Aqueous Permanganate Solution Research Articles

Elucidating atomic emission and molecular absorption spectra using a basic CD spectrometer: a pedagogical approach for secondary-level students

Abstract Spectroscopy has held a pivotal role in advancing our comprehension of chemistry, dating back to its inception by Robert Bunsen and Gustav Kirchhoff. Nonetheless, access to advanced spectrometers remains restricted, particularly in high schools within developing nations. In this laboratory experiment, students were guided to fashion a spectrometer using reusable materials. This uncomplicated contrivance facilitated the exploration of emission and absorption spectroscopy, acquainting students with atomic spectra marked by electronic transitions, yielding line spectra. Conversely, molecules display not solely electronic transitions, but also vibrational and rotational shifts within chemical bonds, culminating in band spectra. Mobile phone cameras were enlisted as detectors. Captures of sodium and copper atoms emitting light in the course of a flame test, as well as depictions of molecular entities (copper sulphate pentahydrate and potassium permanganate aqueous solutions) absorbing light, were transmuted into the RGB (Red-Green-Blue) color model channels. The learning outcomes exhibited that 86 % of the students successfully discerned between an atomic spectrum and a molecular spectrum. Furthermore, 93 % of the students indicated that the incorporation of mobile devices in fostering scientific comprehension effectively seized their attention, resulting in heightened levels of engagement.

Preparation of layered manganese dioxide nanoparticles by microwave discharge in liquid: a simple, rapid and direct synthetic method

Manganese dioxide is one of the key materials in battery, adsorption media, and catalytic materials in the environmental field because of its excellent properties. In this investigation, new synthetical technology—the microwave discharge plasma in liquid method was used directly to make manganese dioxide with potassium permanganate (KMnO4) solution. The synthesis was realized in one step by the microwave discharging plasma in potassium permanganate aqueous solution without using any dispersants or stabilizers. The reduction time was very short, it only takes 3 min to complete the reduction of the 0.2 mmol l−1 potassium permanganate solution for the formation of MnO2. The structure characteristics and adsorption-desorption curves were studied by X-ray diffractometer (XRD), transmission electron microscopy and x-ray photoelectron spectroscopy, XRD, etc. it was found that the synthesized manganese dioxide nano-sheet had a layered structure and a large specific surface area (248.89 m2 g−1). The methylene blue was used to validate the effectiveness of the prepared manganese dioxide. The results showed that the synthesized manganese dioxide had good adsorption and photocatalytic properties. In conclusion, the microwave liquid-phase discharge plasma is a very effective reduction method with potential development.

Oxidation of Propane-1,3-diol (Non-Vicinal) by Potassium Permanganate in Aqueous Medium. A Kinetic Study

The oxidation of propane-1,3-diol by potassium permanganate in aqueous solution was investigated at λmax 525 nm. The rate of the reaction was found to increase with increase in [KMnO4] and [Propane-1,3-diol]. The reaction showed first order dependence each in [KMnO4] and [Propane-1,3-diol] and independent in the ionic strength of the solution. The values of 〖∆H〗^#(kJ mol-1), 〖∆S〗^# (kJK-1mol-1) and〖 ∆G〗^#(kJmol-1) were 24.98, -0.22 and 90.50 respectively. Negative entropy of activation revealed an ordered transition state for the reaction. Spectroscopic studies and FTIR analysis revealed the product of the reaction to be 3-hydroxyl-propanal.

Mechanistic Study on Graphene Oxidation by KMnO4 in Solution Phase and Resultant Carbon–Carbon Unzipping

We reveal the origins of surface groups on pristine and defective graphene after oxidation with potassium permanganate in aqueous solution. Density functional theory calculations show that the hydr...

The electronic structure of the aqueous permanganate ion: aqueous-phase energetics and molecular bonding studied using liquid jet photoelectron spectroscopy

Permanganate aqueous solutions, MnO4-(aq.), were studied using liquid-micro-jet-based soft X-ray non-resonant and resonant photoelectron spectroscopy to determine valence and core-level binding energies. To identify possible differences in the energetics between the aqueous bulk and the solution-gas interface, non-resonant spectra were recorded at two different probing depths. Similar experiments were performed with different counter ions, Na+ and K+, with the two solutions yielding indistinguishable anion electron binding energies. Our resonant photoelectron spectroscopy measurements, performed near the Mn LII,III- and O K-edges, selectively probed valence charge distributions between the Mn metal center, O ligands, and first solvation shell in the aqueous bulk. Associated resonantly-enhanced solute ionisation signals revealed hybridisation of the solute constituents' atomic orbitals, including the inner valence Mn 3p and O 2s. We identified intermolecular coulombic decay relaxation processes following resonant X-ray excitation of the solute that highlight valence MnO4-(aq.)-H2O(l) electronic couplings. Furthermore, our results allowed us to infer oxidative reorganisation energies of MnO4˙(aq.) and adiabatic valence ionisation energies of MnO4-(aq.), revealing the Gibbs free energy of oxidation and permitting estimation of the vertical electron affinity of MnO4˙(aq.). Finally, the Gibbs free energy of hydration of isolated MnO4- was determined. Our results and analysis allowed a near-complete binding-energy-scaled MnO4-(aq.) molecular orbital and a valence energy level diagram to be produced for the MnO4-(aq.)/MnO4˙(aq.) system. Cumulatively, our mapping of the aqueous-phase electronic structure of MnO4- is expected to contribute to a deeper understanding of the exceptional redox properties of this widely applied aqueous transition-metal complex ion.

Mn(III)-ligand complexes as a catalyst in ligand-assisted oxidation of substituted phenols by permanganate in aqueous solution

Ligands can significantly increase the oxidation rates of phenolic compounds by MnO4−. This was often explained by the in situ formed Mn(III)- or Mn(X)-ligand complexes that can oxidize phenols faster than MnO4− can. This work discovered that Mn(III)-ligand complexes also acted as a catalyst for the oxidation of phenolic compounds by MnO4− (i.e., the catalytic role of Mn(III)-ligand). First, when phenol was mixed with MnO4− and pyrophosphate (PP, a representative ligand), Mn(III)-PP was found to form while phenol was quickly oxidized. However, the amount of phenol that was directly oxidized by Mn(III)-PP only accounted for ∼25% of phenol that was oxidized in the mixture, indicating that there were other pathways. Then, when pentachlorophenol (PCP) was used as another phenolic probe, the externally prepared Mn(III)-PP was observed to only slightly oxidize PCP, but its addition significantly accelerated PCP oxidation by MnO4−. The Mn(III)-PP concentration also remained unchanged during the above reaction, thus suggesting the catalyst role of Mn(III)-PP. This new pathway was further validated by successfully explaining all the experimental observations obtained so far, including the effect of pH, effects of different ligand amounts and types, product patterns, and the induction period. Finally, possible catalytic mechanisms of Mn(III)-ligand were discussed based on the experimental results.

Reduction behaviors of permanganate by microbial cells and concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2+

Permanganate treatment is widely used for disinfection of bacteria in surface-contaminated water. In this paper, the fate of the dissolved permanganate in aqueous solution after contact with cells of Pseudomonas fluorescens was studied. Concomitant accumulation of divalent cations of Mg2+, Zn2+, and Co2+ during precipitation of Mn oxides was also studied. The time course of the Mn concentration in solution showed an abrupt decrease after contact of Mn(VII) with microbial cells, followed by an increase after ~24 hr. XRD analysis of the precipitated Mn oxides, called biomass Mn oxides, showed the formation of low-crystalline birnessite. Visible spectroscopy and X-ray absorption near edge structure (XANES) analyses indicated that dissolved Mn(VII) was reduced to form biomass Mn oxides involving Mn(IV) and Mn(III), followed by reduction to soluble Mn(II). The numbers of electron transferred from microbial cells to permanganate and to biomass Mn oxides for 24 hr after the contact indicated that the numbers of electron transfer from microbial cell was approximately 50 times higher to dissolved permanganate than to the biomass Mn oxides in present experimental conditions. The 24 hr accumulation of divalent cations during formation of biomass Mn oxides was in the order of Co2+ > Zn2+ > Mg2+. XANES analysis of Co showed that oxidation of Co2+ to Co3+ resulted in higher accumulation of Co than Zn and Mg. Thus, treatment of surface water by KMnO4 solution is effective not only for disinfection of microorganisms, but also for the elimination of metal cations from surface water.

A facile one-pot hydrothermal synthesis as an efficient method to modulate the potassium content of cryptomelane and its effects on the redox and catalytic properties

Cryptomelane has been widely applied as catalyst in oxidation reactions due to its excellent redox properties and low cost. Here, a novel one-pot hydrothermal synthesis using a potassium permanganate aqueous solution as precursor and ethanol as reducing agent has successfully been developed to obtain cryptomelane nano-oxides. This synthetic route makes it possible to control the amount of potassium incorporated into the structure of the cryptomelane by selecting the appropriate synthesis temperature and ethanol initial concentration. Taking advantage of this approach, the effect of potassium concentration on the structural stability and reducibility of the cryptomelane, which are poorly discussed in the literature, has been studied. We have observed that samples with low content of potassium (∼11%) show high conversions of CO to CO2 especially at low temperatures. The lower activity of the samples with high K contents (∼16%) can be ascribed to the beneficial effect of K on the structural stability of cryptomelane in detriment of labile oxygen on cryptomelane surface.

Kinetics and Mechanism of Propane-1,3-diol Oxidation by Mn(VII) in Aqueous Medium

The oxidation of propane-1,3-diol by potassium permanganate in aqueous solution was investigated at λmax 525 nm. The rate of the reaction was found to increase with increase in [KMnO4] and [Propane-1,3-diol]. The reaction showed first order dependence each in [KMnO4] and [Propane-1,3-diol] and independent in the ionic strength of the solution. The values of 〖∆H〗^#(kJ mol-1), 〖∆S〗^# (kJK-1mol-1) and〖 ∆G〗^#(kJ mol-1) were 24.98, -0.22 and 90.50 respectively. Negative activation of entropy revealed an ordered transition state for the reaction. Spectroscopic studies and FTIR analysis revealed the product of the reaction to be 3-hydroxy-propanone. A suitable reaction mechanism is proposed for the reaction investigated.

Crosslinked MnO 2 Nanowires Anchored in Sulfur Self‐Doped Porous Carbon Skeleton with Superior Lithium Storage Performance

A facile process for the in-situ anchoring of crosslinked MnO2 nanowires (MNs) in a preformed sulfur self-doped porous carbon material (SPC) derived from antibiotic bacterial residues (ABRs) was developed, only involving impregnation of potassium permanganate aqueous solution into SPC and consequently occurring in-situ redox reaction at room-temperature. In the obtained [email protected] composite, SPC serves as a conductive collector for accelerating lithium-ion transfer and a buffer carrier for reliving the volume-expansion of MNs, and the in-situ formed MNs homogeneously anchored in SPC can fully imply potential electrochemical properties and enable the whole skeleton more stable to guarantee good cycling stability. The proposed approach can not only solve the environmental problems associated with the accumulation of ABRs, but also achieve the maximization of dual energy storage and conversion of the [email protected] composite by elaborately utilizing the combinative merits of SPC and MNs. As a result, the [email protected] composite shows a reversible capacity of 953.4 mAh/g at 0.2 A/g after 80 cycles, and 745.9 mAh/g at 1 A/g after 450 cycles when used as anode for lithium-ion batteries.

Voltammetric determination of trace amounts of permanganate at a zeolite modified carbon paste electrode

A novel sensitive, simple and fast method is suggested for indirect voltammetric determination of permanganate in aqueous solution.

High-yield preparation of K-birnessite layered nanoflake

A high-yield and facile approach for producing K-birnessite layered nanoflake was proposed via simply mixing and hydrothermally heating the mixture of potassium oxalate and potassium permanganate aqueous solution. The product yield was proved to be significantly increased with the addition of potassium oxalate, and the possible reason was also discussed. The product was confirmed to be K-birnessite by a series of characterizations, and fabricated on nickel foam to study the electrochemical behaviors as active electrode material for supercapacitor. Electrochemical results showed that the product exhibited well-performed charge storage properties, and could be promising for applications in energy storage devices.

Synthesis of colloidal MnO2with a sheet-like structure by one-pot plasma discharge in permanganate aqueous solution

Stable colloidal MnO2—consisting of MnO2with a sheet-like structure—was synthesized by solution plasma process (SPP) in one-step and without utilizing any dispersants or stabilizers.

Activated carbon/manganese dioxide hybrid electrodes for high performance thin film supercapacitors

We combine the activated carbon (AC) and the manganese dioxide (MnO2) in a AC/MnO2 hybrid electrode to overcome the low capacitance of activated carbon and MnO2 by exploiting the large surface area of AC and the fast reversible redox reaction of MnO2. An aqueous permanganate (MnO4−) is converted to MnO2 on the surface of the AC electrode by dipping the AC electrode into an aqueous permanganate solution. The AC/MnO2 hybrid electrode is found to display superior specific capacitance of 290 F/g. This shows that supercapacitors classified as electric double layer capacitors and pseudocapacitors can be combined together.

Influence of potassium permanganate pretreatment on mechanical properties and thermal behavior of moso bamboo particles reinforced PVC composites

To illustrate the mechanism of oxidizer treatment on wood cellulose reinforced plastic composites, moso bamboo particles were modified with potassium permanganate aqueous solutions and then filled in polyvinyl chloride (PVC) matrix. Mechanical properties and thermal behaviors of moso bamboo particles reinforced PVC composites (BPPC) were investigated. Results showed that tensile strength of BPPC achieved its maximum value of 13.79 MPa with 0.5% potassium permanganate treatment while modulus of rupture and modulus of elasticity reached their highest values of 30.36 MPa and 3261.89 MPa, respectively, at 0.2% concentration. Potassium permanganate treatment enhanced elongation at break and flexural deformation of BPPC. The melting temperature reached 190.8°C with 0.5% potassium permanganate treatment and the melting enthalpy of crystallization was reduced to 69.82 J/g with 0.2% potassium permanganate treatment. A uniform dispersion of moso bamboo particles in PVC matrix was obtained after potassium permanganate treatment. Low concentration potassium permanganate would oxidize hydroxyl groups of moso bamboo cellulose while too high concentration would degrade moso bamboo cellulose. POLYM. COMPOS., 35:1460–1465, 2014. © 2013 Society of Plastics Engineers

On the Photoabsorption by Permanganate Ions in Vacuo and the Role of a Single Water Molecule. New Experimental Benchmarks for Electronic Structure Theory

We report electronic spectra of mass-selected MnO4(-) and MnO4(-)⋅H2O using electronic photodissociation spectroscopy. Bare MnO4(-) fragments by formation of MnO3(-) and MnO2(-), while the hydrated complex predominantly decays by loss of the water molecule. The band in the visible spectral region shows a well-resolved vibrational progression consistent with the excitation of a Mn-O stretching mode. The presence of a single water molecule does not significantly perturb the spectrum of MnO4(-). Comparison with the UV/Vis absorption spectrum of permanganate in aqueous solution shows that complete hydration causes a small blueshift, while theoretical models including a dielectric medium have predicted a redshift. The experimental data can be used as benchmarks for electronic structure theory methods, which usually predict electronic spectra in the absence of a chemical environment.

DFT Study of Trichloroethene Reaction with Permanganate in Aqueous Solution

The mechanism of the environmentally important reaction between permanganate anion and trichloroethene (TCE) has been studied theoretically using modern DFT functional. It has been shown that IEFPCM/M05-2X/aug-cc-pVDZ theory level yields activation parameters and carbon isotopic fractionation factor in excellent agreement with the experimental data. Obtained results indicate that this reaction proceeds via the 3+2 mechanism with a very early transition state, in which the new C-O bonds are formed only in about 20%. An alternative, stepwise mechanism that involves initial formation of a single new C-O bond and a C-Mn bond, followed by rearrangement to the permanganate-TCE adduct, has been found to be more energetically demanding and in disagreement with the experimental isotopic fractionation.

Kinetics of oxidation of d-glucose by permanganate in aqueous solution of cetyltrimethylammonium bromide

The catalytic effect of cetyltrimethylammonium bromide (CTAB) on the permanganate oxidation of d-glucose has been studied spectrophotometrically in presence of sulphuric acid. It was observed that the reaction proceeds in two stages (a slow step followed by a relatively fast second step). The influence of different parameters was measured i.e., [reactants], [surfactant], [sulphuric acid] and temperature. The absorbance of the reaction mixture increases with [CTAB] which suggests the association of permanganate with the cationic head group of CTAB. The effect of [surfactant] on the rate constants was explained in terms of the pseudo phase model proposed by Menger and Portnoy and modified by Bunton et al. On the basis of observed kinetic results, a suitable mechanism has been proposed.

MnO2-Embedded-in-Mesoporous-Carbon-Wall Structure for Use as Electrochemical Capacitors

We present an in situ reduction method to synthesize a novel structured MnO(2)/mesoporous carbon (MnC) composite. MnO(2) nanoparticles have been synthesized and embedded into the mesoporous carbon wall of CMK-3 materials by the redox reaction between permanganate ions and carbons. Thermogravimetric analysis (TG), X-ray photoelectron spectrum (XPS), X-ray diffraction (XRD), nitrogen sorption, transmission electron microscopy (TEM), and cyclic voltammetry were employed to characterize these composite materials. The results show that different MnO(2) contents could be introduced into the pores of CMK-3 treated with different concentrations of potassium permanganate aqueous solution, while retaining the ordered mesostructure and larger surface area. Increasing the MnO(2) content did not result in a decrease in pore size from the data of nitrogen sorption isotherms, indicating that MnO(2) nanoparticles are embedded in the pore wall, as evidenced by TEM observation. We obtained a large specific capacitance over 200 F/g for the MnC composite and 600 F/g for the MnO(2), and these materials have high electrochemical stability and high reversibility.

水熱法によるアルミニウム上への酸化触媒能を有するＭｎＯ２‐ベーマイト複合皮膜の作製

Aluminum has excellent workability and surface finishing, but it corrodes easily and has low hardness. In this study, a high corrosion resistance oxide film was prepared first by hydrothermal treatment on aluminum in the primary treatment. Subsequently, nano MnO2 particles were immobilized on minute high corrosion resistance oxide film by hydrothermal treatment. Specifically aluminum was maintained for 30 minutes under 483 K (2.0 MPa) conditions in a 0.04 mol/l aluminum nitrate aqueous solution by hydrothermal treatment. Then, MnO2 was immobilized by hydrothermal treatment for 30 minutes under 453-483 K (1.0-2.0 MPa) conditions in a potassium permanganate aqueous solution on the boehmite film. A thick boehmite film (20 μm) was prepared by adding aluminum nitrate formed globules in the primary treatment, and it possessed wide surface area. Nano MnO2 particles (30 nm) were immobilized onto the boehmite film in a potassium permanganate aqueous solution by hydrothermal treatment in the secondary treatment. In this manner a MnO2-boehmite composite film with wide surface area and high oxidation activity was prepared successfully and for the first time.