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The Baeyer–Villiger (B–V) oxidation of ketones to the corresponding lactones/esters is a classic and essential reaction in the chemical industry. However, this oxidation process has not yet been achieved in ambient conditions with the aid of oxygen and heterogeneous photocatalysts. In this study, we developed an organic photocatalytic system using covalent triazine/heptazine‐based frameworks (CTF‐TB/CHF‐TB) to enable the B–V oxidation reaction under mild conditions through a cascade reaction pathway. Experimental data and theoretical calculations showed that heptazine/triazine units can “chelate” and decompose the in situ generated H2O2 into hydroxyl radicals (⋅OH). Compared to conventional methods that primarily involve metal‐activated benzaldehyde at elevated temperatures (e.g., 60 °C), the ⋅OH generated in our study can readily cleave the C−H bond of benzaldehyde, forming an active intermediate that drives subsequent sequential processes: O2→H2O2→⋅OH→Ph‐CO⋅→Ph‐COOO⋅. By employing this photocatalytic process, a yield of 91 % and a selectivity of over 99 % were obtained in the oxidation of cyclohexanone to caprolactone at room temperature. This performance is comparable to the state‐of‐the‐art catalysts, and our CHF‐TB catalyst demonstrates impressive reusability, maintaining a high yield after 5 consecutive runs. This work presents a straightforward approach for C−H cleavage by organocatalysts to produce ϵ‐caprolactone in a mild manner by B–V oxidation. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) using hydroxyl radicals (•OH) as oxidizing agents are a promising technology. Herein, a feasible strategy is developed to initially construct carbazole‐based D‐π‐A type conjugated polymer (PBNCZ) via the oxidative coupling. Additionally, introducing ─COO− through Cyano hydrolysis extends its conjugated structure and improves the energy band structure, which greatly facilitates the generation of •OH as well as the enrichment of pollutants. Detailed experiments and theoretical calculations have proved that the introduction of ─COO− enhances the adsorption of O2 and bisphenol A (BPA), optimizing the reaction path of •OH. Thus, it completely decomposes 10 ppm of BPA within just 10 min, exceeding all previously organic photocatalysts. Meanwhile, the efficiency of photocatalytic H2O2 production by PBNCZ‐COO− reaches 1719.03 µmol h−1 g−1 under visible light. This multifunctional material with high adsorption capacity, photodegradation efficiency, and photocatalytic H2O2 production activity provides a solid foundation for the preparation of organic photocatalysts. [ABSTRACT FROM AUTHOR]

Advanced oxidation processes (AOPs) using hydroxyl radicals (•OH) as oxidizing agents are a promising technology. Herein, a feasible strategy is developed to initially construct carbazole‐based D‐π‐A type conjugated polymer (PBNCZ) via the oxidative coupling. Additionally, introducing ─COO− through Cyano hydrolysis extends its conjugated structure and improves the energy band structure, which greatly facilitates the generation of •OH as well as the enrichment of pollutants. Detailed experiments and theoretical calculations have proved that the introduction of ─COO− enhances the adsorption of O2 and bisphenol A (BPA), optimizing the reaction path of •OH. Thus, it completely decomposes 10 ppm of BPA within just 10 min, exceeding all previously organic photocatalysts. Meanwhile, the efficiency of photocatalytic H2O2 production by PBNCZ‐COO− reaches 1719.03 µmol h−1 g−1 under visible light. This multifunctional material with high adsorption capacity, photodegradation efficiency, and photocatalytic H2O2 production activity provides a solid foundation for the preparation of organic photocatalysts. [ABSTRACT FROM AUTHOR]

The lifetime of hydroxyl radicals (⋅OH) in the fuel cell catalyst layer remains uncertain, which hampers the comprehension of radical‐induced degradation mechanisms and the development of longevity strategies for proton‐exchange membrane fuel cells (PEMFCs). In this study, we have precisely determined that the lifetime of ⋅OH radicals can extend up to several seconds in realistic fuel cell catalyst layers. This finding reveals that ⋅OH radicals are capable of carrying out long‐range attacks spanning at least a few centimeters during PEMFCs operation. Such insights hold great potential for enhancing our understanding of radical‐mediated fuel cell degradation processes and promoting the development of durable fuel cell devices. [ABSTRACT FROM AUTHOR]

In conventional wastewater treatment plants, micropollutants mix with the aquatic environment because they cannot be removed entirely due to their nonbiodegradable structure. Advanced oxidation processes can be considered an alternative solution to this problem. In this study, five different pharmaceutical and personal care products, carbamazepine, diclofenac, ibuprofen, paracetamol, and triclosan, which are commonly found in aquatic environments, were selected as target pollutants. The removal of these target pollutants was investigated using advanced oxidation methods such as the Fenton and UV processes (UV, UV/H2O2, and UV/TiO2). The feasibility of processes in terms of cost was investigated. In the study, both initial and final pharmaceutical concentrations were measured using liquid chromatography mass spectrometry/mass spectrometry to accurately calculate removal efficiency. It has been determined that processes other than the UV process have removal efficiency >99.9%. The UV process showed removal efficiency of 40% for carbamazepine, 90% for diclofenac, 85% for ibuprofen, 86% for paracetamol and 85% for triclosan. Among the processes with high removal efficiency, the Fenton process has been integrated into wastewater treatment plants and has been shown to be the most suitable system in terms of both performance and cost in solving the micropollutant problem. [ABSTRACT FROM AUTHOR]

Type‐I photosensitizers (PSs) can efficiently generate reactive oxygen species (ROS) in the hypoxia condition of tumors, which show less oxygen dependence and are considered better candidates for photodynamic therapy (PDT). However, relatively few efficient type‐I organic PSs simultaneously generating two or more type‐I ROS under irradiation are reported. Herein, new alternate donor (D)‐acceptor (A) type molecules containing ladder‐type core (DA′D) fused with an electron‐deficient benzothiadiazole core are reported, which show symmetrical A‐DA′D‐A (QY1) and asymmetrical A‐DA′D‐A′′ (QY2) configurations, respectively. As these ROSs possess complementary properties of strong oxidizing ability (•OH) and long radical lifetime (O2•−), in vitro and in vivo experiments demonstrate that QY1 and QY2 show excellent PDT effects for tumor cells under normoxia or hypoxia, and can achieve remarkable tumor growth inhibition (TGI) rate of 90% for the QY2. More importantly, the generation of •OH in these PSs is revealed by experiments both in aqueous and in vitro, including the well‐known transformation of O2•− and direct electron transition from water to excited triplet PS. It thus provides a comprehensive understanding of the O2 dependence property of •OH radical and deep insights into the mechanism of type‐I PS. [ABSTRACT FROM AUTHOR]

Gold nanoparticles (AuNPs) are currently the most studied radiosensitizers in proton therapy (PT) applicable for the treatment of solid tumors, where they amplify production of reactive oxygen species (ROS). However, it is underexplored how this amplification is correlated with the AuNPs' surface chemistry. To clarify this issue, we fabricated ligand‐free AuNPs of different mean diameters by laser ablation in liquids (LAL) and laser fragmentation in liquids (LFL) and irradiated them with clinically relevant proton fields by using water phantoms. ROS generation was monitored by the fluorescent dye 7‐OH‐coumarin. Our findings reveal an enhancement of ROS production driven by I) increased total particle surface area, II) utilization of ligand‐free AuNPs avoiding sodium citrate as a radical quencher ligands, and III) a higher density of structural defects generated by LFL synthesis, indicated by surface charge density. Based on these findings it may be concluded that the surface chemistry is a major and underexplored contributor to ROS generation and sensitizing effects of AuNPs in PT. We further highlight the applicability of AuNPs in vitro in human medulloblastoma cells. [ABSTRACT FROM AUTHOR]

Biochar loaded with metal ions has been widely used to activate persulfate to degrade organic pollutants. However, the preparation conditions of catalysts are always controversial. In this study, the co‐heating conditions of soybean straw with high carbon and low nitrogen and nano‐iron oxide were systematically discussed by response surface method, and an efficient catalyst (Fe@BC) was obtained. Fe@BC can effectively activate sodium persulfate (PS) and degrade three synthetic azo dyes (Methyl orange (MO), Amino black 10B (AB10B), and Orange II) and rhodamine B (RhB). Under the optimum conditions, the removal rate of total organic carbon of these four dyes reached 41.1%–89.8% and the final degradation rate could reach 100%. The physicochemical properties of Fe@BC were studied by SEM, BET, XRD, XPS and TGA. The results revealed that the specific surface area of Fe@BC was 195.6m2/g. Further, reducing iron oxide by C generated C0.09Fe1.91 and zero‐valent iron. Free radical scavenging experiments and electron paramagnetic resonance (EPR) measurements showed that the main reactive oxide species (ROS) in the Fe@BC/PS system were hydroxyl radicals (•OH) and singlet oxygen (1O2). Finally, Several Fe@BC modification systems were explored, the optimum pH of Fe@BC/PS system was analyzed, and the effects of Fe@BC and PS dosage on degradation performance were also studied. This study provides a scientific basis for the production of efficient catalysts and biochar energy, and an effective treatment scheme for printing and dyeing wastewater. [ABSTRACT FROM AUTHOR]

Organic type‐I photosensitizers (PSs) which produce aggressive reactive oxygen species (ROS) with less oxygen‐dependent exhibit attractive curative effect for photodynamic therapy (PDT), as they adapt better to hypoxia microenvironment in tumors. However, the reported type‐I PSs are limited and its exacted mechanism of oxygen dependence is still unclear. Herein, new selenium‐containing type‐I PSs of Se6 and Se5 with benzoselenadiazole acceptor has been designed and possessed aggregation‐induced emission characteristic. Benefited from double heavy‐atom‐effect of selenium and bromine, Se6 shows a smaller energy gap (ΔEST) of 0.03 eV and improves ROS efficiency. Interestingly, type‐I radicals of both long‐lived superoxide anion (O2•‾) and short‐lived hydroxyl (•OH) are generated from them upon irradiation. This may provide a switch‐hitter of dual‐radical with complementary lifetimes for PDT. More importantly, simultaneous processes to produce •OH are revealed, including disproportionation of O2•‾ and reaction between excited PS and water. Actually, Se6 displays superior in–vitro PDT performance to commercial chlorin e6 (Ce6), under normoxia or hypoxia. After intravenous injection, a significantly in–vivo PDT performance is demonstrated on Se6, where tumor growth inhibition rates of 99% is higher than Ce6. These findings offer new insights about both molecular design and mechanism study of type‐I PSs. [ABSTRACT FROM AUTHOR]

Visible light‐driven photocatalysis has gained much attention due to its light‐harnessing characteristics and is extensively used in wastewater remediation. This paper presents a novel oxygen‐deficient manganese antimonate, MnSb2O6‐x, with a trirutile structure as an effective visible‐light‐driven photocatalyst for dye degradation. The synthesized samples were subjected to XRD, UV‐Vis DRS, SEM‐EDS, Raman, XPS, and PL analyses to study their physic chemical properties. The influence of sequential or single heating during the preparation method on the generation of oxygen vacancies is evaluated using UV‐Vis DRS, XPS, ESR, and Raman techniques. The oxygen‐deficient MnSb2O6 could achieve up to 85 % of MO degradation in 180 min under visible light irradiation, and its reusability up to six cycles was also investigated. In addition, the mechanism of dye degradation was supported with a scavenger test, and the degradation activities are correlated to the electron‐hole pair separation as convinced from the PL spectra. The simple and unique method of oxygen vacancy generation can inspire the development of antimonates with oxygen deficiencies, which have significant scope of application in environmental and energy conservation. [ABSTRACT FROM AUTHOR]

Cryptocaryon irritans causes one of the most serious diseases in various wild and cultured marine fish, leading to mass mortality and economic loss. In this study, hydroxyl radical (•OH) solution produced by strong ionization discharge combined with water jet cavitation effect was injected into orange‐spotted grouper (Epinephelus coioides) aquaculture tanks for C. irritans control. The results showed that all C. irritans theronts were inactivated by •OH solution at concentrations of 0.5 mg/L within 2 min. •OH could induce alteration of shape, the absence of motility and macronucleus dispersion in theronts. A possible explanation was that the macronucleus of C. irritans might be damaged by •OH; as a result, its metabolism and life activities were disturbed. The •OH treatment increased the survival rate of E. coioides challenged with C. irritans from 64.7 ± 8.0% (mean ± SD) to 100% and reduced their infection intensity significantly. Stress response biomarkers such as malonaldehyde, glutathione, glutathione peroxidase, superoxide dismutase (SOD) and catalase levels in the gills of E. coioides at different time points were analysed. The SOD activity in the •OH group first decreased and then recovered to the initial level at the end of the experiment. The other stress response biomarkers had no significant difference from that in the uninfected control group after •OH treatment. Additionally, the gill of E. coioides in the •OH group exhibited slight and reversible transformation compared with the uninfected control group. Compared with •OH treatment, chlorine dioxide and formalin treatment reduced the survival rate, induced oxidative damage and changed the histological gill structure in E. coioides. In conclusion, •OH could be applied effectively to control C. irritans infection without affecting the normal physiological condition of E. coioides. [ABSTRACT FROM AUTHOR]

The piezo‐Fenton system has attracted attention not only because it can enhance the Fenton reaction activity by mechanical energy input, but also because it is expected to realize a class of stimuli‐responsive advanced oxidation systems by regulating energy input and hydrogen peroxide self‐supply, thus greatly enriching the application possibilities of Fenton chemistry. In this work, a series of Fe‐doped g‐C3N4 (g‐C3N4‐Fe) as a piezo‐Fenton system were synthesized where the iron stably immobilized through Fe−N interaction. The piezo‐induced electrons generate on g‐C3N4 matrix support the conversion of Fe(III) to Fe(II) and promote rate‐limiting step of Fenton reaction. With the optimal Fe loading, g‐C3N4‐0.5Fe can achieve methylene blue (MB) degradation under ultrasonic treatment with first‐order kinetic rate constants of 75×10−3 min−1. Most importantly, the g‐C3N4‐Fe can maintain good catalytic activity in a wide pH range (pH=2.0∼9.0) and be cyclic used without iron leaching to solution (<0.001 μg ⋅ L−1), overcoming the disadvantage of traditional Fe‐based Fenton catalysts that can only be applied under acidic conditions and prone to secondary pollution. In addition, g‐C3N4‐0.5Fe also exhibits antibacterial properties of Escherichia coli and Staphylococcus aureus under ultrasound. Hydroxyl radicals mainly contribute to the degradation of MB and the sterilization process. Our work is an attempt to clarify the role of g‐C3N4‐Fe in the conversion of mechanical energy to ROS and provide inspirations for the piezo‐Fenton system design. [ABSTRACT FROM AUTHOR]

Photocatalysis is a promising technology for conversion of the glycerol into formic acid, but photocatalytic oxidation of C−C bonds in glycerol exhibits poor selectivity towards formic acid because the photogenerated radicals (e.g. hydroxyl radicals) further oxidize formic acid to CO2. In this work, a synergy of photogenerated holes and superoxide radicals that achieved the selective oxidation of glycerol into formic acid over the TiO2 catalyst was revealed. The charge separation of pristine TiO2 was improved with the aid of oxygen, which resulted in efficient hole oxidation of the C−C bonds in glycerol to formic acid. Surface active species were controlled to prevent being converted to hydroxyl radicals on TiO2 by controlling the oxygen and water contents, which solved the problem of formic acid peroxidation without sophisticated catalyst modifications. Mechanism studies suggested that glyceraldehyde and glycolaldehyde were the intermediates to generate formic acid. This work provides a green and efficient approach to produce formic acid as a liquid hydrogen carrier from bio‐based alcohols. [ABSTRACT FROM AUTHOR]

Defect pyrochlore‐type oxide, KGe0.5Te1.5O6 (KGTO) and its Ag+, Cu2+ and Sn2+ doped compositions were prepared by solid state and ion‐exchange methods respectively. The XRD results suggest that both parent KGTO and Ag+, Cu2+ and Sn2+ doped KGTO have crystallized in cubic lattice. The morphology of all compositions was obtained from SEM‐EDS and TEM‐SAED measurements. The textural properties were obtained from N2 adsorption‐desorption measurements. The FT‐IR and Raman spectra of all compositions are comparable. Surface elemental composition and electron‐hole recombination rate were deduced from XPS and PL measurements respectively. The photocatalytic performance of these materials was tested in the degradation of methylene blue (MB) and methyl orange (MO) dyes. The doping of Ag+, Cu2+ and Sn2+ into the KGTO lattice improved optical characteristics and photocatalytic activity significantly. Among the compositions investigated, Sn‐KGTO shown highest photocatalytic performance with 82 % for MB and 67 % for MO in 180 min. Trapping experiments were conducted to identify the active species participated in the MB degradation over Sn‐KGTO. The generation and participation of ⋅OH and O2−⋅ radicals were studied by terephthalic acid and potassium bromate experiments respectively. The reusability and chemical stability of Sn‐KGTO against MB degradation were also examined. A possible reaction mechanism was proposed to understand the MB degradation in the presence of Sn‐KGTO. [ABSTRACT FROM AUTHOR]

The importance of photolysis as an initiator of air chemistry outdoors is widely recognized, but its role in chemical processing indoors is often ignored. This paper uses recent experimental data to modify a detailed chemical model, using it to investigate the impacts of glass type, artificial indoor lighting, cloudiness, time of year and latitude on indoor photolysis rates and hence indoor air chemistry. Switching from an LED to an uncovered fluorescent tube light increased predicted indoor hydroxyl radical concentrations by ~13%. However, moving from glass that transmitted outdoor light at wavelengths above 380 nm to one that transmitted sunlight above 315 nm led to an increase in predicted hydroxyl radicals of more than 400%. For our studied species, including ozone, nitrogen oxides, nitrous acid, formaldehyde, and hydroxyl radicals, the latter were most sensitive to changes in indoor photolysis rates. Concentrations of nitrogen dioxide and formaldehyde were largely invariant, with exchange with outdoors and internal deposition controlling their indoor concentrations. Modern lights such as LEDs, together with low transmission glasses, will likely reduce the effects of photolysis indoors and the production of potentially harmful species. Research is needed on the health effects of different indoor air mixtures to confirm this conclusion. [ABSTRACT FROM AUTHOR]

Metal‐nitrogen‐carbon (M−N−C) materials display high catalytic activity for the oxygen reduction reaction (ORR) but poor durability which is considered to be related to the hydroxyl radicals (⋅OH) generated in‐situ. With reverse thinking, we try to increase the ⋅OH for the degradation of organic pollutants. In this study, the Fe−N−C catalyst was prepared by pyrolyzing the composite of tannin‐Fe film modified carboxylic CNT (TA−Fe‐CNT) and ZIF‐8. The ⋅OH generated during the ORR process was regulated by catalyst composition, applied potential, catalyst loading and pH. Under the optimum conditions, the Fe−N−C‐200 could degrade 86 % of methylene blue (MB) and reach a TOC removal rate of 21.2 % after 5 h through the heterogeneous electro‐Fenton (HEF) system. Overall, this study not only finds new application for M−N−C materials but also provides some useful information for improving their durability in proton exchange membrane fuel cell (PEMFC) from the opposite perspective. [ABSTRACT FROM AUTHOR]

Summary: The purpose of present research was to study novel antioxidant peptides from Golden melon seeds. Alkaline protease was used to hydrolyse the Golden melon seeds protein to obtain the hydrolysed peptides. These antioxidant peptides were purified and identified by ultrafiltration, gel filtration chromatography and RP‐HPLC‐ESI‐MS/MS. Results showed that the peptide fraction (GMSHp3) with molecular weight (MW) <3 kDa obtained by ultrafiltration had the highest antioxidant capacity. This fraction was further purified via gel filtration chromatography into six sub‐fractions, among which GMSHp3‐3 exhibited the highest hydroxyl radical scavenging effect. Fraction GMSHp3‐3 was further purified via RP‐HPLC‐ESI‐MS/MS and sequenced as six potential antioxidant peptides with amino acids sequences of RMSFPVMCRN, LMRVLAQLG, ALAPLVALPAA, LVGKPAPD, LPAAHKA and AHAAGYGG, among which LMRVLAQLG, LPAAHKA and AHAAGYGG possessed effective ferric reducing power. These results indicated that novel antioxidant peptides from golden melon seeds protein hydrolysates might be potential antioxidant source of functional foods or nutraceutical supplements. [ABSTRACT FROM AUTHOR]

Copper complexes are promising candidates for anticancer drugs, because of their redox properties and the ability to generate ROS (reactive oxygen species) in the cellular media. Most of the reported complexes with anticancer properties are based on Cu(II), which must be reduced to Cu(I) to exert the therapeutic action. Here, we report on the synthesis and characterization of two novel copper(I) complexes, a mononuclear complex [Cu(L1)2](ClO4) (1) and a binuclear helicate [Cu2(L2)2](ClO4)2(2) (L1=2‐ethoxy‐1,10‐phenanthroline, L2=1,2‐bis((1,10‐phenanthrolin‐2‐yl)oxy)ethane), which were designed to be structurally comparable, in order to evaluate the effect of nuclearity on the artificial nuclease activity. The activity of helicate (2) was higher than that of the monometallic (1), and the DNA cleavage mechanism is through the generation of hydroxyl radical in a Fenton‐like reaction, which occurs after oxidation of Cu(I) by O2. Also, helicate (2) showed a higher cytotoxic effect against different cancer cells lines, while both complexes are more active than cisplatin. [ABSTRACT FROM AUTHOR]

Electrochemical advanced oxidation processes (EAOPs), based on the in situ generation of the powerful oxidant, hydroxyl radical (.OH), have been developed for effective destruction of recalcitrant organic pollutants. Electrode materials used both as anode and cathode constitute one of the key parameters affecting the process efficiency. The electro‐Fenton (EF) process is one of the most powerful EAOPs in water/wastewater treatment. Inversely to other EAOPs, in the EF process,.OH can be generated both in the bulk solution (from reagents formed at the cathode) and on anode surface. Therefore, the role of anode/cathode couple is of great importance for this process. This study focuses on the comparative performance of ten electrodes (5 anodes, 5 cathodes) through more than fifty combinations during removal of the antibiotic p‐aminosalicylic acid (p‐ASA), taken as target pollutant. The following parameters were chosen for performance assessment: oxidative degradation kinetics, the time needed for complete destruction of p‐ASA, mineralization rate, mineralization current efficiency and energy consumption. The results obtained highlight the following sequence for the performance of anodes: BDD > PbO2 > Ti4O7 > Pt≈DSA, and that of cathodes: carbon sponge ≥ carbon felt > graphite > stainless steel≈titanium. [ABSTRACT FROM AUTHOR]

The development and investigation of materials that leverage unique interfacial effects on electronic structure and redox chemistry are likely to play an outstanding role in advanced technologies for wastewater treatment. Here, the use of surface functionalization of metal oxides with a RuIIpoly(pyridyl) complex was reported as a way to create hybrid assemblies with optimized electrochemical performance for water remediation, superior to those that could be achieved with the molecular catalyst or metal‐oxide electrodes used individually. Mechanistic analysis demonstrated that the molecularly functionalized electrodes could suppress the formation of hydroxyl radicals (i. e. the dominant remediation pathway for bare metal‐oxide electrodes), allowing the water remediation to proceed through the highly oxidizing Ru3+ ions in the surface‐bound complexes. Furthermore, the underlying metal‐oxide substrates played a crucial role in altering the electronic structure and electrochemical properties of the surface‐bound catalyst, such that the competing side reaction (i. e. water splitting) was largely inhibited. [ABSTRACT FROM AUTHOR]

Hydrogen peroxide plays an important role as an intermediate and product in the reduction of dioxygen by copper enzymes and mononuclear copper complexes. The copper(II) tris(2‐pyridylmethyl)amine complex (Cu‐tmpa) has been shown to produce H2O2 as an intermediate during the electrochemical 4‐electron reduction of O2. We investigated the electrochemical hydrogen peroxide reduction reaction (HPRR) by Cu‐tmpa in a neutral aqueous solution. The catalytic rate constant of the reaction was shown to be one order of magnitude lower than the reduction of dioxygen. A significant solvent kinetic isotope effect (KIE) of 1.4 to 1.7 was determined for the reduction of H2O2, pointing to a Fenton‐like reaction pathway as the likely catalytic mechanism, involving a single copper site that produces an intermediate copper(II) hydroxo species and a free hydroxyl radical anion in the process. [ABSTRACT FROM AUTHOR]

In this study, the degradation of caffeine was investigated by UV/Fe2+/persulfate (PS) process. Caffeine (CAF) degradation in sole‐UV, UV/Fe2+, UV/PS, and Fe2+/PS systems was also conducted to examine the contribution of isolated processes to CAF degradation. The effects of pH levels, the concentration of Fe2+ and PS, inorganic anions, and initial concentration of CAF on the performance of UV/Fe2+/PS process were evaluated. Radical competitive reactions indicated both hydroxyl radicals and sulfate radicals played important roles in CAF degradation in UV/Fe2+/PS system. Nine intermediates, among which three were detected for the first time, were identified by ultra‐performance liquid chromatography/electrospray‐time‐of‐flight mass spectrometry (UPLC/ESI‐TOF‐MS) and SPME (solid‐phase microextraction)/GC/MS. The possible degradation pathways of CAF were proposed, among which demethylation, hydroxylation, the oxidation of olefinic double bond, and the cleavage of pyrimidine ring and imidazole ring were involved in the degradation of CAF in UV/Fe2+/PS system. Practitioner points: Caffeine degradation by UV/Fe2+/PS process was investigated.Caffeine degradation did not follow a simple pseudo‐first order kineticsChloride ions promoted CAF degradation.The anions NO3−, SO42−, and H2PO4− exerted a negative influence on caffeine degradation.Nine intermediates were detected, and decay pathways were proposed. [ABSTRACT FROM AUTHOR]

This contribution aims at developing engineering approaches to characterize radiative transfer and kinetics of a catalyst to be activated by electromagnetic radiation, one of the main bottlenecks when evaluating materials in heterogeneous photocatalytic processes. A specialized LED‐based photoreactor is engineered to obtain reliable information on the aforementioned mechanisms. The radiative transfer approach serves as a criterion to elucidate the capability of a catalyst to be activated or not by visible light or UV‐A light. When the catalyst favours the absorption of photons rather than their scattering or transmission, the experimental methodology allows the determination of intrinsic optical information being independent of fluid dynamics, and catalyst concentration. Radiative characterization, along with a mass transfer analysis, guides the proposal of the operational design of the photoreactor to carry out intrinsic kinetic studies. Thus, the operation of the photoreactor under pseudo‐isoactinic and differential reaction conditions leads to the determination of intrinsic initial reaction rates, enabling the understanding of the complex interaction among the optical properties of the catalyst, the reaction rate for the production of hydroxyl radicals (•OH), and the oxidation of a recalcitrant organic pollutant. The procedures assessed are worthy of being used for evaluating other materials, activated at different wavelength ranges or designed for different photocatalytic applications, paving the way for the scale‐up of the reactor, another of the main challenges in photocatalysis. [ABSTRACT FROM AUTHOR]

Reactive oxygen species (ROS) containing sulfate and hydroxyl radicals can act as Fenton type reagents to remove organic contaminants from water. Here, a catalytic system silver metavanadate is reported for the activation of peroxodisulfate in an aqueous medium to generate ROS, which is further utilized for the efficient degradation of the water‐soluble pollutants such as phenols, pesticides, antibiotics, and organic dyes. Remarkably, complete carbon mineralization of the water‐soluble contaminants is achieved to form carbon dioxide as the major product. In‐situ electron paramagnetic resonance (EPR) studies combined with ex‐situ methods reveal that a massive amount of hydroxyl radicals (•OH) are formed through sulfate radical anions (SO4•−) and act as the ROS for the organic pollutant degradation. In addition, the stability of the catalyst is monitored by various characterization techniques. [ABSTRACT FROM AUTHOR]

BACKGROUND In the present study, the Fenton process was used as an effective method to treat several contaminants present in wastewaters. The case study is a pig farm located in the community of Loma de Zempoala, Guanajuato, Mexico, where the Fenton process in continuos flow assisted with sunlight was used to treat a real piggery wastewater. RESULTS: First, an optimization of the operational parameters at laboratory scale was carried out by experimental design Taguchi L9. Experimental data showed the following degradation efficiencies: chemical oxygen demand (COD) = 95% ± 1.%; total organic carbon (TOC) = 53% ± 9%; Color = 99% ± 1%. To maximize the degradation of organic matter a Response Surface Methodology (RSM) was employed to define the following operational parameters: pH = 3, reaction time = 60 min, molar ratios hydrogen peroxide (H2O2):COD = 1.5 and H2O2:ferrous ion (Fe2+) = 1.5. As a second step, the scaling of the process in continuous flow was carried out, and the experimental data were adjusted appropriately to a kinetic model of pseudo‐first‐order, reaching a 98% degradation of organic matter at 250 min. CONCLUSION: In this study, the Fenton process assisted with sunlight is faster than the traditional method because the incident light has a catalytic effect together with the ferric ion, improving the formation of hydroxyl radicals; as a consequence, the treated effluent presents the quality indicated by the Mexican environmental legislation. © 2020 Society of Chemical Industry (SCI) [ABSTRACT FROM AUTHOR]

Power conversion efficiencies (PCEs) of polymer solar cells (PSCs) have exceeded 18% in the last few years. Stability has therefore become the next most important issue before commercialization. Herein, the degradation behaviors of the inverted PM6:IT‐4F (PBDB‐T‐2F:3,9‐bis(2‐methylene‐((3‐(1,1‐dicyanomethylene)‐6,7‐difluoro)‐indanone))‐5,5,11,11‐tetrakis(4‐hexylphenyl)‐dithieno[2,3‐d:2′,3′‐d′]‐s‐indaceno[1,2‐b:5,6‐b′]dithiophene) solar cells with different ZnO layers are systematically investigated. The PCE decay rates of the cells and the photobleaching process of the IT‐4F containing organic films on ZnO surface are directly correlated with the light‐absorption ability of the ZnO layer in the visible light range, indicating that photochemical decomposition of IT‐4F is initiated by the light absorption of ZnO layer. By analyzing the products of the aged ZnO/IT‐4F films with matrix‐assisted laser desorption ionization time‐of‐flight mass spectrometry (MALDI‐TOF‐MS), it is confirmed that photochemical reactions at the IT‐4F/ZnO interface include de‐electron‐withdrawing units and dealkylation on the side‐phenyl ring. Hydroxyl radicals generated by the photo‐oxidation of dangling hydroxide by ZnO are confirmed by electron spin resonance (ESR) spectroscopy measurements, which is attributed as the main reason causing the decomposition of IT‐4F. Surface treatment of ZnO with hydroxide and/or hydroxyl radical scavenger is found to be able to improve the stability of the PSCs, which further supports the proposed degradation mechanism. [ABSTRACT FROM AUTHOR]

Laser‐induced fluorescence was used to determine the absolute OH density in a pulse‐modulated atmospheric‐pressure surface microdischarge in helium. Measurements were carried out during the discharge and post‐discharge in both plasma layer and downstream region. Experimental findings show that dissipated power, modulation on‐time duration, and the distance from the dielectric surface have more significant effects on the OH(X) lifetime than OH(X) density. The lifetime dependence on power is more pronounced as compared with the modulation duration. Moreover, a dielectric barrier discharge model was presented to estimate the density evolution and loss mechanisms of OH radicals. The results indicate that the decay of OH density is mainly due to the transport process and recombination reactions. [ABSTRACT FROM AUTHOR]

Fascinating oscillations of color, kinetics of pH, cyclic voltammetry (CV) and UV‐vis spectra, ensued from supplementing of VO(acac)2‐acetonitrile solutions with micro‐amounts of H2O2, were greatly affected by the small additives of glyoxal and oxalic acid. Such effect was consisted in sufficient decreasing the sensitivity of samples by means of it pH, CV and UV‐vis response onto H2O2 additives. The revealed peculiarities substantiate the responsibility of free radicals (particularly.OH generated in the course of H2O2 homolysis) for the discussed parameters alteration. In view of.OH are identified as most active and destructive (especially, in respect to the cellular constituents) agents can be originated in vivo, it overproduction is responsible for developing of many related severe diseases. In practical aspect the undertaken research may be recommended for the oxidative stress evaluation and tracking. [ABSTRACT FROM AUTHOR]

Radiation‐induced cleavage for controlled release in vivo is yet to be established. We demonstrate the use of 3,5‐dihydroxybenzyl carbamate (DHBC) as a masking group that is selectively and efficiently removed by external radiation in vitro and in vivo. DHBC reacts mainly with hydroxyl radicals produced by radiation to afford hydroxylation at para/ortho positions, followed by 1,4‐ or 1,6‐elimination to rescue the functionality of the client molecule. The reaction is rapid and can liberate functional molecules under physiological conditions. This controlled‐release platform is compatible with living systems, as demonstrated by the release of a rhodol fluorophore derivative in cells and tumor xenografts. The combined benefits of the robust caging group, the good release yield, and the independence of penetration depth make DHBC derivatives attractive chemical caging moieties for use in chemical biology and prodrug activation. [ABSTRACT FROM AUTHOR]

As an emerging member of the graphene family, structurally defined graphene nanoribbons (GNRs) have shown promising applications in various fields. The evaluation of the degradability of GNRs is particularly important for assessing the persistence level and risk of these materials in living organisms and the environment. However, there is a void in the study of the degradation of GNRs. Here, we report the degradation behavior of GNRs in the presence of human myeloperoxidase (hMPO) or treated with the photo‐Fenton (PF) reaction. With the assistance of potassium hydroxide or imidazole, which facilitates the dispersion of GNRs in the aqueous solution, GNRs underwent only partial degradation after 25‐hour incubation with hMPO, while, the PF reaction degraded GNRs almost completely after 120 hours. These results indicate that structurally precise GNRs can be efficiently degraded under suitable conditions, providing more opportunities for future applications in different fields. [ABSTRACT FROM AUTHOR]

Generation of hydroxyl radicals in the Fenton system (FeII/H2O2) is seriously limited by the sluggish kinetics of FeIII reduction and fast FeIII precipitation. Here, boron crystals (C‐Boron) remarkably accelerate the FeIII/FeII circulation in Fenton‐like systems (C‐Boron/FeIII/H2O2) to produce a myriad of hydroxyl radicals with excellent efficiencies in oxidative degradation of various pollutants. The surface B−B bonds and interfacial suboxide boron in the surface B12 icosahedra are the active sites to donate electrons to promote fast FeIII reduction to FeII and further enhance hydroxyl radical production via Fenton chemistry. The C‐Boron/FeIII/H2O2 system outperforms the benchmark Fenton (FeII/H2O2) and FeIII‐based sulfate radical systems. The reactivity and stability of crystalline boron is much higher than the popular molecular reducing agents, nanocarbons, and other metal/metal‐free nanomaterials. [ABSTRACT FROM AUTHOR]

A heterogeneous NiO catalyst was prepared by a precipitation process using nickel nitrate with oxalic acid and tested for heterogeneous oxidation of benzoic acid (BA) in the presence of peroxymonosulfate (PMS). It was found that the synthetic NiO is highly effective in heterogeneous activation of PMS to produce sulfate radicals (SO4·-) and hydroxyl radicals (·OH), and also presents stable performance in the heterogeneous activation of PMS for BA degradation. Physicochemical properties of the NiO catalyst were characterized by several techniques, such as thermogravimetric analysis, Brunauer‐Emmett‐Teller, Fourier transform infrared spectroscopy, X‐ray diffraction, X‐ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. It was found that NiO and NiOOH were formed on the synthetic NiO catalyst and were stably distributed on the catalyst surface. Nearly 95% decomposition could be achieved in 30 min at the conditions of 500 ml 20 μM BA solution, 0.25 g catalyst, and [PMS]:[BA] = 30:1. The heterogeneous reactions, the effects of PMS concentration, and catalyst dosage on the BA degradation were investigated. The heterogeneous BA degradation reactions followed first‐order kinetics. Additionally, quenching experiments proved that the dominant radical in the solution was ·OH. The experiments results also showed that this approach is effective for the degradation of many other pollutants (such as tetracycline hydrochloride, 2, 4‐dichlorophenol, Acid orange 7, rhodamine B, and methyl red). Practitioner points: A novel NiO material was fabricated for degradation of benzoic acid.The synthetic NiO catalyst comprised active NiO and NiOOH.The main radical for benzoic acid removal rate was ·OH.A plausible mechanism for catalyzed degradation of the benzoic acid was proposed. [ABSTRACT FROM AUTHOR]

Bio‐electro‐Fenton processes use biological electrons produced from bioelectrochemical systems to treat wastewater. The most significant advantages of bio‐electro‐Fenton systems are high effectiveness, low toxicity, gentle operation conditions, environmentally friendly treatment without sludge accumulation and energy conservation. Though promising, bio‐electro‐Fenton systems still face several challenges, such as high power density, H2O2 concentration, cathode materials, Fe2+ concentration and pH. This review comprehensively discusses the mechanisms of bio‐electro‐Fenton systems. Then, structural configurations are critically reviewed, including microbial fuel cells coupled with electro‐Fenton systems, microbial electrolysis cells coupled with electro‐Fenton systems and other bioelectrochemical systems coupled with electro‐Fenton systems. Furthermore, recent advances in bio‐electro‐Fenton systems for wastewater treatment are introduced, including dye solution, pharmaceuticals and personal care products, oily wastewater, landfill leachate and other pollutants. In addition, the current challenges and specific future prospects of bio‐electro‐Fenton, such as possible mechanisms for improving the power output, electrode materials that are potentially useful, self‐designed electrodes and methods of maintaining circumneutral pH values, are also explored. Heretofore, great progress in bio‐electro‐Fenton has been made, but further improvements are still needed in order to make this system more economical and practical. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Energy crises and environmental pollution have sparked tremendous research work to handle their impacts. Herein, we fabricated Au/g‐C3N4 nanocomposites to produce H2 and degrade 2,4‐dichlorophenol (2,4‐DCP) under visible light and at different wavelengths. Interestingly, the optimized photocatalyst generated 114 μmol H2 and degraded 25% 2,4‐DCP in 1 hr as compared with 10 μmol H2 generation and 8% 2,4‐DCP degradation by pure g‐C3N4. This improvement is credited to the extended light absorption and improved charge induction from gold to g‐C3N4 even at 590 nm as confirmed from photoluminescence, surface photovoltage, and photoelectrochemical study of the samples. Moreover, the surface catalytic property of g‐C3N4 was much improved after loading a proper amount of gold nanoparticles. We hope that this technique to photosensitize semiconductors with noble metal nanoparticles may provide a feasible way to construct surface plasmon resonance‐assisted photocatalysts to cope with energy crises and environmental pollution simultaneously. [ABSTRACT FROM AUTHOR]

Two atmospherically relevant dihalogenated methylperoxy radicals CHX2OO. (X=F and Cl) have been generated through O2‐oxidation of the corresponding alkyl radicals CHX2. in the gas phase. The IR spectroscopic characterization of both radicals in cryogenic Ar‐ and N2‐matrices (15 K) is supported by 18O‐labeling and ab initio calculations at the UCCSD(T)/aug‐cc‐pVTZ level. Upon 266 nm laser irradiation, both radicals decompose mainly by releasing hydroxyl radicals (→HO.+X2CO) via the intermediacy of intriguing α‐hydroperoxyalkyl radicals (.CX2OOH), implying that the photooxidation of dihalogenated hydrocarbons might serve as important sources of HO. radicals in the atmosphere. [ABSTRACT FROM AUTHOR]

BACKGROUND: This study investigates a novel, efficient and green pretreatment approach using ferrous iron catalyzed peracetic acid oxidation (Fe2+/PAA) on anaerobic fermentation of waste activated sludge. The underlying mechanisms are also studied for both the chemical and microbial effects. RESULTS: The results indicate that Fe2+/PAA exhibit significant positive synergistic effect on short‐chain fatty acid (SCFA) generation, especially acetic acid. The maximal SCFA concentration of 272 mg COD g−1 VSS is obtained with Fe2+ (2.7 mmol L–1)/PAA (3.0 mmol L–1), which is 5.2 times that of the control test. Fe2+/PAA can effectively facilitate sludge solubilization due to the disruption of extracellular polymeric substances structure and microbial cells. The biodegradability of released organic substance is also improved due to the oxidation of non‐biodegradable substances. The activity of functional enzymes for hydrolysis and acidification is enhanced but that for methanogenesis is inhibited. Further analysis on microbial community structure indicates that phylum Firmicutes and genera Proteiniclasticum showed the maximal positive correlation with SCFA production, while the abundance of methanogenic archaea especially acetoclastic methanogenic archaea is inhibited by Fe2+/PAA treatment. Moreover, the presence of Fe2+ lengthened the oxygen release period of PAA, the main functional reactive oxygen species are hydroxyl radicals and Fe2+ facilitated PAA generates more hydroxyl radicals thus enhancing the oxidation ability of PAA. CONCLUSION: This study demonstrated that Fe2+/PAA can be used as an effective pretreatment method for SCFA accumulation in sludge anaerobic fermentation process. The findings obtained in this study will supply information for the application of Fe2+ catalyzed PAA pre‐oxidation in sludge treatment. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Two atmospherically relevant dihalogenated methylperoxy radicals CHX2OO. (X=F and Cl) have been generated through O2‐oxidation of the corresponding alkyl radicals CHX2. in the gas phase. The IR spectroscopic characterization of both radicals in cryogenic Ar‐ and N2‐matrices (15 K) is supported by 18O‐labeling and ab initio calculations at the UCCSD(T)/aug‐cc‐pVTZ level. Upon 266 nm laser irradiation, both radicals decompose mainly by releasing hydroxyl radicals (→HO.+X2CO) via the intermediacy of intriguing α‐hydroperoxyalkyl radicals (.CX2OOH), implying that the photooxidation of dihalogenated hydrocarbons might serve as important sources of HO. radicals in the atmosphere. [ABSTRACT FROM AUTHOR]

A facile approach for dendrimer stabilized gold nanoparticles and their application in the generation of hydroxyl radicals has been developed. Dendrimer stabilized AuNP‐1 exhibits more efficient catalytic activity than triehylene glycol stabilized AuNP‐2 in the generation of hydroxyl radicals, and further oxidized methylene blue (MB) to MB‐OH. In addition, the AuNP‐1 induced •OH generation is more notable at neutral pH than at the basic or acidic pH level. [ABSTRACT FROM AUTHOR]

This study demonstrates that the gradual and slow production of initiating radicals (i.e., hydroxyl radicals here) is the key point for the synthesis of ultra‐high molecular weight (UHMW) polymers via controlled radical polymerization. Hydrogen peroxide (H2O2) and ferrous iron (Fe2+) react via Fenton redox chemistry to initiate RAFT polymerization. This work presents two enzymatic‐mediated (i.e., Bio‐Fenton‐RAFT and Semi Bio‐Fenton‐RAFT) and one syringe pump‐driven Fenton‐RAFT polymerization processes in which the initiating radicals are carefully and gradually dosed into the reaction solution. The "livingness" of the synthesized UHMW polymers is demonstrated by chain extension and aminolysis experiments. Zimm plots obtained from static light scattering (SLS) technique are used to characterize the UHMW polymers. This Fenton‐RAFT polymerization provides access to polymers of unprecedented UHMW (Mw ~ 20 × 106 g mol−1) with potential in diverse applications. The UHMW polymers made via the controlled Fenton‐RAFT polymerization by using a syringe pump shows that it is possible to produce such materials through an easy‐to‐set up and scalable process. © 2019 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2019, 57, 1922–1930 [ABSTRACT FROM AUTHOR]

Development of an efficient and economic NO oxidation technology is the key step for the simultaneous removal of NOx and SO2 in coal‐fired power plants. In this work, a novel advanced oxidation process of NO was proposed, which directly delivered highly oxidative hydroxyl radicals (·OH) generated from the thermal activation of H2O2 vapour into flue gas flow. The experiments were demonstrated in a lab‐scale device, measuring the oxidation of NO as the indicator of radical formation and delivery. The influence of various operational parameters on NO oxidation was evaluated. Increasing the H2O2 dosage, the temperature of the hot‐nitrogen, the flow rate of the hot‐nitrogen, and the total gas residence time greatly enhances the NO oxidation. The NO oxidation was inhibited obviously with the increasing of the H2O2 pH and the NO initial concentration. Increasing the H2O2 pH and the NO initial concentration obviously reduced the NO oxidation. The results indicated that the thermal activation of H2O2 is feasible to oxidize NO and that the H2O2 homogeneous thermal decomposition reaction is essential, therefore, the temperature and the flow rate of the hot‐nitrogen can significantly affect the conversion efficiency. Finally, a potential application was proposed, where NO oxidation by gas‐phase H2O2 can be coupled with the general SCR system to meet stringent regulatory requirements and with a low operating cost. [ABSTRACT FROM AUTHOR]

BACKGROUND Anodic oxidation, a promising approach for the removal of refractory organic pollutants in wastewater through advanced oxidation, still faces the challenge of high energy consumption. This study coupled an O2‐reducing biocathode, a cathode thermodynamically more favorable than conventional abiotic ones, with an MnOx/Ti electrocatalytic porous anode, to produce a novel biocathode–electrocatalytic reactor (BECR). RESULTS: After inoculation, the BECR was successfully started up to generate current at a voltage of 0.7 V, which was lower than the startup voltages of electrocatalytic reactors with abiotic cathodes. The cathode potential of the BECR was increased by approximately 300 mV. Abundant electrochemically active microorganisms were found on the BECR cathode with Pseudomonas and Acinetobacter as the dominant genera reducing O2 to H2O. Furthermore, hydroxyl radical (·OH) generation was detected in the anode chamber of the BECR after startup at 0.7 V and contributed to its current production. This phenomenon was not observed for electrocatalytic reactors. The mechanism of the BECR in reducing the applied voltage to generate ·OH was well elucidated using the thermodynamic theory of Gibbs free energy. CONCLUSIONS: The coupling of the O2‐reducing biocathode improved the thermodynamics of the BECR cathode toward a high redox potential and consequently reduced its applied voltage to generate ·OH, thereby rendering it as potentially energy saving and suitable for use in wastewater treatment. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Organic aerosol (OA) is chemically dynamic, continuously evolving by oxidative chemistry, for instance, via hydroxyl radical (OH) reactions. Studies have explored this evolution (so‐called OA aging) in the atmosphere, but none have investigated it indoors. Aging organic molecules in both particle and gas‐phases undergo changes in oxygen content and volatility, which may ultimately either enhance or reduce the condensed‐phase OA concentration (COA). This work models OH‐induced aging using the two‐dimensional volatility basis set (2D‐VBS) within an indoor model and explores its significance on COA relative to prior modeling methodologies which neglect aging transformations. Lagrangian, time‐averaged, and transient indoor simulations were conducted. The time‐averaged simulations included a Monte Carlo procedure and sensitivity analysis, using input distributions typical of U.S. residences. Results demonstrate that indoors, aging generally leads to COA augmentation. The extent to which this is significant is conditional upon several factors, most notably temperature, OH exposure, and OA mass loading. Time‐averaged COA was affected minimally in typical residences (<5% increase). However, some plausible cases may cause stronger COA enhancements, such as in a sunlit room where photolysis facilitates significant OH production (~20% increase), or during a transient OH‐producing cleaning event (~35% peak increase). [ABSTRACT FROM AUTHOR]

It is highly desired to synthesize low‐cost photocatalysts for the degradation of colored dyes to safeguard our environment for the future generations. Here, we report an extremely efficient and low‐cost synthesis of alkaline earth and transition‐metal ferrite photocatalysts (MgFe2O4, CaFe2O4, BaFe12O19, CuFe2O4, and ZnFe2O4) from their chloride salts and their applications for the degradation of methylene blue (MB) dye under UV–visible and direct sunlight irradiation. The as‐prepared photocatalysts displayed enhanced photoactivities under both conditions of irradiation. After calcination at 600°C, the photocatalytic degradation increased significantly, and 96 and 85% MB was removed with ZnFe2O4 under UV–visible and direct sunlight irradiation, respectively. Moreover, large amounts of hydroxyl free radicals were produced under both irradiation conditions, which participated in the degradation of MB. The enhanced photodegradation activities of these photocatalysts are attributed to their extended visible light absorption and low bandgaps. This work will provide a feasible route to the synthesis of efficient and low‐cost photocatalysts to utilize sunlight for environmental remediation. Highly efficient metal ferrite nanophotocatalysts are prepared by a simple precipitation method. The excellent degradation efficiency for methylene blue has been attributed to the hydroxyl free radicals. This work shows that these nanophotocatalysts can be used for the degradation of pollutants under direct sunlight irradiation. [ABSTRACT FROM AUTHOR]

Depression is intimately linked with oxidative stress. As one of the most reactive and oxidative reactive oxygen species that is overproduced during oxidative stress, the hydroxyl radical (.OH) can cause macromolecular damage and subsequent neurological diseases. However, due to the high reactivity and low concentration of.OH, precise exploration of.OH in brains remains a challenge. The two‐photon fluorescence probe MD‐B was developed for in situ.OH imaging in living systems. This probe achieves exceptional selectivity towards.OH through the one‐electron oxidation of 3‐methyl‐pyrazolone as a new specific recognition site. MD‐B can be used to map.OH in mouse brain, thereby revealing that increased.OH is positively correlated with the severity of depression phenotypes. Furthermore,.OH has been shown to inactivate deacetylase SIRT1, thereby leading to the occurrence and development of depression phenotypes. This work provides a new strategy for the future treatment of depression. Shedding light on depression: A novel two‐photon fluorescent probe was developed for imaging.OH in living cells and in vivo. The probe was successfully used to trace.OH levels in the brains of mice with depression phenotypes for the first time. [ABSTRACT FROM AUTHOR]

Two catalysts, carbon doped TiO2 (C‐TiO2) and C‐TiO2 conjugated with reduced graphene oxide (rGO)–C‐TiO2/rGO were synthesized and compared with respect to the photocatalytic hydrogen (H2) production using three organic fatty acids (OFAs) as electron donors under visible light irradiation. Our results show that the hybridization between C‐TiO2 and rGO did not subtaintially improve the production of H2 but instead elicited inhibitory effects compared to C‐TiO2. For instance, the specific H2 production on C‐TiO2 was 214 and 336 μmol·h−1·g−1 for acetic and propionic acids, respectively, whereas C‐TiO2/rGO only achieved 155 and 161 μmol·h−1·g−1, respectively. With butyric and lactic acids as electron donors, C‐TiO2 and C‐TiO2/rGO led to almost the same H2 production rates (233 and 155 μmol·h−1·g−1, respectively). The inhibitory effect of rGO on photocatalytic activity could be due to the potential deposition of OFAs on graphene sheets that may reduce the mobility and accessibility of OFAs toward catalytic reactions with C‐TiO2. The electron spin resonance spectrometry (ESR) tests revealed that O2·− and CH3• were the major radicals responsible for OFA degradation. Moreover, the produced concentration of CH3• was consistently higher in C‐TiO2 suspension than that in C‐TiO2/rGO suspension. The estimated aqueous/solid mass transfer rate constant (s−1) was lower on the catalyst surface of C‐TiO2/rGO than C‐TiO2. Consequently, the decoration of rGO sheets on C‐TiO2 may not always promote photocatalytic H2 production especially when using OFAs as electron donors. The results demonstrated hereby aim to provide new evidence on potential drawbacks of graphene‐based photocatalysis. © 2018 American Institute of Chemical Engineers Environ Prog, 38: 410–416, 2019 [ABSTRACT FROM AUTHOR]

Background The aim of this study is to test different supports on which to deposit Au nanoparticles and to determine the most suitable for Orange II (OII) dye degradation by a photo‐assisted wet peroxidation (PWPO) process. The catalysts used (Au‐Fe2O3, Au‐TiO2, Au‐ZnO and Au‐Al2O3) were prepared by the deposition–precipitation method; a reference catalyst from the World Gold Council, hereafter denoted as Au‐Fe2O3*, was also used for comparison. The catalysts were characterized in terms of surface area (SBET), gold nanoparticles size, Au loading and Au oxidation state using several techniques (namely, nitrogen adsorption at −196°C, X‐ray photoelectron spectroscopy – XPS, and high resolution transmission electron microscopy – HR‐TEM). Several runs were carried out for each material, to evaluate its efficiency in OII dye degradation by the PWPO process. Results: All catalysts reached OII dye removals of >96% and considerable total organic carbon (TOC) degradation – between 58.4% and 80.5%. The materials had negligible Au leaching, showing very good stability. For the catalyst with best performance (Au/Al2O3), a parametric study was carried out to assess the effect of different variables on dye and TOC removals. Under the best conditions, excellent efficiency of the advanced oxidation process was obtained. A simulated industrial acrylic dyeing effluent was also treated by PWPO and very good performance was reached, with removals up to 100%, 72.4% and 70.0% for color, TOC and COD, respectively, with only 2 h of reaction. Moreover, there was an improvement in biodegradability and a non‐toxic effluent was generated. Conclusions: PWPO using nano‐sized gold‐based catalysts proved to be a promising technique for the degradation of pollutants in water. The used gold supports have an important role in the efficiency of the process. The best catalyst was obtained using large surface area Al2O3 as support, although no leaching of gold was found for any of the catalysts. The mineralization degree improved under radiation due the formation of hydroxyl radicals, being reached total dye removal and a decrease of the TOC values greater than 90%. © 2018 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Abstract: The first sensitive fluorescence .OH probe (1) that is capable of monitoring the generation of trace .OH in iron autoxidation is presented. The probe 1 was designed by utilizing both the unique aromatic hydroxylation and the electrophilicity of .OH, and prepared by incorporating a strong electron‐donating methoxy group into a cyanine fluorochrome to enhance the trapping ability for .OH. Reaction of 1 with .OH leads to a larger π‐conjugation formation and near‐infrared fluorescence off–on response. The capability of probe 1 has been demonstrated by imaging .OH generated in living cells under iron autoxidation as well as various stimuli, which reveals that the basal level of .OH in RAW 264.7 cells is lower than that in HeLa cells. The superior analytical performance of probe 1 makes it useful for detecting trace .OH in some critical physiological and pathological processes associated with iron autoxidation. [ABSTRACT FROM AUTHOR]

Abstract: The first sensitive fluorescence .OH probe (1) that is capable of monitoring the generation of trace .OH in iron autoxidation is presented. The probe 1 was designed by utilizing both the unique aromatic hydroxylation and the electrophilicity of .OH, and prepared by incorporating a strong electron‐donating methoxy group into a cyanine fluorochrome to enhance the trapping ability for .OH. Reaction of 1 with .OH leads to a larger π‐conjugation formation and near‐infrared fluorescence off–on response. The capability of probe 1 has been demonstrated by imaging .OH generated in living cells under iron autoxidation as well as various stimuli, which reveals that the basal level of .OH in RAW 264.7 cells is lower than that in HeLa cells. The superior analytical performance of probe 1 makes it useful for detecting trace .OH in some critical physiological and pathological processes associated with iron autoxidation. [ABSTRACT FROM AUTHOR]

Abstract: Because 100 % quantum efficiency for the photosynthetic production of H2 from H2O under visible illumination has been achieved recently, the oxidation of H2O to O2 remains the bottleneck to the overall water‐splitting reaction. Oxidation of CH4 to CH3OH might be combined with water reduction instead, so that H2 and CH3OH chemical fuels can be simultaneously produced through a one‐step process under solar illumination. This combination would be a promising approach towards a more sustainable future of chemistry, in which developing different strategies for artificial photosynthesis is of paramount importance. By using free and adsorbed HO. radicals on the semiconductor surface, CH4 can be activated to H3C. radicals and converted into CH3OH, respectively, with great selectivity up to 100 %. The present lack of efficient photosynthetic systems for the formation of H2 and CH3OH from abundant H2O and CH4 motivates future research for basic science and industrial applications. [ABSTRACT FROM AUTHOR]

Cu-embedded mesoporous alumina, as a Fenton-like catalyst prepared via a sol-gel method, showed excellent activity and durability for the degradation of refectory compounds. The origin of active sites for the generation of hydroxyl radicals (•OH) were thoroughly studied using multitechniques. Cu, as the only active element, could be penetrated into the bulk of alumina and some Cu atoms were embedded into the framework. The dynamic structure of surface Cu species (the variety of Cu+/Cu2+ ratio) during the reaction were determined as well. Furthermore, the structure plasticity of catalyst has proved by optimizing preparation and reaction conditions. A 98.53% degradation of RhB was recorded within 30 min, following a pseudo-first-order reaction rate expression. Electron spin resonance spectra and •OH scavenging experiments have confirmed that •OH is the main reactive oxidant for the elimination of RhB. By the surface-enhanced Raman spectroscopy and gas chromatography-mass spectrometer results, plausible pathways of RhB degradation were elaborated. © 2017 American Institute of Chemical Engineers AIChE J, 64: 538-549, 2018 [ABSTRACT FROM AUTHOR]