Increasing H2O2 Concentration Research Articles

Optimized Preparation of Porous Coal Gangue-Based Geopolymer and Quantitative Analysis of Pore Structure

The purpose of study is to optimize the preparation of porous coal gangue-based geopolymer and quantitatively analyze its pore structure to establish the relationship between pore structure and mechanical properties. Porous coal gangue-based geopolymers were prepared by using coal gangue as the raw material, Na2SiO3 and NaOH as activators, H2O2 as the foaming agent and carboxymethylcellulose sodium (CMC) as the surfactant. Then response surface methodology (RSM) was used to study effects of liquid-to-solid ratio, CMC content, H2O2 content and curing temperature on compressive strength. Finally, pore number, porosity, pore size distribution and pore structure parameters were analyzed by self-developed image analysis algorithm. RSM results demonstrate that H2O2 content has the greatest effect on mechanical strength, followed by liquid-to-solid ratio, curing temperature and CMC content. Quantitative analysis of pore structure indicate that with the increase in H2O2 content, porosity could increase and pore size and pore shape could become more regular, but mechanical properties sharply deteriorate.

Physicochemical properties and gel-forming ability changes of duck myofibrillar protein induced by hydroxyl radical oxidizing systems.

This paper focuses on the changes of physicochemical properties and gel-forming ability of duck myofibrillar proteins (DMPs) induced using hydroxyl radical oxidizing systems. DMPs were firstly extracted and then oxidized at various H2O2 concentrations (0, 4, 8, and 12 mmol/L) using Fenton reagent (Fe3+-Vc-H2O2) to generate hydroxyl radicals, and the effects of hydroxyl radical oxidation on the physicochemical changes and heat-induced gel-forming capacity of DMPs were analyzed. We observed obvious increases in the carbonyl content (p < 0.05) and surface hydrophobicity of DMPs with increasing of H2O2 concentrations (0-12 mmol/L). In contrast, the free thiol content (p < 0.05) and water retention ability of DMPs decreased with increasing H2O2 concentrations (0-12 mmol/L). These physicochemical changes suggested that high concentrations of hydroxyl radicals significantly altered the biochemical structure of DMPs, which was not conducive to the formation of a gel mesh structure. Furthermore, the gel properties were reduced based on the significant decrease in the water holding capacity (p < 0.05) and increased transformation of immobilized water of the heat-induced gel to free water (p < 0.05). With the increase of H2O2 concentrations, secondary structure of proteins analysis results indicated α-helix content decreased significantly (p < 0.05), however, random coil content increased (p < 0.05). And more cross-linked myosin heavy chains were detected at higher H2O2 concentrations groups through immunoblot analysis (p < 0.05). Therefore, as H2O2 concentrations increased, the gel mesh structure became loose and porous, and the storage modulus and loss modulus values also decreased during heating. These results demonstrated that excessive oxidation led to explicit cross-linking of DMPs, which negatively affected the gel-forming ability of DMPs. Hence, when processing duck meat products, the oxidation level of meat gel products should be controlled, or suitable antioxidants should be added.

Degradation of Triphenyl Phosphate in Water by UV-driven Advanced Oxidation Processes

As a type of emerging pollutant of concern, organophosphate esters (OPEs) have posed a moderate risk to the remote Antarctic waters. Triphenyl phosphate (TPHP) is a common type of OPEs in water, which has been proven to have toxic effects, bioaccumulation, and amplification effects and pose a great threat to the environment and human health. Fourier transform infrared spectroscopy (FT-IR) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) were used to investigate the degradation process of TPHP in three advanced oxidation processes (UV-AOPs), including ultraviolet-hydrogen peroxide (UV-H2O2), ultraviolet-titanium dioxide (UV-TiO2), and ultraviolet-persulfate (UV-PS) systems. This was the first instance of using FT-IR for the online observation of the change in infrared characteristic peaks in the degradation process of TPHP, and its degradation reaction kinetics, photodegradation products, and degradation pathways were analyzed. The results showed that TPHP could be effectively degraded under UV-H2O2, UV-TiO2, and UV-PS systems, and the photodegradation half-lives were 74, 150, and 89 min, respectively. The UV-H2O2 system had the best degradation effect on TPHP. Additionally, the degradation reactions of TPHP in three systems conformed to the first-order kinetics. When the concentration of H2O2 was 0-0.097 mol·L-1, the increase in H2O2 concentration promoted the degradation of TPHP, and when the concentration of TiO2 was 0-0.013 mol·L-1, the increase in TiO2 concentration promoted the degradation of TPHP. The photodegradation pathway of TPHP mainly included the P-O-C bond breaking, the C-H bond cleavage of the benzene ring structure and the hydrolysis reaction of TPHP. The UV-H2O2 system was used to degrade OPEs in the environmental water of Chengdu, and it was found that the removal rate of TPHP was 66% when the water samples of the park landscape water were degraded for 60 min.

H2O2 concentration influenced the photoaging mechanism and kinetics of polystyrene microplastic under UV irradiation: Direct and indirect photolysis

Although numerous studies on microplastic aging have been conducted, information on the contribution of direct and indirect photoaging processes is still deficient. This study is designed to make progress in filling the gap. Specifically, the effects of H2O2 concentration and light source on the physicochemical properties of polystyrene (PS) microplastics before and after photoaging treatment were investigated. Also, the impact of H2O2 concentration on the direct and indirect photoaging process was analyzed by using a pseudo-first-order kinetic equation. The results show that UV/H2O2 system can significantly change the PS, and the fragmentation of PS proceeded with the initial-fast and then-slow trend. Direct photolysis dominated at the low H2O2 concentration range or in the early aging stage, while indirect photolysis gradually takes the leading role with the increase of H2O2 concentration or PS aging degree. This study provides valuable insights into the aging and separation of microplastics in natural aquatic environments.

Mycological synthesis of Ruthenium oxide quantum dots and their application in the colorimetric detection of H2O2

Ruthenium oxide nanoparticles (RuO2 NPs) are one of the most prospective materials at the nanoscale and have comprehensive applications in sensors, microelectronics, energy storage, and more. In an urge to develop novel clean, cost-effective, and efficient synthesis procedures scientists are inclining more towards the biosynthesis of nanoparticles. However, in comparison to other metal oxides, there are no reports on the microbial synthesis of nanocrystalline RuO2, to the best of our knowledge. For the first time, we report on the effective fungal-mediated production of fluorescent Ruthenium oxide quantum dots (RuO2 QDs) by the endophytic fungus Fusarium oxysporum, at room temperature which was previously chemically and physically synthesized at elevated temperatures (more than 1000 °C). Different characterization techniques such as UV–visible (UV–Vis) spectroscopy, Photoluminescence (PL), X-ray Diffraction (XRD), Transmission Electron Microscopy (TEM), and Fourier Transformed Infrared Spectroscopy (FTIR) were performed to characterize the RuO2 QDs. We attempted to investigate the colorimetric detection of H2O2 using these mycosynthesized RuO2 QDs at three different ratios. Our results revealed that the RuO2 absorption peak decreases with increasing H2O2 concentration (in the range 10-2M−10−6M) with a limit of detection of 0.39 µM. Further, the proposed assay was also proved to be suitable for the detection of H2O2 spiked-in plasma samples.

Involvement of ethylene in melatonin-modified photosynthetic-N use efficiency and antioxidant activity to improve photosynthesis of salt grown wheat.

The involvement of melatonin in the regulation of salt stress acclimation has been shown in plants in this present work. We found that the GOAL cultivar of wheat (Triticum aestivum L.) was the most salt-tolerant among the investigated cultivars, GOAL, HD-2967, PBW-17, PBW-343, PBW-550, and WH-1105 when screened for tolerance to 100 mM NaCl. The application of 100 μM melatonin maximally reduced oxidative stress and improved photosynthesis in the cv. GOAL. Melatonin supplementation reduced salt stress-induced oxidative stress by upregulating the activity of antioxidant enzymes, such as superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR), and reduced the glutathione (GSH) production. This resulted in increased membrane stability, photosynthetic-N use efficiency and photosynthesis in plants. The application of 50 μM of the ethylene biosynthesis inhibitor aminoethoxyvinylglycine (AVG) in the presence of melatonin and salt stress increased H2 O2 content but reduced GR activity and GSH, photosynthesis, and plant dry mass. This signifies that melatonin-mediated salt stress tolerance was related to ethylene synthesis as it improved antioxidant activity and photosynthesis of plants under salt stress. Thus, the interaction of melatonin and ethylene bears a prominent role in salt stress tolerance in wheat and can be used to develop salt tolerance in other crops.

Production of Cr(VI) from CrxFe1–x(OH)3 precipitates and NOM-Cr(III) colloids upon reaction with H2O2 under oxic conditions

Cr(III)-Fe(III) hydroxides (CrxFe1–x(OH)3 precipitates) and NOM-Cr(III) colloids are common products of Cr(VI) reduction during remediation and natural processes. However, re-oxidation of Cr(III) to Cr(VI) can undermine remediation efforts. Nevertheless, until now, less is known about the oxidation of Cr(III) from naturally occurring Cr(III) (i.e., CrxFe1–x(OH)3 precipitates and NOM-Cr(III) colloids) by H2O2. Here, we examined the oxidation of Cr(III) from Cr0.5Fe0.5(OH)3 and NOM-Cr(III) colloids by H2O2 under oxic conditions. Batch experiments demonstrated that Cr(VI) generation via Cr(III) oxidation from both Cr0.5Fe0.5(OH)3 and NOM-Cr(III) colloids increased with increasing H2O2 concentration. Increasing pH and addition of Fe2+ promoted Cr(III) oxidation, but the promoting effect of pH was more significant on Cr0.5Fe0.5(OH)3, whereas the promoting effect of Fe2+ was significant on NOM-Cr(III) colloids. By evaluating the effects of Fe species on Cr(VI) generation from Cr0.5Fe0.5(OH)3 and NOM-Cr(III) colloids, we proposed that an intermediate reactive Fe species formed during the reaction with H2O2 activated Cr(III) oxidation. X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) analyses collectively supported that the surface structural Fe in CrxFe1–x(OH)3 precipitates might contribute to the formation of reactive Fe species that promoted Cr(III) oxidation. In contrast, the decomposition of complexed NOM from NOM-Cr(III) colloids enabled the formation of Cr(III)-H2O2 complex that is favorable for subsequent Cr(III) oxidation. Results gained from this study provide a complete understanding of the long-term stability of naturally occurring Cr(III) under environmentally relevant conditions.

Preparation of hydrochar bio-based catalyst for fenton process in dye-containing wastewater treatment

The use of synthetic dyes in the textile industry pollutes a huge amount of water. Thus, wastewater discharged from many textile companies to the receiving environment without being treated causes serious environmental and human health problems. The development of new techniques has become imperative. In this study, it was aimed to remove anionic dye (RR180) and cationic dye (BR18) by Fenton-like and adsorption process with hydrochars obtained from laurel leaves and watermelon peels. In the comparison of the adsorption and Fenton-like processes used in the dye removal of the produced bio-based materials, the Fenton-like process was selected in order to enhance the highest removal efficiency. The effects of various operating factors such as solution pH, amount of catalysts, hydrogen peroxide (H2O2) concentration, and initial dye concentration were evaluated on both dyes removal. The experimental results demonstrated that 99.8% RR180 dye and 98.8% BR18 dye removal efficiency were observed for an initial dye concentration of 100 mg/L with an adsorbent concentration of 1 g/L, H2O2 concentration of 15 μL/L, and optimum pH at the end of 60 min of reaction time. It was observed that an increase in initial dye concentration caused to decrease the dye removal efficiency. The optimum pH for the highest RR180 and BR18 dye removal was 4 and 6, respectively. It was observed that the increase in H2O2 concentration in the solution also decreased the dye removal efficiency. It turned out that catalysts obtained from hydrochars are an effective process for the high removal performance of cationic and anionic dyes.

Oncocyte Membrane-Camouflaged Multi-Stimuli-Responsive Nanohybrids for Synergistic Amplification of Tumor Oxidative Stresses and Photothermal Enhanced Cancer Therapy

The combination of various therapeutic modalities has received considerable attention for improving antitumor performance. Herein, an innovative nanohybrid, namely CaO2@FePt-DOX@PDA@CM (CFDPM), was developed for synergistic chemotherapy/chemodynamic therapy/Ca2+ overloading-mediated amplification of tumor oxidative stress and photothermal enhanced cancer therapy. Camouflage of the 4T1 cell membrane enabled CFDPM to escape the immune surveillance and accumulate in the tumor tissue. Ca2+, released from CaO2, could lead to mitochondrial dysfunction and facilitate the production of reactive oxygen species to amplify intracellular oxidative stress. Meanwhile, the increase of H2O2 concentration could enhance the efficiency of the chemodynamic therapy (CDT). Moreover, the hypoxic condition could be alleviated remarkably, which is attributed to the sufficient O2 supply by CaO2, resulting in the suppression of drug resistance and promotion of the chemotherapeutic effect. The nanohybrids involving Ca2+ overloading/CDT/chemotherapy could synergistically amplify the tumor oxidative stresses and remarkably aggravate the death of cancer cells. Significantly, the excellent photothermal conversion performance of CFDPM could further promote the tumoricidal effect. The in vitro and in vivo studies revealed that CFDPM could effectively advance the therapeutic efficiency via the cooperation of various therapeutic modalities to optimize their individual virtue, which would open a valuable avenue for effective cancer treatment.

A thioredoxin peroxidase protects Pieris rapae from oxidative stress induced by chlorantraniliprole exposure.

Chlorantraniliprole (CAP) is an insecticide widely used to control the small white butterfly (SWB), Pieris rapae. Exposure to CAP can cause oxidative injury in SWB; however, it is unclear if antioxidant enzymes are involved in the defense process. In this study, a thioredoxin peroxidase (PrTPX1) gene was identified from SWB by using a homology search method. The gene encoded a 195 amino-acid PrTPX1 protein. Sequence characteristics and phylogenetic analysis indicated that PrTPX1 was a typical "2-Cys" TPX, and the PrTPX1 gene consisted of four exons and three introns. Reverse transcription-quantitative polymerase chain reaction analysis indicated that the messenger RNA levels of PrTPX1 were highest in third-, fourth- and fifth-instar larval stages and in the larval midgut. Treatment with sublethal doses (LD20 and LD50 ) of CAP for 6, 12, 18, and 24 h resulted in increased H2 O2 concentration in SWB larvae, indicating insecticide-induced oxidative stress. The transcriptional levels of PrTPX1 were significantly enhanced in larvae exposed to CAP. Recombinant PrTPX1 protein was expressed in Escherichia coli. Enzymatic assay revealed that the protein displayed antioxidant activity and was able to protect against oxidative challenge. These results indicated that PrTPX1 plays an important role in oxidative stress responses and may contribute to the CAP tolerance in SWB.

Propiconazole degradation and its toxicity removal during UV/H2O2 and UV photolysis processes.

Propiconazole (PRO) is a triazole fungicide that is frequently detected in the water. In this study, we investigated the kinetics and degradation mechanism of PRO during the UV photolysis and UV/H2O2 processes. PRO was removed by the pseudo-first-order kinetics in both processes. The removal of PRO was enhanced by increasing H2O2 concentration in the UV/H2O2 process. The highest removal under neutral conditions, and lower removal of PRO were observed in acidic and alkaline pHs in the UV/H2O2 process. The presence of natural water ingredients such as Cl-, NO3-, humic acid acted as radical scavengers, but HCO3- ion acted as both radical promoter and scavenger in the UV/H2O2 process. The transformation products (TPs) of PRO during both processes were identified using LC-QTOF/MS. Four TPs ([M+H]+=238, 256, 306, and 324) were identified during UV photolysis, and six TPs ([M+H]+=238, 256, 306, 324, 356, and 358) were identified in the UV/H2O2 process. Among the identified TPs, TP with [M+H]+ values of 356 and 358 were newly identified in the UV/H2O2 process. In addition, ionic byproducts, such as Cl-, NO3-, formate (HCOO-), and acetate (CH3COO-), were newly identified, indicating that significant mineralization was achieved in the UV/H2O2 process. Based on the identified TPs and ionic byproducts, the degradation mechanisms of PRO during two processes were proposed. The major reactions in both processes were ring cleavage and cyclization, and hydroxylation by OH radicals. The Microtox test with Vibrio fischeri showed that, while the toxicity of the reaction solution increased first, then gradually decreased during UV photolysis, the UV/H2O2 process initially increased toxicity at 10min due to the production of TPs, but toxicity was completely removed as the reaction progressed. The results obtained in this study imply that the UV/H2O2 process is an effective treatment for eliminating PRO, its TPs, and the resulting toxicity in water.

In-situ generation of H2O2 by zero valent iron to control depolymerization of lignocellulose in composting niche.

Lignocellulosic degradation is a bottleneck of bioconversion during the composting process. In-situ generation of H2O2 in the composting system was an ideal method for efficiently promoting lignocellulase degradation, and zero valent iron (ZVI) was concerned because it can generate H2O2 by reducing dissolved oxygen. This study focused on the effects of ZVI treatment on lignocellulose degradation, microbial communities, and carbohydrate-active enzymes (CAZymes) genes during composting. Its results indicated that ZVI increased H2O2 content during composting, accompanied by the formation of •OH. The degradation rates of lignin, cellulose and hemicellulose in ZVI group (20.77%, 30.35% and 44.7%) were significantly higher than in CK group (17.01%, 26.12% and 38.5%). Metagenomic analysis showed that ZVI induced microbial growth that favored lignocellulose degradation, which increased the abundance of Actinobacteria and Firmicutes but reduced Proteobacteria. At the genus level, the abundance of Thermomonospora, Streptomyces, and Bacillus significantly increased. In addition, glycoside hydrolases and auxiliary activities were important CAZymes families of lignocellulose degradation, and their abundance was higher in the ZVI group. Redundancy analysis showed that the increased H2O2 and •OH content was a critical factor in improving lignocellulose degradation. Overall, H2O2 as a co-substrate enhanced the enzymatic efficiency, •OH unspecifically attacked lignocellulose, and the increase in functional microbial abundance was the main reason for promoting lignocellulose degradation in composting.

Investigation of H2O2/UV advanced oxidation process on the removal rate of coliforms from the industrial effluent: A pilot-scale study

Wastewater recycling and reuse is very important, specially in countries with water shortage problem. Disinfection is very crucial step of wastewater treatment, particulary from the reuse and environmental protection point of view. In this research, the efficiency of the advanced oxidation process using UV and H2O2 combination was investigated on fecal coliform (FC) inactivation from a real industrial effluent; furthermore, the optimal condition for disinfection of the effluent using various parameters such as pH, H2O2 concentration, and contact time was determined. Based on the acquired outcomes, by pH decline from 11 to 7 and 3 inactivation rate increased (6.7% and 20.9%, sequentially), indicating the efficacy of acidic condition on the process. Increasing H2O2 concentration from 5 mg/L to 15 mg/L, 25 mg/L, and 35 mg/L, was led to increase FC inactivation by 16.6%, 29.75%, and 36.33%, respectively. Considering contcat time impact on the process performance, our findings revealed that the best efficiency obtained after 40 (s) contact time. It can be concluded that the combined UV/H2O2 is more potent than single UV and H2O2 process, making it possible to reach irrigation standards.

The removal of NO from flue gas by NaOH-catalyzed H2O2 system: Mechanism exploration and primary experiment

Currently, most advanced oxidation denitrification technologies require long flue gas residence time to obtain ideal NO removal efficiency. The NaOH-catalyzed H2O2 system proposed in this paper can obtain 98% NO removal efficiency under the condition of flue gas residence time of 3 s. The mechanism of NO removal and H2O2 decomposition to O2 were proposed. It was confirmed with ESR (Electron-spin-resonance), inhibitor experiments and UV-Vis spectrophotometer that the main group in the reaction process was·O2- radicals, which reacted with NO to form ONOO-, and ONOO- would be gradually transformed into NO3- and NO2- in the air. The effect of some primary factors on the NO removal efficiency and the percentage of H2O2 decomposition to O2 were also investigated. The increase of initial pH has a positive effect on NO removal, while the promotion of NO removal by increasing H2O2 concentration and reaction temperature is limited and the increase of NO has a negative effect on NO removal. Initial pH has a dual impact on the percentage of H2O2 decomposition to O2, H2O2 concentration and reaction temperature promote the decomposition of H2O2 to O2, while NO concentration has an inhibiting effect on it.

Simulated microgravity contributed to modification of callogenesis performance and secondary metabolite production in CannabisIndica

In vitro plant culture paves the way for meeting the industrial demand of pharmaceutically valuable secondary metabolites. This study intends to monitor how callus cells of Cannabis indica respond to the simulated microgravity (clinorotation; a Man-made technology). Callus initiation resulted from the culture of the leaf explant in a medium supplemented with kinetin (0.5 mgL−1) and 2, 4-D (2 mgL−1). Calli were treated with microgravity at three exposure times (0, 3, and 5 days). The microgravity treatments increased callus biomass about 2.5-fold. The clinorotation treatments transcriptionally induced the olivetolic acid cyclase (OAC) and olivetol synthase (OLS) genes about 6.2-fold. The tetrahydrocannabinolic acid synthase (THCAS) and cannabidiolic acid synthase (CBDAS) genes displayed a similar upward trend in response to microgravity. The applied treatments also stimulated the expression of the ethylene-responsive element-binding proteins (ERF1B) and WRKY1 transcription factors by an average of 7.6-fold. Moreover, the simulated microgravity triggered epigenetic modification in the DNA methylation profile. The HPLC-based assessment validated the high efficacy of the clinorotation treatments to increase the concentration of cannabinoids, including Cannabigerol (CBG) and Cannabidiol (CBD). However, the clinorotated calli contained a lower concentration of Tetrahydrocannabinol (THC) than the control group. The microgravity treatments increased concentrations of proline (79%), soluble sugars (61.3%), and proteins (21.4%) in calli. The biochemical assessment revealed that the clinorotation treatments slightly increased H2O2 concentration. The upregulation in the activities of peroxidase, catalase, and phenylalanine ammonia-lyase enzymes resulted from the microgravity treatments. Both HPLC and molecular assessments validated the significant efficacy of microgravity to enhance the production of cannabinoids.

The role and mechanisms of the two-component system EnvZ/OmpR on the intracellular survival of Aeromonas hydrophila.

Aeromonas hydrophila infections are common in aquaculture. Our previous studies found that the A.hydrophila B11 strain can survive in fish macrophages for at least 24 h and the two-component system EnvZ/OmpR may be involved in intracellular survival. To reveal the role and mechanism of the two-component system EnvZ/OmpR in intracellular survival of A.hydrophila, the genes of envZ/ompR were silenced by shRNAi. The results showed that the survival rates of the envZ-RNAi and ompR-RNAi strains were only 2.05% and 3.75%, respectively, which were decreased by 91% and 83.6% compared with that of the wild-type strain. The escape ability of envZ-RNAi and ompR-RNAi was also decreased by 51.4% and 19.7%, respectively. The comparative transcriptome analysis revealed that the functional genes directly related to bacterial intracellular survival mainly included the genes related to anti-stress capacity, and the genes related to Zn2+ and Mg2+ transport. Further research confirmed that two-component system EnvZ/OmpR can regulate the expression of the important molecular chaperones, such as groEL, htpG, dnaK, clpB and grpE. The expression of these molecular chaperones in wild-type strain was up-regulated with the increase in H2 O2 concentrations, while the expression of these molecular chaperones in silent strains did not change significantly. Cells that phagocytosed wild-type strain had higher ROS content than cells that phagocytosed silent strains. Two-component system EnvZ/OmpR could also regulate zinc transporter (znuA, znuB, znuC) and zinc efflux protein (zntA) to maintain zinc homeostasis in cells, thus affecting the ability of bacteria to survive in phagocytes. Moreover, two-component system EnvZ/OmpR could affect the growth and intracellular survival of A.hydrophila by regulating the expression of MgtA, MgtC and MgtE and participating in bacterial Mg2+ homeostasis in fish macrophages.

Statistical optimization of process conditions for pyrvinium pamoate elimination using UV/zeolite‐based nanostructures/H 2 O 2

Statistical optimization of process conditions for pyrvinium pamoate elimination using UV/zeolite‐based nanostructures/H ₂ O ₂

Performance and degradation pathways of bromuconazole by gamma radiation in aqueous solutions

Gamma irradiation has received increasing attention due to its high potential in the degradation of recalcitrant pollutants. Thus, in the present study, gamma irradiation was used for the degradation of bromuconazole with the presence of hydrogen peroxide (H2O2) as a source of •OH and humic acid as natural organic matter. The effects of initial concentration, irradiation doses and pH were examined. A kinetic study was performed, and the by-products were identified by HPLC-QTOF-MS/MS. Results showed that the degradation process of bromuconazole was pseudo-first-order and 99.9% of bromuconazole was decomposed under an absorbed dose of 1 kGy. The percentage of removal increased with doses and the degradation process was accelerated under neutral conditions. The addition of H2O2 showed a synergistic effect on the decomposition of bromuconazole and the degradation efficiency increased with the increase of H2O2 concentration. Humic acid indicated a negative influence on the degradation efficiency, which decreased from 99.6% to 70.365% at a dose of 0.8 kGy when the humic acid concentration was 20 mg/L. Six degradation products were identified and the kinetic rates of three intermediate compounds were calculated using a Himmelblau-Jones-Bischoff numerical analysis technique. A study conducted by 1H NMR indicated a complete mineralization at 1.2 kGy.

Ready-to-use optical H2O2 sensor based on stimuli-responsive polyacrylic film and nanofibers containing spiropyran

Nowadays, design of conventional and efficient optical H2O2 sensors would be of great importance due to their lower cost and ease of follow-up, compared to the other widely used techniques such as electrochemical or chromatographic methods. Here, stimuli-responsive sensors containing photochromic (R/S)-2-(3′,3′-dimethyl-6-nitro-3′H-spiro[chromene-2,2′-indole]-1′-yl) ethanol (SPOH) and acrylic terpolymer film or nanofibers were prepared for H2O2 detection through a reaction-induced and concentration-dependent process. The polymer phase acts as an efficient substrate for exploitation of such sensors in aqueous media. Poly(methyl methacrylate-butyl acrylate-hydroxyethyl methacrylate) (MBH) was prepared via miniemulsion polymerization and its chemical structure was characterized by FTIR and 1H NMR spectroscopies. Then, it was doped with SPOH and the corresponding film (MBH/SPOH@F) and nanofibers (MBH/SPOH@NF) were fabricated via spin-coating and electrospinning techniques, respectively, and their morphologies were investigated by SEM. Colorimetric analyses were employed to evaluate performance of the obtained samples toward H2O2 after sensitization by UV irradiation. Both samples demonstrated visual color changes together with decrement in maximum absorption wavelengths with the increase in H2O2 concentration. Limit of detection (LOD) for MBH/SPOH@F and MBH/SPOH@NF were calculated to be 11 and 2.3 mg/dL, respectively. Moreover, MBH/SPOH@NF showed faster response (50 min) with respect to MBH/SPOH@F (60 min). Enhanced sensitivity of MBH/SPOH@NF comes from higher specific surface area and porosity of the nanofibers compared to the corresponding film. This led to more accessibility of H2O2 to SPOH molecules in the detection process. Finally, practical application of the ready-to-used and solid sensor was validated with the recovery of 94–97% in water resources.

Overexpression of OHPs in Neopyropia yezoensis (Rhodophyta) reveals their possible physiological roles

The red macroalga Neopyropia yezoensis is a model organism, and an economically important seaweed widely cultured in eastern Asian countries. Transgenic research on N. yezoensis is difficult and limited to reporter genes and selection markers due to the specificities of this species. In this study, plasmids were constructed to overexpress six one helix protein (OHP) coding genes in N. yezoensis, and four transgenic lines with high expression levels of the target genes were obtained. The photosynthetic parameters were determined and it was found that the overexpression of OHPs altered electron transport in photosystem I and photosystem II, which was indicated by the increased 1-qL values and decreased P700+ reduction rates. The results also showed that the non-photochemical quenching (NPQ) kinetics in N. yezoensis could not be stimulated by high light (HL) treatment. Two of the four transgenic lines showed stimulated NPQ, and they did not exhibit an obvious increased ability to resist to HL, which was shown by the decreased Fv/Fm values. The increased H2O2 content and decreased peroxidase (POD) activity were considered the possible results of the overexpressed OHPs, and they were responsible for the enhanced NPQ and HL sensitivity in those two transgenic lines.