Reduction Of Permanganate Research Articles

Operando Spectroelectrochemical Imaging of Concentration Fields and Tafel Kinetics in Microfluidic Electrochemical Devices.

With the development of microtechnologies for energy conversion and storage, mass transfer and micromolar concentration variations need to be measured at the microscale. These advances need to be accompanied by novel imaging techniques with the capability of achieving high spatial resolution while detecting very small signal variations (less than 0.1%). Thus, in this study, a new microscopy technique is proposed based on a combination of electrochemical impedance spectroscopy (EIS) and visible imaging spectroscopy to measure the concentration fields at the micromolar scale in operando microfluidic fuel cells (MFCs). This technique exploits EIS modulation and Fourier analysis to reduce the noise during concentration field imaging. A mass transfer model in the periodic regime is derived to validate the measurements and to estimate the Tafel kinetics and mass diffusivities during potassium permanganate reduction from only one potential measurement. The proposed imaging method and mathematical framework presented in this study can be used to study binary electrochemical reactions without gas production.

DNA Probing of Peroxidase‐Mimetic Activities of Selected Manganese‐Based Nanozymes and Measurement of Antioxidant Activity for DNA Protection

AbstractThree different Mn‐based peroxidase‐mimetic nanoparticles (NPs) were synthesized as nanozymes: (i) manganese (II)‐ferrite (MnFe2O4) fabricated by co‐precipitating MnCl2.4H2O and FeCl3.6H2O; (ii) MnO2 synthesized from precipitation of MnSO4 in basic medium; (iii) manganese oxide obtained by reducing KMnO4 with tris(2‐hydroxyethyl) amine, all characterized using STEM, EDXS, FTIR and XPS techniques. These NPs acted as peroxidases, revealed by using a DNA probe, on which the damage generated by peroxidase mimetic NPs was monitored spectrophotometrically by CUPRAC and 3,3′,5,5′‐tetramethylbenzidine (TMB) methods. Results were confirmed by RP‐HPLC and voltammetry, the latter involving an AuNPs‐modified glassy carbon electrode (GCE), multi‐walled carbon nanotubes (MWCNT) and Nafion combination. Colorimetric assay with CUPRAC rather than TMB better agreed with chromatographic/voltammetric findings in detecting both peroxidase activity and DNA hazard. Mn(III)‐containing manganese oxide from permanganate reduction had stronger peroxidase activity. The proposed method demonstrated protective effects of antioxidants (morin, catechin and quercetin) against oxidative DNA damage for the first time.

Fluorescent Mn3O4 quantum dot as catechol oxidase nanozyme: A robust nano-platform for sensitive dopamine detection

The development of multifunctional semi-conductor nano-enzymes has attained significant interest recently, due to their ease in fabrication, cost-effectiveness, and wide range of applications. In this work, we report the synthesis of ammine-functionalized Mn3O4 quantum dots (Mn3O4 QDs) with excellent luminescence properties. These QDs have been developed via the reduction of permanganate using L-cysteine through a simple, facile one-step bottom-up approach. The steady-state enzyme kinetic studies revealed the superior Catechol-Oxidase mimic activity of the Mn3O4 QDs with a Michaelis-Menten constant (Km) of 133.19 µM, and maximum reaction velocity (Vmax) of 69.40 µMs−1. Due to this superior enzymatic activity, dopamine (DA) gets easily oxidized into DA-quinone and eventually polymerized to form polydopamine. Schiff base/Michael addition reaction between nucleophilic ammine on the surface of QDs and the aromatic chain makes the probe and analyte come closer and leads to the formation of a charge transfer complex, resulting in fluorescence quenching of QDs. This fluorescence quenching has been quantified to develop a turn-off sensor for DA. The sensing characteristics are highly selective and sensitive towards DA with a detection limit of 18 nM. The synthesised Mn3O4 QDs with superior enzyme-mimicking properties have tremendous potential as fluorescent probes in imaging and health care applications.

Kinetics of permanganate–sulfuric acid redox reaction with cetyltrimethylammonium bromide

AbstractThe permanganate–H2SO4 redox reaction, useful in oxidative treatments under aqueous conditions, was studied spectrophotometrically in the absence and presence of cetyltrimethylammonium bromide (CTAB). The decolorization reactions were influenced by the [MnO4−], [H2SO4], and temperature. Permanganate reduction follows first‐, and complex–order kinetics with permanganate, and H2SO4 concentrations, respectively. The reduction of permanganate (Mn(VII)) proceeds through a complex formation between MnO4− and H2SO4. The characteristic absorption peaks for MnO42− (λmax = 439 and 606 nm), MnO43− (λmax = 667 nm), and MnO2 (λmax = 400–418 nm) were not appeared during the redox reaction. The KMnO4 degradation efficiency remains unaffected with sodium pyrophosphate and sodium fluoride. The results of this study demonstrated the formation of Mn(II) as the stable product in acidic reaction media. The degradation efficiency increases drastically from 15 to 100% with 2.0 × 10−4 to 16.0 × 10−4 mol/L CTAB concentration under sub‐, and post‐micellar reaction conditions, respectively. The thermodynamic parameters (activation energy = 98.8 and 43.2 kJ/mol), activation of enthalpy (96.3, and 39.0 kJ/mol), activation of entropy (16.2 and −149.5 J/K/mol), free energy of activation (93.1 and 83.5 kJ/mol) were calculated without and with CTAB, respectively. Hence, CTAB can be exploited for its multifunctional applications, and specifically for the catalytic role in the permanganate‐assisted redox reactions in future.

Potential in-vitro antioxidant and anti-inflammatory activity of Martynia annua extract mediated Phytosynthesis of MnO2 nanoparticles

The present research work describes the phyto-synthesis of Manganese dioxide nanoparticles (MnO2NPs) from the reduction of potassium permanganate using Martynia annua (M.annua) plant extract. From the literature review, we clearly understood the M.annua plant has anti-inflammatory activity. Manganese dioxides are important materials due to their wide range of applications. Their increased surface area gives them distinct capabilities, as it increases their mechanical, magnetic, optical, and catalytic qualities, allowing them to be used in more pharmaceutical applications. A detailed review of literature highlighting the issues related to this present work and its knowledge gap that none of the inflammatory activities had been done by MnO2 NPs synthesized from M.annua plant extract. So we selected this study. The product MnO2 NPs showed the wavelength centre at 370 nm and was monitored by UV–Vis spectra. The wave number around 600 cm−1 has to the occurrence of O–Mn–O bonds of pure MnO2 confirmed by FTIR spectroscopy. Transmission electron microscopy images showed the morphology of MnO2 NPs as spherical-shaped particles with average sizes at 7.5 nm. The selected area electron diffraction analysis exhibits the crystalline nature of MnO2 NPs. The obtained MnO2 NPs showed potential antioxidant and anti-inflammatory activity was compared to the plant extract. The synthesized MnO2 NPs have a large number of potential applications in the field of pharmaceutical industries. In the future, we isolate the phytocompounds present in the M.annua plant extract and conduct a study against corona virus. MnO2 produces manganese (III) oxide and oxygen, which increases fire hazard. But further research is required to understand their environmental behaviour and safety.

Silica Grafted Imprinted Mesoporous Polymer for the Development of SPE Coupled FAAS Method of Nickel Determination, Removal, and Spent Polymer for Reduction of Permanganate: Multivariate Optimization

AbstractA novel silica fabricated allyloxy ethanol based imprinted polymer is synthesised with surface area of 333 m2 g−1 and average pore size of 6.5 nm by an environment friendly one pot surface imprinting process. It was employed for the selective solid‐phase extraction (SPE) of trace Ni(II) in real samples prior to FAAS determination. The factor settings produced via central composite design in response surface methodology (RSM) (pH: 3.6; initial concentration; 800 mg L−1 and time; 15 minute) provide adsorption capacity of 176 mg g−1. Artificial neural network model employed on the RSM data, provided better predictability. Sips isotherm model and BSf kinetic model describes best the sorption phenomena of the homogenous binding terrain. The developed SPE‐coupled FAAS method demonstrate a detection limit of 1.62 μg L−1, quantification limit of 4.17 μg L−1, and Linear dynamic range of 20–8000 μg L−1. It was successfully applied to determine nickel in food (Spinach, Radish, Green tea infusion, Black tea infusion, Coffee, Soya milk, Chocolate Soya milk, Tobacco) and wastewater samples (>99 % removal). For five replicate determinations, the method‘s relative standard deviation was 2.3 %. The method was validated by analysing two certified reference materials, and the outcomes were well‐congruent with standard values. For the synthesised polymer Ni(II) exhibits higher distribution ratio than other competing ions (Cu(II), Pb(II), Cd(II), and Zn(II)) with the imprinting factor; β values of 5.73, 4.98, 6.80, and 5.04 respectively. The reusability experiments revealed that APS@Ni‐IIP retains a strong adsorption efficacy even after 15 cycles and after its exhaustion it was employed as catalyst for reducing permanganate ions, further reducing pollution. The rigid structure of mesoporous silica contributes to its acid resilience and reusability, which can lead to a relative increase in polymer performance in absorption rate and selectivity. Apart from the novelty in the synthesis, thorough examination of the method and material selectivity (in binary, ternary and multielement system), multi fold applications of determination, removal of Ni(II) and reduction of permanganate ions, makes APS@Ni‐IIP a promising candidate for environmental remediation.

Green synthesis of Plectranthus amboinicus leaf extract incorporated fine-tuned manganese dioxide nanoparticles: Antimicrobial and antioxidant activity

Plectranthus amboinicus Manganese dioxide (PA-MnO2) nanoparticles were synthesized by the reduction of potassium permanganate (KMnO4) using Plectranthus amboinicus (P. amboinicus) leaf extract at room temperature. A dark brown colour appeared after the addition of leaf extract to the solution of KMnO4. PA-MnO2 nanoparticles showed absorbance maximum at 324 nm. Scanning Electron Microscopy (SEM) study of particle size and morphology revealed that PA-MnO2 nanoparticles have spherical structures in shape. The electron dispersive X-ray spectroscopy confirmed the presence of Mn and O in the sample. Fourier Transforms infrared spectra of PA-MnO2 nanoparticles show the occurrence of O-Mn-O vibrational mode at around 515 cm-1. Based on the spectral and morphological data confirms the prepared compounds are nanometer in size. The structural investigation of MnO2 nanoparticles using the powder X-ray diffraction method reveals that the nanoparticles have a tetragonal configuration. Powder X-ray diffraction measurements were used to estimate crystallite grain diameter. The size of the crystalline grains is 7.5 nm. The PA-MnO2 nanoparticles demonstrated enhanced antibacterial activity against various gram positive bacteria like as S. aureus, S. pneumoniae, Stap. Pneumoniae and B. subtilis and various gram negative bacterial strains like as E. coli, K. pneumoniae, p. mirabilis and P. aeruginosa than standard drug ciprofloxacin. Antifungal activity of PA-MnO2 nanoparticles exhibited abnormal character against various fungal strains such as A. niger, C. albicans, C. tropicalis and M. campestris than the standard drug nystatin. Free radical scavenging study by DPPH assay showed enhanced activity by increasing the concentration of PA-MnO2. This study shows simple and eco-friendly synthesis of PA-MnO2 nanoparticles by plant extract. PA-MnO2 nanoparticles by green approach have potential to resolve emerging drug resistance against pathogenic diseases.

Определение частных порядков реакции восстановления перманганата калия этанолом в различных средах

A spectrophotometric kinetic study of the reaction of the potassium permanganate reduction by excess ethanol in acidic, neutral and alkaline environments was performed. The reaction mixtures were prepared from the solutions of potassium permanganate of different concentrations (0.0004, 0.001 and 0.002 М) and either the solutions of sulphuric acid (1, 3 and 10 %), water, or the solutions of sodium hydroxide (0.01, 0.04 and 0.1 М). The kinetic curves were recorded with the spectrophotometer at the wavelengths of 525 nm (in acidic environment), 400 nm (in neutral environment) and 605 nm (in alkaline environment). The initial reaction rates were determined from the slopes of the initial linear parts of the kinetic curves. Using the differential van’t Hoff method, the partial reaction orders were determined. It was shown that in the acidic environment the partial reaction order with respect to permanganate is close to 1.5, and that with respect to hydrogen ions is close to 0.6. In the neutral and alkaline environments the reaction obeys the first partial order with respect to permanganate, and the partial order of the reaction in alkaline environments with respect to hydroxyl-ions is close to 0.8. It was also shown that the effective rate constants of the reaction in acidic and alkaline environments are significantly higher than that in neutral environment

Revisiting the permanganate oxidizable carbon (POXC) assay assumptions: POXC is lignin sensitive

AbstractPermanganate oxidizable carbon (POXC) is a popular soil health test developed to measure “labile” C via the reduction of permanganate, dependent on several stoichiometric reduction oxidation assumptions. As a proof‐of‐concept experiment to evaluate the interpretation of POXC as “labile” C, we tested 17 compounds ranging in biological lability under standard POXC assay conditions at a fixed C mass (25 mg) in a quartz (2–0.053 mm diameter) matrix. POXC was high for lignin, whereas carbohydrates did not differ from the quartz control. Functional group‐based reactivity partly explained permanganate reduction. These findings indicate that (i) POXC is not a labile C fraction and (ii) corroborate previous concerns that the stoichiometric oxidation–reduction assumptions in the calculation of C oxidation from permanganate reduced are not sound. POXC interpretation should regard POXC as a chemically defined fraction, report in units of moles permanganate reduced per kg soil, and avoid terms such as “labile” and “active.”

Cerium modified birnessite-like MnO2 for low temperature oxidation of formaldehyde: Effect of calcination temperature

Cerium modified birnessite-like MnO2 were synthesized (CexMn; x = 0.01; 0.1) from a simple and inexpensive redox method involving the reduction of potassium permanganate by sodium lactate in the presence of Ce(NO3)3 at ambient temperature. The as-synthesized samples were calcined at different temperatures (Tc: 200, 300 and 400 °C) to be tested in HCHO total oxidation in dry air at low temperature. The Ce0.01Mn catalyst calcined at 400 °C showed the best catalytic activity in HCHO oxidation with a T50 (temperature at which 50 % of HCHO was converted into CO2) of 50 °C and was found to be air and moisture stable (up to 75 %RH) upon time. The beneficial effects of a calcination step at 400 °C allowed to get enhanced asymmetric Ce-O-Mn surface interactions along with highly dispersed Ce4+/3+ related species and enhanced TCMn3+ (TC: triple corner) amounts which contributed to a great extent for its high activity in HCHO oxidation.

Spectrophotometric assay of oxymetazoline-HCl in pure form and in its pharmaceutical formulations using potassium permanganate.pdf

This study involves the development of two sensitive and reproducible spectrophotometric methods to determine oxymetazoline- HCl in pure form and its dosage forms. Both spectro-photometric methods were based on the reduction of potassium permanganate with oxymet-azoline- HCl.In method (A), oxymetazoline-HCl was reacted with an excess known amount of potassium permanganate in an acid solution of H2SO4 and the absorbance of unreacted potassium per-manganate was measured at 545 nm. In method (B) the oxidation reaction of oxymetazoline- HCl was carried out in an alkaline solution of sodium hydroxide and the absorbance of the resulting (MnO2) was measured at 610 nm. In method (A), the amount of potassium perman-ganate reacted corresponds to the oxymetazoline-HCl content and the intensity of absorb-ance decreased linearly with the concentration, while in method (B), the intensity of absorb-ance was increased linearly with concentration.Under optimum conditions, Beer’s law was found to be linear in the concentration range of 1.0-30 and 0.5-3.5 μg/ml with molar absorptivity 0.64×104 and 3.16×104 l.mol-1cm-1and cor-responding to Sandell's sensitivity values of 0.0448 and 0.0090 μg/cm2 for both methods (A) and (B), respectively. The detection limit (LOD) and quantification limit (LOQ) have also been estimated. Accuracy for pure OXM was calculated and found in the range -0.7% to 0.8% and-2.68% to 0.614%, while the precision (RSD) was <0.176% and <0.929% for method (A) and method (B), respectively. The two suggested methods (A) and (B) were successfully applied to the determination of oxymetazoline -HCl in bulk and its pharmaceutical preparations (drops and spray) with accurate and accepted results.

Multifunctional hemoporfin-Cu9S8-MnO2 for magnetic resonance imaging-guided catalytically-assisted photothermal-sonodynamic therapies

Integrated theranostic nanoplatforms with multi-model imaging and therapeutic functions are attracting great attention in cancer treatments, while the design and preparation of such nanoplatforms remain an open challenge. Herein, we report hemoporfin@Cu9S8@MnO2 nanoparticles (H@Cu9S8@MnO2 NPs) as multifunctional nanoplatforms for magnetic resonance imaging-guided catalytically-assisted photothermal-sonodynamic therapies of tumors. Cu9S8 hollow spherical nanoparticles were firstly prepared by in-situ vulcanization of Cu2O, and the growth of MnO2 shell was realized by the reduction of manganese permanganate, where the hollow structure of Cu9S8 could be used to load hemoporfin sonosensitizer. Cu9S8@MnO2 nanoparticles with diameters of ∼ 130 nm exhibit increased photoabsorption in near-infrared (NIR) region (680–1100 nm) due to the plasmonic effect of Cu9S8, and the photothermal conversion efficiency is determined to be 32.5% under 1064 nm laser irradiation. Furthermore, MnO2 shells can mimic catalase to trigger the decomposition of endogenous H2O2 into O2 with a significant O2 elevation (14.7 mg L-1) within 8 min and then promote the production of 1O2 via sonodynamic effect of hemoporfin. Meanwhile, MnO2 shells provide the T1-weight magnetic resonance (MR) imaging function. When H@Cu9S8@MnO2 NPs solution is administered to the mice, the tumor growth can be effectively inhibited due to catalytically-assisted synergetic photothermal-sonodynamic therapies which have superior therapeutic effect compared to mono-model therapy alone. Thus, H@Cu9S8@MnO2 NPs present a promising strategy for the development of integrated theranostic nanoplatforms with multi-model imaging and therapy functions.

Performance and mechanism of hydrogen evolution from room-temperature thermal catalytic water splitting by α-phase Si3N4

Because α-Si3N4 has a noncentrosymmetrical crystal pattern capable of self-polarizing point groups, it is theoretically pyroelectric. When the ambient temperature changes, the surface of a pyroelectric semiconductor will produce abundant compensationary charges q+ and q-, which theoretically can be used into hydrogen evolution from water splitting. In this study, the piezoelectric and pyroelectric performances of α- Si3N4were validated by piezoelectric force microscopy and potassium permanganate reduction experiments. Based on the pyroelectric performance of α- Si3N4 and with methanol as the sacrificial agent, hot–cold cycles were conducted from room temperature (27 °C) to 60 °C. Per gram of catalysts can produce 12.32 μmol/g hydrogen after 20 cycles, and the hydrogen yields after repeated experiments did not significantly decrease, proving that Si3N4 has high stability and that the pyroelectric effect is highly potential for hydrogen production from water splitting.

Preparation and Optimization of MnO2 Nanoparticles

Manganese dioxide (MnO2) is one of the commonly applied inorganic material which is gaining increasing attentions in recent years. However, preparation and optimization of MnO2 nanoparticles have rarely been studied by previous studies, making the mechanisms responsible for preparation of MnO2 remaining largely unknown. Here in this study, we synthesized MnO2 through reduction of potassium permanganate (KMnO4) using different reductants, including protein, polymers and small molecule organic acids. It was suggested that, stable MnO2 nanoparticles can only be obtained in balanced synthesis/stabilization process which requires the reductant to have proper reducibility and stabilization ability at the right charge ratios. Our results concluded that, among these materials, polyvinylpyrrolidone (PVP) K30 showed the best performance at the charge ratio of 8/3 (w/w, PVP K30 to KMnO4, under given reaction conditions, which resulted in nanoparticles (hydrodynamic size: 79.72±31.53) with high stability and well dispersity, which was then selected as the optimal formulation.

Biogenesis of MnO2 Nanoparticles Using Momordica Charantia Leaf Extract

In this present study, an easy, eco-friendly, and efficient method for the biogenesis of manganese dioxide nanoparticles (MnO2 NPs) using Momordica charantia leaf extract is discussed. The MnO2 NPs were synthesised by reduction of potassium permanganate using Momordica charantia leaf extract as a reducing agent. Fourier-transform infrared spectra exposed the contribution of the biomolecules in the Momordica charantia leaf extract for the formation of MnO2 NPs. The UV–visible spectrum of the biosynthesized MnO2 NPs displayed absorption peaks at 371 nm, which was the absorption maximum of MnO2 NPs. Crystal phase and crystalline size of the biosynthesized MnO2 NPs was characterized by X-ray diffraction analysis. The X-ray diffraction pattern indicated that the average size of MnO2 NPs was about 36.01 nm. The field emission scanning electron microscopy analysis revealed that the biosynthesized MnO2 NPs have irregularly spherical shape with 16 – 63 nm in size. EDAX confirmed the presence of Mn and O in the MnO2 NPs. The antibacterial activities of MnO2 NPs were evaluated against Bacillus amyloliquefaciens, Bacillus subtilis, and Bacillus cereus. The total antioxidant capacity was evaluated by phosphomolybdenum method. The biosynthesized MnO2 NPs have significant antibacterial activity and antioxidant activity.

Green Synthesis of MnO2 NPs Using Blumea lacera Leaf Extract and its Antimicrobial Study

Background: Green synthesis of nanoparticles has emerged as an interesting and expanding research area due to environmental friendliness, non-toxicity, cleanliness, and cost-effectiveness. Moreover, it can be performed at room pressure and temperature. Blumea lacera is described as a valuable medicinal plant in many vital systems of medicines. The study explored the eco-friendly green synthesis of MnO2 NPs using Blumea lacera leaf extract. Methods: Reduction of potassium permanganate (KMnO4) using Blumea lacera leaf extract was carried out at room temperature. The crude extract of Blumea lacera was added to metal ion reagents of specific volume and specific concentration at ambient temperature and stirred continuously using a magnetic stirrer. The aqueous leaf extract reduced and stabilized the KMnO4 into MnO2 NPs. The MnO2 NPs obtained from the solution were purified and separated by repeated centrifugation using Remi cooling centrifuge model C-24. Results: The biosynthesized MnO2 NPs characterized by UV–Vis spectroscopy showed an absorption peak at 400 nm. The XRD studies revealed the spherical shape of MnO2 NPs with an average particle diameter of 20 nm. FT-IR analysis confirmed the presence of functional groups -OH, C=O, C=C, and CH triggering the synthesis of MnO2 NPs. Vibrational mode at around 606.62 and 438.81 cm−1 supports the occurrence of the O–Mn–O bond. Conclusion: The synthesized MnO2 NPs were found to be good antibacterial and antifungal agents against bacterial strains Staphylococcus aureus, B. subtilis, Pseudomonas aeruginosa, E. coli, and fungal strains C. albicans, Aspergillus niger, and Sclerotium rolfsii.

Coupled adsorption-catalytic reduction of permanganate on Co–Al-layered double hydroxide for dye removal

Permanganate (MnO4−) ions were catalytically reduced to MnO2 by water molecules after adsorption on the surface of carbonate intercalated Co–Al-LDH. This reaction was very slow under experimental conditions in the absence of catalyst and was catalyzed by Co–Al-LDH and Co(II) ion had a key role in this process in the pH range of 2.8–13. But, at pH = 14, MnO4− ions reacted with Co(II) ion of adsorbent and produced Co(III). At all pHs, adsorption sites of Co–Al-LDH for MnO4− ions were Co–OH groups. These adsorption sites were located in micropores and mesopores of Co–Al-LDH and were called MI and ME adsorption sites, respectively. MnO4− ions were adsorbed on both adsorption sites in neutral aqueous solutions and only on ME sites at other pHs. Adsorption experiments were carried out at different temperatures, ionic strengths, pHs and initial adsorbate concentrations. Co–Al-LDH acted as a superadsorbent for MnO4− ions and maximum adsorption capacity was 347.9 mg g−1 (2.2 mmol g−1) in neutral aqueous solution at 318 K. The adsorption binding constants and thermodynamic parameters of adsorption of MnO4− ions on Co–Al-LDH were analyzed by ARIAN (adsorption isotherm regional analysis) model. This model determined the boundaries of adsorption of MnO4− ions on Co–Al-LDH under different conditions and showed that this process was endothermic in regions I and II of its isotherms in neutral solution and at pH = 13. This process obeyed ARIAN–Hinshelwood mechanism and water molecules in the pH range of 2.8–13 and hydroxide ions at pH = 14 participated as nucleophile reagents. Reaction in the pH range of 2.8–13 was as follows2MnO4−+ H2O →2MnO2(ad)+32O2+2OH− and at pH = 14 was as2MnO4−+2Co(II)–OH+H2O→2Co(III)–OH+2MnO2ad+32O2+2OH−This adsorbent was used for selective separation of permanganate from cationic safranin O and methylene blue dyes. However, it could not separate anionic methyl orange dye from MnO4− ions.This work further successfully demonstrated an approach to recycle the used Co–Al-LDH using a reducing agent.

An agar-based bioassay for accurate screening of the total antioxidant capacity of lactic acid bacteria cell-free supernatants

This study aims to develop a new, simple, and efficient method for estimating the total antioxidant capacity of lactic acid bacteria-cell free supernatant. The bioassay is based on diffusion and reduction of permanganate in agar medium under acidic conditions where the Mn7+ ions are quantitatively oxidized to Mn2+ and shift from an intense purple color to colorless. Hence, the reaction enables fast detection of the bleaching diameter during diffusion of the sample in permanganate agar. This bleaching diameter is correlated to the reducing power of the substance tested. The method was tested and validated to quantify the total antioxidant capacity of culture supernatants of probiotic strains (Lacticaseibacillus rhamnosus LGG and Lactiplantibacillus plantarum 299v) and 25 lactic acid bacteria isolated from a human intestinal origin and compared to the PRAC and DPPH methods. The results were treated statistically by analysis of variance. This method proved to be linear (R2 in the linear experiment of ascorbic acid was 0,99), precise with repeatability intraday RSD of 2.07 to 5.5% and intermediate precision RSD of 2.95 to 5.53%, and accurate (100.29 to 108.58%) at 30 min, 1 h, and 4 h in the selected range of 1.5–5.5 mM of ascorbic acid. The developed permanganate agar reduction bioassay is a fast, reliable, and cost-effective technique for the prescreening and detecting the total antioxidant capacity of supernatants of lactic acid bacteria and possibly other sources of natural antioxidants.

Nitrocellulose redox permanganometry: A simple method for reductive capacity assessment

We propose a rapid, simple, and robust method for measurement of the reductive capacity of liquid and solid biological samples based on potassium permanganate reduction followed by trapping of manganese dioxide precipitate on a nitrocellulose membrane. Moreover, we discuss how nitrocellulose redox permanganometry (NRP) can be used for high-throughput analysis of biological samples and present HistoNRP, its modification used for detailed analysis of reductive capacity spatial distribution in tissue with preserved anatomical relations.•NRP is a rapid, cost-effective, and simple method for reductive capacity assessment•NRP is compatible with a high-throughput screening of solid and liquid biological samples•HistoNRP exploits passive diffusion slice print blotting for reductive capacity spatial analysis

MnO2/CoO electrode for supercapacitor: Synthesis and electrochemical performance

In this work, Cobalt Oxide (CoO) was prepared by co-precipitation method by taking 1:3M of Co (NO3)2·6H2O and NaOH. Synthesis of Manganese dioxide (MnO2) was done by reduction of potassium permanganate (KMnO4) with aqueous sulphuric acid (H2SO4) by hydrothermal process. For making the coin cell capacitor CoO and MnO2 were spin-coated on the thin copper sheet which was used as the current collector, PEDOT: PSS poly (3,4 – ethylene dioxythiophene) as electrolyte and cellulose paper as a separator. Scanning electron microscopy (SEM) analysis has been employed to study surface morphology and to confirm the formation of nanoparticles. An image analysis approach using ImageJ has been used to measure the percentage of porosity from the SEM micrographs. The parameters like specific capacitance, energy density, and power density were calculated from the CV measurements and were compared. When both electrodes are MnO2, it has a specific capacitance of 33.57F/g, the energy density of 16.84 J/g, and power density of 4.21 W/g and when both electrodes are CoO it has a specific capacitance of 29.19F/g, the energy density of 14.59 J/g and power density of 3.65 W/g. But one side with MnO2 and the other side with CoO electrode shows a specific capacitance of 44.92F/g, an energy density of 22.46 J/g, and a power density of 5.62 W/g.