Peroxide Ions Research Articles

A Mitochondrial-Targeting Near-Infrared Fluorescent Probe for Revealing the Effects of Hydrogen Peroxide And Heavy Metal Ions on Viscosity.

As an important cell organelle, the mitochondrion has special viscosities, while abnormal mitochondrial viscosity is closely related to many diseases. Hydrogen peroxide (H2O2) is an active molecule related to the cell microenvironment, and its influence on mitochondrial viscosity is still not clear, so further investigation is needed. In addition, since excessive accumulation of heavy metal ions would lead to cells' dysfunction, the study of effect of excessive heavy metal ions on mitochondrial viscosity has not been reported. Herein, we designed and synthesized a mitochondrial-targeting near-infrared fluorescent probe (Mito-NV) for real-time in situ imaging and analysis of mitochondrial viscosity. Furthermore, the probe revealed that H2O2 can raise mitochondrial viscosity, while heavy metal ions reduce the viscosity. This work is of great significance for understanding the execution of mitochondrial functions and the occurrence and development of related diseases.

COD Reduction in Petrochemical Wastewater Using the Solar Photo-Fenton Process

Water has been recognized as the most fundamental factor in organisms' lives and the most widely used element in industries, while currently, the world is dealing with water scarcity in many areas. This emphasizes the importance of preventing water contamination as well as returning contaminated water produced by industries to the production and consumption cycle. Yet, the need for environmental protection is a certain principle that is generalized in today's world. This necessity has become more important with the growth of industries and technologies and subsequent contamination. Advanced oxidation technology has been substantially developed in recent decades, becoming increasingly important in the treatment process of industrial wastewaters containing resistant organic materials that cannot be removed through conventional treatment methods to reduce water quality parameters. The present study has examined the chemical oxygen demand (COD) in the synthetic monoethyl amine wastewater prepared by the solar Photo-Fenton process. Principal effective parameters in the advanced oxidation technology, including the processing time, the concentration of hydrogen peroxide ion, the concentration of iron (II) ion, and pH, were investigated by the response surface methodology (RSM) through 30 random experiments using central composite design method (CCD) to optimize reaction conditions. The most sufficient operational conditions were achieved at pH=4, [Fe2+] =2 mM, [H2O2] =20 mM, and t=90 min for the COD removal rate of 77.08%.

Peroxydisulfate activation by photo-generated charges on mesoporous carbon nitride for removal of chlorophenols

Photogenerated charges were found to involve in activation of peroxydisulfate (PDS) on mesoporous carbon nitride (MCN) with Lewis basic sites under visible light irradiation. Photogenerated hole (h+), superoxide radical (O2·−) and singlet oxygen (1O2) were verified as the most important active species for 2,4,6-trichlorophenol (TCP) removal. Lewis basic sites of MCN induced the interface hydrolysis of PDS to produce hydroperoxyl anions (HOO−) and peroxide ions (O22−), which was further reacted with h+ to generate O2·− and 1O2 predominantly. The efficiently separated electron (e−) was responsible for the nucleophilic attack toward the CCl bond of TCP. Moreover, the electrical energy per order (EEO) of vis/MCN/PDS (3.75 × 106 kW h m−3 order−1) was an order of magnitude lower than that of UV/PDS (3.14 × 107 kW h m−3 order−1). This work highlighted the metal-free MCN with Lewis basic sites as a photocatalyst to activate PDS and elucidated a new strategy of PDS activation for chlorophenol pollutants removal.

Ratiometric fluorescence imaging of hypochlorous acid in living cells and zebrafish using a novel phenothiazine-fused HPQ probe

Hypochlorite (ClO−), as a typical weak acidic ROS, is mainly endogenously produced by myeloperoxidase (MPO) catalyzing hydrogen peroxide (H2O2) and chloride ion (Cl−) in leukocytes. Imbalance of hypochlorite concentration will not only cause biomolecular oxidation in organism, but also are correlated with a variety of physiological diseases. In this study, a novel ratiometric fluorescence probe PHPQ for detecting ClO- by incorporating the phenothiazine moiety into the HPQ fluorophore was designed and synthesized. The probe PHPQ was shown to be capable of selectively and sensitively monitoring ClO- in a fine ratiometric manner. It also displayed the merits of large blue-shift (98 nm), rapid response (30 s), excellent sensitivity (15 nM) and significant fluorescence ratiometric variations (253-fold). Moreover, PHPQ was successfully utilized for bioimaging exogenous/endogenous ClO- in living cells (MGC-803 and RAW264.7) and in zebrafish.

Antioxidant and anti-advanced glycation end products formation properties of palmatine

Context: Oxidative stress and formation of advanced glycation end products (AGEs), due to glycation of proteins, lipids and nucleic acids are characteristic in diabetic patients. Palmatine, a protoberberine alkaloid bioactive isolated from Coscinium fenestratum (CF) stem extract, which previously has shown to possess antidiabetic and antioxidant properties and to be able to protect the kidney and liver in a STZ-diabetic induced rat model. Aims: To evaluate the in vitro and in vivo antioxidant and anti-AGE activity of palmatine. Methods: In vitro and in vivo studies were conducted to measure radical scavenging, reducing power, inhibition of lipid peroxidation, carbonyl trapping and metal ion chelation. In vitro antiglycation activity was done using bovine serum albumin-methylglyoxal (BSA-MGO), bovine serum albumin – glucose (BSA-GLU) and glycated hemoglobin. In vivo antioxidant and antiglycation activity were used to evaluate liver and kidney extracted from STZ-induced diabetic rat after treatment with palmatine. Results: The results showed palmatine blocked the formation of AGE as shown by the results of BSA-GLU, BSA-MGO, glycated hemoglobin and inhibited the free radicals generated by DPPH, nitric oxide, hydrogen peroxide, lipid peroxidation, FRAP and metal ion chelating. It was able to stimulate in vivo the activity of catalase, super oxide dismutase and glutathione peroxidase. Conclusions: Palmatine possess antioxidant and antiglycation properties, the mechanism of action seems to be via the blockage of free radical formation, decreasing of reactive carbonyl. Further research is ongoing to determine the effect of palmatine on glyoxalase 1 and aldose reductase pathway and interaction with receptor for AGE.

Diagnostic Value of Myeloperoxidase Index in Bacterial Infections

Infectious diseases remain a serious problem in Indonesia. Myeloperoxidase (MPO) is a substance released by neutrophils, which activates the synthesis of hypochlorous acid (HOCL) from hydrogen peroxide (H2O2) and chloride ion (Cl-). Hypochlorous acid plays a vital role in the body's defense against infection. Myeloperoxidase Index (MPXI) is a parameter in the hematology analyzer Advia 2120i based on the principle of flow cytometry. This study aimed to determine the diagnostic value of MPXI in patients with bacterial infections. The study was a cross-sectional observational analysis. The samples consisted of a group of patients with bacterial infection and a group of healthy subjects. The specimens used in this study were whole blood + anticoagulant (EDTA) in a purple tube with a volume of 3 mL to determine the MPXI value in both groups using ADVIA 2120i hematology analyzer. The study subjects consisted of a group of patients with bacterial infections (69 patients) and a group of healthy subjects (33 people). Analysis of the MPXI ROC curve with a cut-off ≥ -5.8 and < -5.8, showed AUC of 0.323 (CI=95%, p=0.004), sensitivity of 34.8%, specificity of 39.4%, Positive Predictive Value (PPV) of 54.5%, and Negative Predictive Value (NPV) of 22.4%. Due to its low diagnostic value, the MPXI value was not recommended to be used as a diagnostic instrument for bacterial infections. Also, further research was highly needed.

Efficient oxygen reduction reaction by a highly porous, nitrogen-doped carbon sphere electrocatalyst through space confinement effect in nanopores

A highly porous nitrogen-doped carbon sphere (NPC) electrocatalyst was prepared through the carbonization of biomass carbon spheres mixed with urea and zinc chloride in N2 atmosphere. The sample carbonized at 1000 °C demonstrates a superior oxygen reduction reaction (ORR) performance over the Pt/C electrocatalyst, while its contents of pyridinic nitrogen and graphitic nitrogen are the lowest among samples synthesized at the same or lower carbonization temperatures. This unusual result is explained by a space confinement effect from the microporous and mesoporous structures in the microflakes, which induces the further reduction of peroxide ions or other oxygen species produced in the first step reduction to water to have the preferred overall four electron reduction ORR process. This work demonstrates that in addition to the amount or species of its active sites, the space confinement can be a new approach to enhance the ORR performance of precious-metal-free, nitrogen-doped carbon electrocatalysts.

Update on the Roles of Polyamines in Fleshy Fruit Ripening, Senescence, and Quality.

Ripening of fleshy fruits involves complex physiological, biochemical, and molecular processes that coincide with various changes of the fruit, including texture, color, flavor, and aroma. The processes of ripening are controlled by ethylene in climacteric fruits and abscisic acid (ABA) in non-climacteric fruits. Increasing evidence is also uncovering an essential role for polyamines (PAs) in fruit ripening, especially in climacteric fruits. However, until recently breakthroughs have been made in understanding PA roles in the ripening of non-climacteric fruits. In this review, we compare the mechanisms underlying PA biosynthesis, metabolism, and action during ripening in climacteric and non-climacteric fruits at the physiological and molecular levels. The PA putrescine (Put) has a role opposite to that of spermidine/spermine (Spd/Spm) in cellular metabolism. Arginine decarboxylase (ADC) is crucial to Put biosynthesis in both climacteric and non-climacteric fruits. S-adenosylmethionine decarboxylase (SAMDC) catalyzes the conversion of Put to Spd/Spm, which marks a metabolic transition that is concomitant with the onset of fruit ripening, induced by Spd in climacteric fruits and by Spm in non-climacteric fruits. Once PA catabolism is activated by polyamine oxidase (PAO), fruit ripening and senescence are facilitated by the coordination of mechanisms that involve PAs, hydrogen peroxide (H2O2), ABA, ethylene, nitric oxide (NO), and calcium ions (Ca2+). Notably, a signal derived from PAO5-mediated PA metabolism has recently been identified in strawberry, a model system for non-climacteric fruits, providing a deeper understanding of the regulatory roles played by PAs in fleshy fruit ripening.

Management of Microbiological Contamination of the Water Network of a Newly Built Hospital Pavilion.

The good installation, as well as commissioning plan, of a water network is a crucial step in reducing the risk of waterborne diseases. The aim of this study was to monitor the microbiological quality of water from a newly built pavilion before it commenced operation. Overall, 91 water samples were tested for coliforms, Escherichia coli, enterococci, Pseudomonas aeruginosa and Legionella at three different times: T0 (without any water treatment), T1 (after treatment with hydrogen peroxide and silver ions at initial concentration of 20 mg/L and after flushing of water for 20 min/day for seven successive days) and T2 (15 days later). Coliforms were detected in 47.3% of samples at T0, 36.3% at T1 and 4.4% at T2. E. coli was isolated in 4.4% of the samples only at T1, while enterococci appeared in 12.1% of the samples at T1 and in 2.2% at T2. P. aeruginosa was isolated in 50.5% of the samples at T0, 29.7% at T1 and 1.1% at T2. Legionella pneumophila serogroup 8 was isolated in 80.2% of the samples at T0, 36.3% at T1 and 2.2% at T2. Our results confirmed the need for a water safety plan in new hospital pavilions to prevent the risk of waterborne diseases.

Intrinsic catalase-mimicking MOFzyme for sensitive detection of hydrogen peroxide and ferric ions

Lanthanide metal-organic frameworks (Ln-MOFs) exhibit outstanding properties, including high chemical and thermal stability, as well as their promising enzyme-mimic activity (MOFzyme). A new cerium MOFs (Ce-MOF) was synthesized via a solvothermal method using organic linker 4,4′,4″-nitrilotribenzoic acid (H3NTB). The crystallinity of the prepared material was confirmed using X-ray diffraction (XRD). The coordination between Ce and H3NTB was approved using Fourier transforms infrared (FT-IR). The chemical and oxidation state of Ce-MOF was characterized using X-ray photoelectron spectroscopy (XPS). The analysis of XPS data suggested the presence of two oxidation states of cerium, i.e., Ce(III) and Ce(IV). According to the imaging using a scanning electron microscope (SEM) and transmission electron microscope (TEM), Ce-MOF exhibits hexagonal rods’ morphology. Ce-MOF offered thermal stability up to 350 °C. It showed a fluorescence emission signal at wavelength 550 nm with a Stock’s shift of 200 nm. Ce-MOF’s application as a probe for sensing hydrogen peroxide (H2O2) and ferric ions (Fe3+) was reported. Ce-MOF exhibited peroxidase MOFzyme activity. Thus, it offered a turn-on emission upon interaction with different concentrations of H2O2. It detects Fe3+ ions with a limit of detection (LOD) and a linear range of 0.016 µM and 0.016–0.133 µM, respectively. The study also investigated the mechanisms of sensing for H2O2 and Fe3+ ions. The changes in the emission signals were due to the intrinsic catalase activity of Ce-MOF. Ce-MOF offered MOFzyme properties providing a promising feature for biocatalysis and biosensing applications.

Amorphous ultra-wide bandgap ZnOx thin films deposited at cryogenic temperatures

Crystalline wurtzite zinc oxide (w-ZnO) can be used as a wide bandgap semiconductor for light emitting devices and transparent or high temperature electronics. The use of amorphous zinc oxide (a-ZnO) can be an advantage in these applications. In this paper, we report on x-ray amorphous a-ZnOx thin films (∼500 nm) deposited at cryogenic temperatures by reactive magnetron sputtering. The substrates were cooled by a nitrogen flow through the copper substrate holder during the deposition. The films were characterized by x-ray diffraction, Raman, infrared, UV–Vis-near-infrared spectroscopies, and ellipsometry. The a-ZnOx films on glass and Ti substrates were obtained at the substrate holder temperature of approximately −100 °C. New vibration bands at 201, 372, and 473 cm−1 as well as O–H stretch and bend absorption bands in the a-ZnOx films were detected by Fourier transform infrared spectroscopy. Raman spectra showed characteristic ZnO2 peaks at 386 and 858 cm−1 attributed to the peroxide ion O22− stretching and libration modes, respectively. In addition, the films contain neutral and ionized O2 and O2− species. The a-ZnOx films are highly transparent in the visible light range (≈87%) and exhibit a refractive index of 1.68 at 2.25 eV (550 nm). An optical bandgap is 4.65 eV with an additional band edge absorption feature at 3.50 eV. It has been shown that the deposition on actively cooled substrates can be a suitable technique to obtain low temperature phases that cannot be deposited at room temperature.

Eco-friendly synthesis of lignin mediated silver nanoparticles as a selective sensor and their catalytic removal of aromatic toxic nitro compounds.

The development of an eco-friendly and reliable process for the production of nanomaterials is essential to overcome the toxicity and exorbitant cost of conventional methods. As such, a facile and green synthesis method is introduced for the preparation of lignin mediated silver nanoparticles (L-Ag NPs). This is produced by reducing Ag precursors using lignin biopolymers which are formulated by pulsed laser irradiation and an ultrasonication process. Lignin operates as both a reducing and stabilizing agent. The various analytical techniques of ultraviolet-visible spectroscopy, transmission electron microscope and X-ray diffractometer studies were employed to verify the formation of non-aggregated spherical L-Ag NPs with an average size as small as 7-8nm. The selective sensing capability of the synthesized L-Ag NPs was examined for the detection of hydrogen peroxide and mercury ions in an aqueous environment. Furthermore, the superior catalytic performance of L-Ag NPs was demonstrated by the rapid conversion of toxic 4-nitrophenol and nitrobenzene as targeted pollutants to the corresponding amino compounds. A plausible catalytic reduction mechanism for the removal of toxic nitro-organic pollutants over L-Ag NPs is proposed. This research coincides with existing studies and affirms that L-Ag NPs are an effective sensor that be applied as a catalytic material within environmental remediation and also alternative biomedical applications.

Effective photochemical treatment of a municipal solid waste landfill leachate.

This work aimed at studying the photochemical treatment of a landfill leachate using ultraviolet light, hydrogen peroxide, and ferrous or ferric ions, in a batch recycle photoreactor. The effect of inorganic carbon presence, pH, initial H2O2 amount (0–9990 mg L-1) as well as Fe(II) (200–600 ppm) and Fe(III) (300–700 ppm) concentrations on the total carbon removal and color change was studied. Prior to the photochemical treatment, a pretreatment process was applied; inorganic nitrogen and inorganic carbon were removed by means of air stripping and initial pH regulation, respectively. The leachate sent subsequently for photochemical treatment was free of inorganic carbon and contained only organic carbon with concentration 1200±100 mg L-1 at pH 5.1–5.3. The most favorable concentrations of H2O2 and ferric ions for carbon removal were 6660 mg L-1 and 400 ppm, respectively. Adjusting the initial pH value in the range of 2.2–5.3 had a significant effect on the organic carbon removal. The photo-Fenton-like process was more advantageous than the photo-Fenton one for leachate treatment. By applying the most favorable operating conditions, 88.7% removal of total organic carbon, 100% removal of total inorganic carbon, 96.5% removal of total nitrogen, and 98.2% color removal were achieved.

Multifunctional shape-dependent plasmonic nanoprobe by enzymatic etching of single gold triangular nanoplate

Hydrogen peroxide (H2O2), as a signaling molecule, plays a vital role in a wide variety of signaling transduction processes, aging, and diseases. However, the excessive production of H2O2 causes various diseases. Herein, we develop a novel method for H2O2 detection in live cells via dark-field scattering spectroscopy with gold triangular nanoprisms (AuTNPs) as probes. The corners of AuTNPs would be gradually oxidatively etched by the strong coordination of Br• which is generated by enzymatic reactions in the presence of horseradish peroxidase (HRP), bromide ion and trace hydrogen peroxide. Benefitting from the morphological change, the single AuTNP based plasmonic nanoprobe shows notable blueshifts and scattering color changes which could be real-time monitored under the dark-field microscopy. The peak position in the scattering spectra of individual AuTNP blueshifts linearly with the increase of H2O2 concentration, and exhibits high sensitivity to H2O2 in a large range from 2.5 to 100 µM with a low detection limit (LOD) of 0.74 µM. Moreover, the experimental results were supported by the simulated results via the finite-difference time-domain (FDTD) method. The nanoprobes have been further used for intracellular H2O2 detection in live cells. Besides, the etching of AuTNP also provides an alternative method to design novel plasmonic logic chips and write-once plasmonic memories.

Generation Characteristics of Long-Lived Active Species in a Water Falling Film DBD Reactor

Water falling film dielectric barrier discharge (WFFDBD) has been widely studied for water treatment, due to its good performance on production of active species, mass transfer of active species from gas phase into liquid phase, and therefore the degradation of pollutants. However, few studies have focused on the production characteristics of active species of WFFDBD. In this paper, the formation characteristics of hydrogen peroxide, ozone and nitrate ions in a WFFDBD reactor powered by bipolar pulsed generator were studied under different electric discharge time, peak pulse voltage, power–frequency, air flow rate, water circulation flow rate, pH value and conductivity. The results show that the concentrations of hydrogen peroxide, ozone and nitrate ions increased with the peak pulse voltage, power supply frequency and water circulation flow rate, but the inputted air flow rate presented different effect on the production of active species. Moreover, the increase in pH value and conductivity led to a decrease in the concentration of hydrogen peroxide, while nitrate ion increased with the water pH value and conductivity. The p-nitrophenol degradation result indicates that both ozone and hydrogen peroxide contribute to its degradation possibly via their reaction into hydroxyl radical.

A Fluorescence-Based Assay System for the Determination of Haloperoxidase-Activity Using a Two-Dimensional Calibration Ap-proach.

Screening for an interesting biocatalyst and its subsequent kinetic characterization depends on a reliable activity assay. In this work, a fluorometric assay based on the halogenation of 4‐methyl‐7‐diethylamino‐coumarin was established to monitor haloperoxidase‐activity. Since haloperoxidases utilize hydrogen peroxide and halide ions to halogenate a broad range of substrates by releasing hypohalous acids, a direct quantification of haloperoxidase‐activity remains difficult. With the system presented here, 3‐bromo‐4‐methyl‐7‐diethylaminocoumarin is preferentially formed and monitored by fluorescence measurements. As starting material and product share similar spectroscopical properties, a two‐dimensional calibration ap‐proach was utilized to allow for quantification of each compound within a single measurement. To validate the system, the two‐dimensional Michaelis‐Menten kinetics of a vanadium‐dependent chloroperoxidase from Curvularia inaequalis were recorded, yielding the first overall kinetic parameters for this enzyme. With limits of detection and quantification in the low μm range, this assay may provide a reliable alternative system for the quantification of haloperoxidase‐activity.

Synergistic enhancement of loading contents and chemical stability of lycopene distributing both inside and on the oil/water interface.

Loading contents and chemical stability of lycopene were synergistically enhanced after dispersion in genipin-crosslinked-chitosan (CS) stabilized high internal phase emulsions (HIPEs). HIPEs could be prepared with the parameters for the emulsifiers of CS concentration from 0.5 to 5mg/mL, pH value from 5.5 to 7.5, and CS/genipin mass ratio from 2:1 to 20:1. High loading content of lycopene, up to 0.25 wt% was achieved, with emulsifier in the final system only 1mg/mL. As the loading contents were elevated, increasing amount of lycopene distributed in HIPEs in the form of insoluble crystals. Meanwhile, density of oil droplets decreased and the shape changed from polygon to sphere, which is supposed to be related to the interaction between the crystal and the oil-water interface. Stability of lycopene against ultraviolet, temperature, hydrogen peroxide, and iron ions was improved significantly, which could be ascribed to the layer of genipin-crosslinked-CS on oil droplet surface and the crystal status of lycopene. The storage stability of lycopene was improved tremendously after encapsulation by HIPEs. PRACTICAL APPLICATION: Low loading content of lycopene in emulsion systems is not conducive to the evaluation of its biological function in subsequent experiments, as well as their real application in food industry. It is also crucial to improve the stability of lycopene for the practical application in food industry. In this work, the loading content in delivery system and the chemical stability of lycopene are improved through encapsulation with high internal phase emulsions (HIPEs). The significance of these results may have implications in fields spanning from colloidal science to functional foods applications.

Potential Use of Chemically Synthesized Iron-Pyrite Nanoparticles in Enhancing Plant Growth

Trouncing of seed dormancy and retarded plant growth is a major accomplishment in the sustainable production of agricultural crops. Generally, the activation of the Brassinosteroid (BR) pathway leads to an increase in the breaking of dormancy during seed development and germination. Pyrite in the water system contains trace amounts of ferrous, ferric, sulfate, and hydrogen peroxide ions, thereby forming an acidic milieu, which activates the Brassinosteroid (BR) pathway by the signaling action of hydrogen peroxide ions. Chemical synthesis of iron-pyrite nanoparticles, its characterization followed by testing of its efficacy in activation of BR pathway upon seed treatments, its validation through phytochemical analysis, and GC-MS studies are the main focus of this research work. The nanoparticle in the water system was also studied for its effect on Amylase activity in seed upon nanoparticle treatment. An increase in the amylase activity ultimately resulted in enhanced seed germination by breaking dormancy at a faster rate. The metabolic efficiency and possible toxicity of the plants generated from seed treated with nanoparticles were assessed through bio-chemical methods to corroborate the enhanced growth in plants and the harmlessness of the plants for consumption. The entire study was carried out with seeds of Raphanus sativus, as they have the ability to acclimatize in different agro-climatic conditions.

Synthetic periprosthetic synovial fluid development for in vitro cell-tribocorrosion testing using the Taguchi array approach.

Synovial fluid is dynamic in vivo with biological components changing in ratio and size depending on the health of the joint space, making it difficult to model in vitro. Previous efforts to develop synthetic synovial fluid have typically focused on single organic-tribological interactions with implant surfaces, thus ignoring interplay between multiple solution components. Using a Taguchi orthogonal array, we were able to isolate the individual effects of five independent synovial fluid composition variables: ratios of (1) hyaluronic acid to phospholipids (HA:PL) and (2) albumin to globulin (A:G), and concentrations of (3) hydrogen peroxide (H2 O2 ), (4) cobalt (Co2+ ) and (5) chromium (Cr3+ ) ions on macrophage viability and reduced glutathione production, local solution pH and the comprehensive CoCrMo alloy electrochemical response. While no single synovial fluid variable significantly affected the collective response, HA:PL ratio resulted in the largest impact factor (Δ) on 12 of the 13 measured responses with significant effects (p < .05) on the average macrophage survival rate and electrochemical capacitive state of the CoCrMo surface. Cluster analysis separated significant responses from all trials into three groups, corresponding to healthy, mild, or severely inflamed fluids, respectively; with the healthy synovial fluid composition having mid-range HA:PL ratios with no Co2+ ions, and the severely inflamed fluids consisting of low and high HA:PL ratios with H2 O2 and Co2+ ions. By utilizing the Taguchi approach in combination with cluster analysis, we were able to advance our knowledge of complex multivariate synthetic synovial fluids influence on macrophage and electrochemical behavior at the cell-solution-metal interface.

Treatment of landfill leachate membrane filtration concentrate by synergistic effect of electrocatalysis and electro-Fenton

To address the issues caused by the external addition of Fe in the electro-Fenton reaction, activated carbon catalysts loaded with Fe were prepared by an impregnation method with which a novel Fe-activated carbon-titanium mesh composite air cathode (Fe/AC/Ti cathode) was prepared. The preparation conditions were investigated and determined in terms of chemical oxygen demand (COD) removal efficiency of the nanofiltration concentrate of landfill leachate (LLC). An electrochemical system constructed using the Fe/AC/Ti cathode and a dimensional stable anode (DSA) was developed to treat the LLC. The electrochemical reaction conditions were studied by single-factor experiments and orthogonal array analysis. The highest COD removal (97.06 %) was obtained at an applied voltage of 10 V, initial pH of 7, and electrode distance of 1 cm. The optimum conditions were applied voltage of 8 V, initial pH of 3, and electrode distance of 3 cm for 61.24 % total organic carbon removal. BOD5/COD ratios of all tests increased from 0.03 to between 0.23 and 0.51. The effluent after the reaction was either neutral or weakly alkaline. Neither hydrogen peroxide nor Fe ions were added to the reaction system, and almost no Fe precipitation was produced. The system realized the co-treatment of Cl-containing wastewater by anodic electrocatalytic oxidation and cathode electro-Fenton in the same reactor. We also address this common problem in the electro-Fenton reaction utilizing a simple low-cost method with abundant source-material.