to improve the fidelity and throughput compared to those of PowerPivot. These include filters to remove any duplicate data and the use of the arithmetic mean rather than the geometric mean for quantitation of the extent of modification. Validation studies confirm coADAPTr's accuracy and efficiency while processing data up to 200 times faster than conventional methods. Its open-source design and user-friendly interface make it accessible for researchers exploring intricate biological phenomena via HRPF and other covalent labeling MS methods. coADAPTr marks a significant leap in structural proteomics, providing a versatile and efficient platform for data interpretation. Its potential to transform the field lies in its seamless handling of proteome-wide data analyses, empowering researchers with a robust tool for deciphering complex structural biology data.

In situ treatment of contaminated soil using persulfate activated by sulfidated zero-valent iron

Soil contamination with hazardous substances like phenol poses significant environmental and health risks. In situ soil mixing can be a promising technological solution to this challenge. A persulfate and sulfidated zero-valent iron (S-ZVIbm) system for remediating contaminated soil was developed and tested to be suited to in situ soil mixing. S-ZVIbm was synthesized using a ball mill process, and the optimal sulfur to iron molar ratio for effectively removing phenol from soil removal without pyrophoric risks was 0.12. Soil slurry experiments were performed, and the best phenol oxidation results (high stoichiometric efficiency and sustained oxidation after mixing) were achieved at a persulfate to S-ZVIbm molar ratio of 2:1 and a persulfate to phenol molar ratio of 8:1. A high organic matter content of the silty clay fraction of the soil strongly suppressed persulfate activation, so suppressed phenol removal and increased persulfate consumption. Electron spin resonance and radical scavenging tests confirmed that hydroxyl and sulfate radicals were present during the degradation of phenol. While sulfate radicals predominantly facilitated degradation in the soil, both sulfate and hydroxyl radicals were crucial in the aqueous phase in the absence of soil organic matter. In situ soil mixing simulation tests indicated that the persulfate and S-ZVIbm doses and the mixing rate and duration strongly affected the efficacy of the system, and the optimal conditions for phenol removal were determined. The results indicated that the persulfate/S-ZVIbm system could be tuned to achieve sustained persulfate activation and to remediate contaminated soil employing in situ soil mixing technique.

Novel Catalyst-free Activation of Chlorine by Visible Light for Micropollutant Abatement

This study systematically investigated the direct activation of chlorine by visible light emitting diode (Vis-LED). Vis-LED could effectively activate chlorine to degrade micropollutants with degradation efficiency and pseudo-first-order degradation rate constant range of 64.3%-100% and 0.0340-0.195min-1, respectively. Quenching experiments and modeling results suggested that reactive chlorine species (RCS, including ClO•, Cl2•-, and Cl•) and hydroxyl radical (•OH) were involved in the degradation of atenolol (ATL). The contribution ratio of ClO•, free available chlorine, Cl•, Cl2•-, and •OH to ATL degradation were 58.7%, 17.4%, 15.6%, 1.8%, and 5.9%, respectively, in Vis-LED448/chlorine process. Moreover, the innate quantum yields of HClO and ClO- decreased from 0.229 and 0.0206 to 0.0489 and 0.0109mol·Einstein-1, respectively, as the wavelength increased from 448 to 513nm, leading to a decrease in ATL degradation, which was consistent with the model results. Experimental and modeling results have confirmed that ATL degradation decreased when pH increased from 4.0 to 9.0. Cl- had little effect on the degradation of ATL, while HA and HCO3- affected ATL degradation by scavenging reactive species and/or shielding effect. The concentration of disinfection by-products decreased with the increase of wavelength and pH. In summary, Vis-LED/chlorine is an efficient water treatment process even without a catalyst.

Enhanced Removal of Malachite Green from Wastewater Using Nonthermal Plasma Gliding Arc Discharge Combined with Ferrate Oxidation

The rapid and complete removal of Malachite Green (MG) dye was effectively achieved by combining potassium ferrate (Fe(VI)) treatment with nonthermal plasma discharge in both deionized water (DIW) and tap water (TW). This study evaluated the decolorization and mineralization efficiencies under varying MG concentrations, Fe(VI) dosages, and pH levels, as well as the impact of radical scavengers on the process. Fe(VI) alone resulted in moderate decolorization (35.01%) and low mineralization (21.46%) at an MG concentration of 50mg/L in DIW. Plasma discharge alone achieved mineralization rates of 20.6% in TW and 24.16% in DIW. While complete decolorization was observed for all initial MG concentrations, it required significantly longer treatment times (>30min). However, the combination of Fe(VI) with plasma (Fe(VI)-Plasma) demonstrated significant synergistic effects, achieving total decolorization and high mineralization rates -up to 92.5% in DIW and 88.7% in TW for 20mg/L MG- at much shorter treatment times. Radical scavenger tests revealed that hydroxyl radicals (OH) were the primary oxidants in MG degradation, followed by superoxide radicals and electrons. These findings suggest that the combined Fe(VI)-Plasma technology is a promising and efficient solution for dye removal, reducing both chemical usage and treatment time.