Presence Of KMnO4 Research Articles

Efficient Mineralization of Lithium Bis(pentafluoroethanesulfonyl)imide and Related Electrolyte Fluorochemicals Using Superheated Water.

Lithium bis(pentafluoroethanesulfonyl)imide, Li[N(SO2C2F5)2], a typical fluorochemical aimed at better electrochemical performance of battery electrolytes, in superheated water was studied for its waste treatment. When Li[N(SO2C2F5)2] was reacted in pure superheated water at 300 °C, little F- ions were produced. In contrast, complete mineralization of the fluorine, sulfur, and nitrogen atoms in Li[N(SO2C2F5)2] was achieved when the reaction was performed in the presence of KMnO4. Specifically, when Li[N(SO2C2F5)2] was treated for 18 h with 158 mM of KMnO4, the F- and SO42- yields were 101 and 99%, respectively, and the sum of the NO3- and NO2- yields was 101%. In the gas phase, trace CO2 was detected and no CHF3, which has high global warming potential, was formed. Furthermore, the fluorine, sulfur, and nitrogen atoms in the analogues K[N(SO2C4F9)2] and K[N(SO2CF2)2CF2] also underwent complete mineralization using the same approach.

Tandem Oxidative Dearomatizations of Diphenylanthracene Atropisomers.

The first examples of tandem oxidative dearomatizations of 9,10-diphenylanthracene atropisomers with ortho,ortho'- formyl substituents are presented. In the presence of KMnO4, their stereoselective tandem double oxidation and spirocyclization mainly afford the syn or anti dearomatized 9,10-diphthalide anthracenes. Using Pinnick's reagent and depending on the conditions, the oxidation can mainly lead to the corresponding syn or anti diacids in good yields or to three oxidation products. An unprecedented further oxidative ring expansion toward dibenzo[b,e]oxepines is also reported.

The Effect of Septage Sludge and Oxidizing Agents in the Microbial Fuel Cells Generating Electricity

Earlier research demonstrated the efficacy of microbial fuel cells in both wastewater treatment and renewable electric current generation. In this process, microbial fuel cells harness the potential of wastewater as a substrate and energy source, enabling microorganisms to generate electric current. Introducing microorganisms sourced from septage sludge acts as a microbial catalyst. Additionally, tofu wastewater is employed as a nutritional resource to support the growth of these microorganisms. A dual-chamber reactor was utilized to carry out this study, featuring an anode and a cathode connected through a salt bridge. Various substrate variations were performed on the anode, specifically with a combination of tofu liquid waste and septage sludge at ratios of 1:1, 1:2, and 1:3. Additionally, different electrolyte solutions, such as KMnO4 and K3(Fe(CN)6), were used at the cathode. Using different electrolyte solutions as electron acceptors can enhance the electric current production generated. The study spanned 240 hours of operation, during which electric current, voltage, COD, and BOD measurements were taken at 48-hour intervals. The findings revealed that including septage sludge in a 1:3 ratio yielded the highest current strength compared to other substrate variations, measuring 16.34 mA. When using a 0.25 M KMnO4 as an electrolyte solution, the voltage recorded was 8.78 V. Additionally, the most effective removal of COD and BOD content was achieved with a substrate ratio of 1:3 in the presence of KMnO4, achieving removal rates of 95.12% and 96.45%, respectively. These results indicate that adding septage sludge contributes to increased electricity current production.

Permanganate activation with Mn oxides at different oxidation states: Insight into the surface-promoted electron transfer mechanism

The development of new strategies to improve the removal of organic pollutants with permanganate (KMnO4) is a hot topic in water treatment. While Mn oxides have been extensively used in Advanced Oxidation Processes through an electron transfer mechanism, the field of KMnO4 activation remains relatively unexplored. Interestingly, this study has discovered that Mn oxides with high oxidation states including γ-MnOOH, α-Mn2O3 and α-MnO2, exhibited excellent performance to degrade phenols and antibiotics in the presence of KMnO4. The MnO4- species initially formed stable complexes with the surface Mn(III/IV) species and showed an increased oxidation potential and electron transfer reactivity, caused by the electron-withdrawing capacity of the Mn species acting as Lewis acids. Conversely, for MnO and γ-Mn3O4 with Mn(II) species, they reacted with KMnO4 to produce cMnO2 with very low activity for phenol degradation. The direct electron transfer mechanism in α-MnO2/KMnO4 system was further confirmed through the inhibiting effect of acetonitrile and the galvanic oxidation process. Moreover, the adaptability and reusability of α-MnO2 in complicated waters indicated its potential for application in water treatment. Overall, the findings shed light on the development of Mn-based catalysts for organic pollutants degradation via KMnO4 activation and understanding of the surface-promoted mechanism.

Basic Ionic Liquid [Bmim]OH as Efficient Greener Medium for the Oxidation α-Hydroxy Ketone Compounds and Alcohols to Carbonyl Compounds with Potassium Permanganate

In this work, a convenient and greener procedure for synthesizing 1,2-diarylethane-1,2-dione derivatives as well as the oxidation of primary and secondary alcohols was explored using an oxidizing agent (KMnO4) in a basic ionic liquid of 1-butyl-3-methylimidazolium hydroxide ([Bmim]OH) as greener medium. The selective oxidation of α-hydroxy ketone compounds together with primary and secondary alcohols in the presence of KMnO4 in [Bmim]OH afforded corresponding carbonyl compounds of 1,2-diarylethane-1,2-dione derivatives and aldehydes or ketones in high yields (85-97% and 83-97%, respectively). The reactions are mild, fast, and efficient. Moreover, KMnO4 in [Bmim]OH medium was easily recovered and reused for at least four additional reactions without significant loss of efficiency with a consistent yield of about 80%.

Ni-sinapic acid nanocomposite in the selective sensing of permanganate ions

A polyphenolic acid assisted synthesis of Ni nano particles for absorption spectrophotometric sensing of MnO4- ions in micro molar range is reported here. The synthesis was carried out using a green approach where sinapic acid acts as a capping agent. The synthesized nano particle was then characterized using UV–Vis spectroscopy, Fourier transform infrared spectroscopy, transmission electron microscopy, powder X-ray diffraction analysis, X-ray photoelectron spectroscopy. The particle size is around 5 to 10 nm with the presence of both porosity and nano crystallinity as obtained from the transmission electron microscopic analysis. This nano particle can selectively sense permanganate ions in presence of different co-existing ions with the limit of detection (LOD) 0.413 µM. The sensing mechanism was examined with the isothermal titration calorimetry (ITC) and X-ray photoelectron spectroscopy (XPS). Isothermal titration calorimetric data suggests that the interaction between permanganate and the nano particle is enthalpy driven process with ΔH and ΔG values are −80 kcal/mol and −5.72 kcal/mol respectively. XPS data confirmed the presence of Ni(II) ions in the Ni-SA NPs and the atomic percentage of the same differed in presence of KMnO4. There was no significant interference from the contemporary ions and even in the presence of Mn2+ ion. The method has also been applied for the natural water samples and for vegetable. ∼ 88 to 108 % of the added KMnO4 could be recovered from the tap water sample using our prepared methodology. The limit of detection and the present technique are compared with the previously reported literature and have been found to be comparable, even in solvent-free conditions and using simple instrumentation.

Ratiometric fluorescent Si-FITC nanoprobe for immunoassay of SARS-CoV-2 nucleocapsid protein.

Coronavirus disease 2019 (COVID-19) highlights the importance of rapid and reliable diagnostic assays for the management of virus transmission. Here, we developed a one-pot hydrothermal method to prepare Si-FITC nanoparticles (NPs) for the fluorescent immunoassay of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) nucleocapsid protein (N protein). The synthesis of Si-FITC NPs did not need post-modification, which addressed the issue of quantum yield reduction during the coupling reaction. Si-FITC NPs showed two distinct peaks, Si fluorescence at λem = 385 nm and FITC fluorescence at λem = 490 nm. In the presence of KMnO4, Si fluorescence was decreased and FITC fluorescence was enhanced. Briefly, in the presence of N protein, catalase (CAT)-linked secondary antibody/reporter antibody/N protein/capture antibody immunocomplexes were formed on microplates. Subsequently, hydrogen peroxide (H2O2) and Si-FITC NPs/KMnO4 were injected into the microplate together. The decomposition of H2O2 by CAT resulted in remaining of KMnO4, which changed the fluorescence intensity ratio of Si-FITC NPs. The fluorescence intensity ratio correlated significantly with the N protein concentration ranging from 0.02 to 50.00 ng/mL, and the detection limit was 0.003 ng/mL, which was more sensitive than the commercial ELISA kit with a detection limit of 0.057 ng/mL. The N protein concentration can be accurately determined in human serum. Furthermore, the COVID-19 and non-COVID-19 patients were distinguishable by this method. Therefore, the ratiometric fluorescent immunoassay can be used for SARS-CoV-2 infection diagnosis with a high sensitivity and selectivity.Electronic Supplementary MaterialSupplementary material (characterization of Si-FITC NPs (FTIR, HRXPS); stability investigation of Si-FITC NPs (photostability, pH stability, anti-interference ability); stability investigation of free FITC (pH value, KMnO4); quenching mechanism of KMnO4 (UV-vis absorption spectra, fluorescence lifetime decay curves); reaction condition optimization of biotin-CAT with H2O2 (pH value, temperature, time); detection of N protein using commercial ELISA Kit; selectivity investigation of assays for SARS-CoV-2 N protein detection; determination results of SARS-CoV-2 N protein in human serum) is available in the online version of this article at 10.1007/s12274-022-5005-z.

A novel carbon quantum dots-enhanced chemiluminescence method for the sensitive determination of iodide ion

Herein, P and Cl doped carbon dots (P/Cl-CDs) were prepared by a simple hydrothermal method. An obvious chemiluminescence (CL) signal was obtained when the P/Cl-CDs coexisted with acidic KMnO4, and then a stronger CL signal appeared when NaHSO3 was added into the mixed solution of KMnO4 and P/Cl-CDs. The CL property and mechanism of P/Cl-CDs in the presence of KMnO4 or/and NaHSO3 have been elucidated. It was found that iodide ion (I−) could strongly inhibit the CL signal of the P/Cl-CDs-KMnO4-NaHSO3 system, and the degree of inhibition was proportional with the concentration of I−. The finding was used to design a method for the determination of I−. Under the optimum conditions, the CL signal of P/Cl-CDs-KMnO4-NaHSO3 system decreased linearly with the logarithm of I− concentration in a range of 0.1–70.0 μM, and the detection limit was 90.0 nM. The method was applied to the determination of I− in edible salt samples. Conceivably, this novel CL system paves the way to numerous new assays based on the use of heteroatoms doping carbon dots.

New approach of recycling end-of-life reverse osmosis membranes via sonication for microfiltration process

Due to the continuing growth of reverse osmosis (RO) water treatment plants worldwide, the amount of discarded end-of-life (EoL) RO membrane modules is expected to increase drastically in coming years. One of the approaches to address this problem is to transform the EoL membranes for other purposes. In this study, a new approach based on sonication was studied to convert the EoL RO membrane from RO properties into microfiltration (MF) properties, offering a transformation process that was much faster (15 min) than that of typical chemical treatment process (ranging from hours to days) using oxidizing agent solution. Our results indicated that with only 15-min ultrasonication, the properties of EoL RO membrane could be significantly altered, reaching pure water permeability of 172.6 L/m2.h.bar (70-fold increment) with NaCl rejection reduced from ~80% to less than 2%. This is attributed to the deterioration of the polyamide thin selective layer atop the EoL RO membrane. As a comparison, the chemical treatment using 5000-ppm potassium permanganate (KMnO4) solution requires at least 168 h to achieve similar membrane properties. It was also found that the presence of KMnO4 during ultrasonication process could accelerate the rate of polymeric degradation, resulting in even higher pure water permeation. As a conclusion, our work demonstrated a rapid and new approach that is capable of transforming the EoL RO membrane for the filtration process of macromolecules, thus offering a practical solution to address the disposal issues of EoL RO membrane modules.

Innovative approach for the synthesis of graphene/MnO2 nanocomposites and their electrochemical behavior

AbstractGraphene‐manganese dioxide composites were prepared using a simple one step method consisting of the electrochemical exfoliation of graphite in the presence of KMnO4 in 0.1 м H2SO4 at low temperature. In these conditions, the freshly exfoliated graphene sheets (EG) spontaneously reduce the permanganate ions and EG sheets decorated with MnO2 nanoparticles are obtained. This was confirmed by scanning electron microscopy coupled with energy dispersive X‐ray spectroscopy, transmission electron microscopy, X‐ray diffraction, Raman, and X‐ray photoelectron spectroscopies and thermogravimetric analysis. The electrochemical properties of EG@MnO2 material were investigated and discussed. Electrodes based on the composite material exhibited enhanced capacitive performances compared to those made from pure graphene sheets. This was attributed to the synergic effect between the two components (graphene sheets and manganese dioxide nanoparticles) and to a larger porosity of the EG@MnO2 electrode compared to the EG electrode. Additionally, over 91.6% of original capacitance was retained after 4000 cycles, indicating a very good cycling capability of the composite material. Remarkably, the composite electrode showed promising properties in aqueous medium by exhibiting a large and stable operating voltage up 2 V. The results presented in this article could serve as a guide for improving the energy density of supercapacitors in aqueous media.

Ratiometric detection of alkaline phosphatase based on aggregation-induced emission enhancement.

Alkaline phosphatase (ALP) is an important enzyme that is associated with many human diseases, so the quantitative detection of ALP is vital from a clinical perspective. Nevertheless, most fluorescent assays for monitoring ALP depend on aggregation-induced quenching (ACQ), single-signal modulation, or a "signal off" mode, which suffer from poor sensitivity, a "false positive" problem, and low signal output. In this work, we utilized the electrostatically driven self-assembly of glutathione-capped gold nanoclusters (GSH-AuNCs, which show aggregation-induced emission, AIE) and amino-modified silicon nanoparticles (SiNPs) to create a hybrid probe (SiNPs@GSH-AuNCs). This nanohybrid probe showed emission from the SiNPs at around 470nm as well as aggregation-induced emission enhancement (AIEE) of the GSH-AuNCs at 580nm. The AIEE of the GSH-AuNCs was quenched in the presence of KMnO4, but the AIEE was recovered by adding ascorbic acid as an oxidation-reduction reaction occurred between KMnO4 and the ascorbic acid. The fluorescence of the SiNPs remained constant whether the AIEE was quenched or not, meaning that the fluorescence of the SiNPs could be used as an internal reference. In a typical enzymatic reaction, ascorbic acid 2-phosphate is hydrolyzed by ALP to produce ascorbic acid. Therefore, the hybrid probe was shown to allow the ratiometric detection of ALP, with a linear range of 0.5-10UL-1 and a limit of detection (LOD) of 0.23UL-1. Finally, the proposed analytical strategy was successfully applied to detect ALP in human serum samples and to determine the concentration of an ALP inhibitor. Graphical Abstract.

Permanganate-Induced Efficient Mineralization of Poly(vinylidene fluoride) and Vinylidene-Fluoride Based Copolymers in Low-Temperature Subcritical Water

Reactions of poly(vinylidene fluoride) [PVDF], poly(vinylidene fluoride-co-hexafluoropropylene) [poly(VDF-co-HFP)] copolymer, and poly(vinylidene fluoride-co-perfluoromethyl vinyl ether) [poly(VDF-co-PMVE)] copolymer in subcritical water were performed with the aim to develop a technique for recycling fluorine element. By addition of KMnO₄ to the system, quasi-complete mineralization of PVDF was achieved at a rather low temperature (250 °C). When PVDF was reacted for 18 h in the presence of KMnO₄ (158 mM, corresponding to a 1.6-fold molar excess relative to both fluorine and carbon atom contents of PVDF), the fluoride ions (F–) yield reached 100%, and the amount of remaining total organic carbon decreased to 2% of the carbon atoms in the initial PVDF. Poly(VDF-co-HFP) and poly(VDF-co-HFP) copolymers also showed quasi-complete mineralizations under the same conditions. During the reactions, MnO₄– was modified into MnO₂. Compared to the previous method using H₂O₂, the reaction temperature that allows a complete mineralization was reduced by 50 °C.

A facile route to achieve ultrafine Fe2O3 nanorods anchored on graphene oxide for application in lithium-ion battery

Ultrafine Fe2O3 nanorods anchored on graphene oxide (GO) are synthesized by a one-pot route under mild conditions in presence of KMnO4 and Ni foam. Ni foam is beneficial for the formation of Fe2O3 rather than FeOOH under otherwise the same conditions, while KMnO4 accelerates the hydrolysis of FeCl3, which promotes the nucleation of Fe2O3 and the achievement of uniform ultra-small morphology thereby. As an anode material for lithium-ion batteries, the Fe2O3/GO manifests a reversible capacity of 1004 mA h g−1after 500 cycles at 200 mA g−1, and even presents a high reversible capacity of 722 mA h g−1 at 1600 mA g−1. The excellent electrochemical properties of Fe2O3/GO are attributed to the ultrafine nanorods of Fe2O3 and the strong interaction between Fe2O3 and GO, which can reduce the diffusion distance of Li+ ions, enlarge the electrode/electrolyte contact area and improve the cyclic stability of iron oxide.

Oxidative Deposition of Manganese Oxide Nanosheets on Nitrogen-Functionalized Carbon Nanotubes Applied in the Alkaline Oxygen Evolution Reaction.

The development of nonprecious catalysts for water splitting into hydrogen and oxygen is one of the major challenges to meet future sustainable fuel demand. Herein, thin layers of manganese oxide nanosheets supported on nitrogen-functionalized carbon nanotubes (NCNTs) were formed by the treatment of NCNTs dispersed in aqueous solutions of KMnO4 or CsMnO4 under reflux or under hydrothermal (HT) conditions and used as electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. The samples were characterized by X-ray photoelectron spectroscopy, X-ray diffraction, transmission electron microscopy, and Raman spectroscopy. Our results show that the NCNTs treated under reflux were covered by partly amorphous and birnessite-type manganese oxides, while predominantly crystalline birnessite manganese oxide was observed for the hydrothermally treated samples. The latter showed, depending on the temperature during synthesis, an electrocatalytically favorable reduction from birnessite-type MnO2 to γ-MnOOH. OER activity measurements revealed a decrease of the overpotential for the OER at a current density of 10 mA cm–2 from 1.70 VRHE for the bare NCNTs to 1.64 VRHE for the samples treated under reflux in the presence of KMnO4. The hydrothermally treated samples afforded the same current density at a lower potential of 1.60 VRHE and a Tafel slope of 75 mV dec–1, suggesting that the higher OER activity is due to γ-MnOOH formation. Oxidative deposition under reflux conditions using CsMnO4 along with mild HT treatment using KMnO4, and low manganese loadings in both cases, were identified as the most suitable synthetic routes to obtain highly active MnOx/NCNT catalysts for electrochemical water oxidation.

Template synthesis of hierarchical mesoporous δ-MnO2 hollow microspheres as electrode material for high-performance symmetric supercapacitor

The fabrication of graphene oxide (GO) thin layer encapsulated SiO2 microspheres (SiO2@GO) were accomplished by sonication-assisted interfacial self-assembly of tiny GO sheets on positively charged SiO2 microspheres. Then, hierarchical mesoporous δ-MnO2 hollow microspheres (δ-MnO2 HMS) were prepared by hydrothermal treatment of SiO2@GO microspheres in the presence of KMnO4, followed by removal of the SiO2 inner core in another hydrothermal reaction. The synthesized δ-MnO2 HMS was systematically characterized and found to exhibit remarkable supercapacitive performances in a three-electrode setup with the highest specific capacitance of 216.4 F g−1 at the current density of 0.5 A g−1, satisfactory rate capability and outstanding cyclic performance with the capacitance retention of 91.2% after consecutive charge/discharge at the current density of 5 A g−1 for over 3000 cycles. Such electrochemical behaviors of δ-MnO2 HMS electrode in a three-electrode system outperform those of a number of MnO2-based electrodes reported previously. Furthermore, a symmetric supercapacitor device of δ-MnO2 HMS//δ-MnO2 HMS was assembled. It released the maximum specific capacitance of 58.8 F g−1 at the current density of 0.25 A g−1, possessed excellent rate capability and favorable cycling stability with the capacitance retention up to 86.4% after cycling at the current density of 3 A g−1 for 3000 cycles, and offered the highest energy density of 8.2 W h kg−1 at a power density of 125 W kg−1, which was superior to that of many existing MnO2-based symmetric and asymmetric supercapacitors. The impressive electrochemical properties of δ-MnO2 HMS make it a promising candidate for constructing high-performance energy storage devices.

Resilient Energy Storage under High-Temperature with In-Situ-Synthesized MnOx@Graphene as Anode.

An novel exfoliation strategy to few-layered graphene (FLG) combined with in situ synthesized amorphous MnOx has been established via a facile and robust ball milling route in the presence of KMnO4. The facile synthesis approach has the features of low cost, environmentally friendly nature and scalable capability. As an anode for lithium-ion batteries, amorphous MnOx@FLG delivered a wonderful electrochemical performance under extremely operational conditions, that is, an excellent reversible capacity of 856 mAh g-1 at a high current density of 1 A g-1 after 75 cycles under a high temperature of 85 °C. Those excellent electrochemical performances could be ascribed to elaborately designed three-dimensional nanostructure, the well-chosen electrolyte, significant incorporation of in situ Mn(IV) nanocrystal and few-layered graphene, and the contribution of pseudocapacitance. Remarkable electrochemical performance under a widely operational temperature window makes the amorphous MnOx@FLG composites promising anode of Li-ion batteries for heavy-duty application.

Effects of Different Oxidants on HCl-based Pickling Process of 430 Stainless Steel

To shorten the time required for the pickling process and to enhance the quality of ferritic stainless steel plates, the effects of oxidants including hydrogen peroxide (H2O2), potassium permanganate (KMnO4), and potassium chlorate (KClO3) on the pickling behavior in HCl-based electrolyte as well as the surface quality of hot-rolled and blasted 430 stainless steel (430-SS) were studied. Experiments were conducted using mass-loss tests, microstructure analyses, potcntiodynamic polarization curves, and electrochemical impedance spectroscopy measurements. The results showed that the addition of oxidants substantially accelerated the pickling process of 430-SS by enhancing the cathodic reaction rate and reducing the charge transfer resistance. In electrolytes comprising 5 — 8 mass% HCl at a temperature of 40 — 60 °C and at the same concentration within the range from 0 to 2 mass%, H2O2 was demonstrated to be superior to KMnO4 and KClO3 in accelerating the pickling process. The surface quality of 430-SS pickled in the presence of H2O2 was better than those of specimens pickled in the presence of KMnO4 and KClO3 when the removal of the oxide layer, intergranular corrosion, and surface roughness were collectively considered. When 1 mass% H2O2 was added, the mass loss rate of 430-SS was increased by 629% and no residual oxide layer or intergranular corrosion was observed on the surface of the steel; in addition, the roughness was only 1. 7 μm. H2O2 was determined to be a better oxidant than KMnO4 and KCIO.3 when the pickling process, surface quality, solution recycling, and environment protection were considered as a whole.

The Toxicity of Graphene Oxides: Dependence on the Oxidative Methods Used

Graphene, a class of two-dimensional carbon nanomaterial, has attracted extensive interest in recent years, with a significant amount of research focusing on graphene oxides (GOs). They have been primed as potential candidates for biomedical applications such as cell labeling and drug delivery, thus the toxicity and behavior of graphene oxides in biological systems are fundamental issues that need urgent attention. The production of GO is generally achieved through a top-down route, which includes the usage of concentrated H₂SO₄ along with: 1) concentrated nitric acid and KClO₃ oxidant (Hoffmann); 2) fuming nitric acid and KClO₃ oxidant (Staudenmaier); 3) concentrated phosphoric acid with KMnO₄ (Tour); or 4) sodium nitrate for in-situ production of nitric acid in the presence of KMnO₄ (Hummers). It has been widely assumed that the properties of these four GOs produced by using the above different methods are roughly similar, so the methods have been used interchangeably. However, several studies have reported that the toxicity of graphene-related nanomaterials in biological systems may be influenced by their physiochemical properties, such as surface functional groups and structural defects. In addition, considering how GOs are increasingly used in the field of biomedicine, we are interested to see how the oxygen content/functional groups of GOs can impact their toxicological profiles. Since in-vitro testing is a common first step in assessing the health risks related with engineered nanomaterials, the cytotoxicity of the GOs prepared by the four different oxidative treatments was investigated by measuring the mitochondrial activity in adherent lung epithelial cells (A549) by using commercially available viability assays. The dose-response data was generated by using two assays, the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay and the water-soluble tetrazolium salt (WST-8). From the viability data, it is evident that there is a strong dose-dependent cytotoxic response resulting from the four GO nanomaterials tested after a 24 h exposure, and it is suggested that there is a correlation between the amounts of oxygen content/functional groups of GOs with their toxicological behavior towards the A549 cells.

Method for determining the number of aldehydes in dextran polyaldehyde using 2,4-dinitrophenylhydrazine

A method for determining the number of aldehydes in dextran polyaldehyde (DPA) was proposed. The method was based on the production of the DPAconjugate with 2,4-dinitrophenylhydrazine, reaction of which with base formed a colored product. The developed method for quantitative determination of aldehydes was distinguished from others by its simplicity and high sensitivity. Results of physicochemical studies of DPA and their derivatives were presented in order to identify their structures and formation mechanism in the presence of KMnO4.

One-step synthesis of PANI/Mn3O4 nanocomposites and evaluation of their electrochemical properties

In this paper, we have developed a simple, facile, and efficient approach to synthesize polyaniline/Mn3O4 (PANI/Mn3O4) nanocomposites using aniline as a reducer in the presence of KMnO4 without any additives or templates. The morphology of the composites is characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The results demonstrate that the tetrahedral Mn3O4 nanoparticles have uniform sizes and are finely dispersed in the PANI matrix. The crystallinity and chemical constituents of the composites are characterized by powder X-ray diffraction (XRD), Fourier transformation infrared spectroscopy (FTIR) and UV-vis spectrophotometry. Moreover, cyclic voltammetry (CV) measurements are used to characterize the electrochemical properties of PANI/Mn3O4 nanocomposites. The developed materials give a pair of redox peaks and have better operation stability, which indicates that the composites show distinct electrochemical performance. So the PANI/Mn3O4 nanocomposites would have potential applications in bioanalysis, biodetection and so on.