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Storage of Fluctuating Renewable Energy
Published in Subhas K. Sikdar, Frank Princiotta, Advances in Carbon Management Technologies, 2021
The comparison of the numbers explains why the Li-ion battery is selected for the electric cars. The partner of the Li in the cathode can be Cobalt Oxide (or Lithium Cobaltate), Manganese Oxide (or Lithium Manganate), Iron Phosphate, Nickel Manganese Cobalt (or NMC) and Nickel Cobalt Aluminum Oxide (or NCA).
Oxidation Reactions
Published in Michael B. Smith, A Q&A Approach to Organic Chemistry, 2020
For an acyclic alkene, cis- addition of the hydroxyl groups applies, but the terms cis- and trans- do not apply to the diol product. To sort out the stereochemistry of the product, first rotate the alkene as shown in A, such that one ethyl group is projected to the front of the page and one ethyl group is projected to the rear, reflecting the trans- geometry. If permanganate reacts from the bottom face of the alkene as it is drawn manganate ester B is formed, with the (3R,4R) stereochemistry. If permanganate reacts from the top face, manganate ester C is formed, with the (3S,4S) stereochemistry. Structures B and C are enantiomers of a single diastereomer. When these manganate esters react with hydroxide, the stereochemistry at carbon is retained since hydroxide attacks manganese rather than carbon. The final products are (3R,4R)-hexanediol and (3S,4S)-hexanediol, in equal amounts. The cis- addition has led to a single diastereomer, but it is racemic, reflecting the fact that the planar alkene can be attacked from two opposite faces. Why does the conversion of an alkene to the corresponding 1,2-diol use relatively low temperatures and dilute solutions of permanganate?
Ozone For Drinking Water Treatment – Evolution And Present Status
Published in Rip G. Rice, Safe Drinking Water, 2017
Permanganate is toxic, and must be prevented from entering water distribution networks, where it is slowly reduced to insoluble MnO2, leading to buildup of manganate scales. To avoid this possibility, ozonation for oxidation of iron and/or manganese normally is conducted prior to filtration, at an early stage in the water treatment process. Holding the ozonized water 30 minutes allows traces of permanganate to oxidize some of the organics present, and be reduced to the insoluble tetravalent state:
Biopolymer composites: a review
Published in International Journal of Biobased Plastics, 2021
Basheer Aaliya, Kappat Valiyapeediyekkal Sunooj, Maximilian Lackner
Acrylation uses acrylic acid to improve the interfacial bonding between the fiber and matrix. Acrylic acid reacts with the cellulosic OH groups of the fiber and provides more access of reactive cellulose macro-radicals to the polymerization medium. The carboxylic acids from coupling agents form ester linkages with cellulosic OH groups, and reduces hydrophilic OH groups from the fiber and promote moisture resistance properties [35]. For fiber surface modification, isocyanate works as a coupling agent. The functional group of isocyanate reacts with OH groups of cellulose and lignin in fiber, and forms a urethane linkage. The linkage imparts strong covalent bonds between fiber and matrix [35]. Stearic acid in ethyl alcohol solution is used for the modification of fiber surface. The carboxyl group of stearic acid reacts with the hydrophilic OH groups of the fiber and enhances moisture resistance. The treatment removes non-crystalline constituents from fiber, which leads to the breakdown of fiber bundles and fibrillation occurs. Fiber dispersion into the matrix facilitates better bonding at the interfacial region and improves composite properties [35]. Permanganate treatment on natural fibers is done by using potassium permanganate (KMnO4) in acetone solution. The treatment produces highly reactive permanganate ions that react with the cellulose OH groups and forms cellulose-manganate for initiating graft copolymerization. This improves the chemical interlocking at the interfacial region and increase the adhesion with matrix [35]. The treatment of fibers with potassium permanganate also removed impurities and waxes from fiber surface and improved its physico-chemical properties [59].
Effect of soft template variation on the synthesis, physical, and electrochemical properties of Mn3O4 nanomaterial
Published in Inorganic and Nano-Metal Chemistry, 2020
Muhammad Danish, Muhammad Tayyab, Arusa Akhtar, Ataf Ali Altaf, Samia Kausar, Shafiq Ullah, Muhammad Iqbal
Nowadays, high-performance electrical energy storage materials are required in batteries, power electronics, and electrical vehicles.[1] Different materials, such as lithium manganate, conducting polymers, carbon nanotubes, metal oxides, transition metal-doped lithium manganese oxides, co-doped TiO2, and transition elements, are used for the electrodes of batteries and capacitors.[2]
Evolution of a self-assembled chessboard nanostructure spinel in a CoFeGaMnZn multicomponent oxide
Published in Philosophical Magazine, 2022
Avnish Singh Pal, Aman Kumar Lal Das, Ankit Singh, Kevin M. Knowles, Md. Imteyaz Ahmad, Joysurya Basu
Powder XRD patterns from the sintered and aged pellets of CoFeMn, ZnGaMn and CoFeGaMnZn oxides are shown in Figure 1. The pattern from CoFeMn oxide can be indexed in terms of two spinel phases: CoFe2O4 (JCPDS card No. 00-022-1086) (space group with a ≈ 8.3 Å [18]) and CoMn2O4 (JCPDS card no. 00-001-1126) ( with a = 5.72 Å and c = 9.27 Å), which have the cubic inverse spinel structure with a cubic F (FCC: Face centred cubic) Bravais lattice and a tetragonal I (BCT: Body centred tetragonal) spinel structure, respectively [21]. This indexing is not unique because there is a possibility that the phase(s) in the CoFeMn oxide pellet have mixed chemistries, altering subtly the nature of the phases present and their lattice parameters [19]. Similarly, the ZnGaMn oxide powder after sintering and ageing can be indexed in terms of two spinel phases: ZnGa2O4 (JCPDS card no. 00-038-1240) ( with a = 8.33 Å [19]) and ZnMn2O4 (JCPDS card no. 00-024-1133) (with a = 5.66 Å and c = 9.34 Å [21]), also with crystal structures with cubic F and tetragonal I Bravais lattices respectively. Here too, the indexing is not unique because of the possibility that the mixed chemistries within the pellet changes the nature of the phase(s) present and their lattice parameters [20]. The quinary CoFeGaMnZn oxide also produces an XRD pattern similar to those from CoFeMn oxide and ZnGaMn oxide. The diffraction peaks match quite closely those attributed to CoFe2O4, CoMn2O4, ZnMn2O4 and ZnGa2O4. The crystal structures of transition element-based spinel phases are sensitive to the cationic ratio, heat treatment temperature and cooling rate. In the case of manganate spinels, those with high manganese content tend to form tetragonal phases, while those with low manganese content tend to form cubic spinel phases at room temperature. Heat treatment temperatures and cooling rates also alters the cationic distribution in the interstitial sites that in turn can change the crystal symmetry [21]. However, the X-ray diffraction peaks are often quite broad, apart from the 111 and 222 peaks. This broadening of the peaks suggests that the microstructure is on a fine scale and that there may be a number of spinel phases present. The possibility of strain as an origin of the peak broadening is unlikely because the pellets were aged for a significantly long period of time. Some spinel peaks in the quinary oxide powder are shifted from the originally reported spinels: this might indicate the formation of novel mixed spinel phase(s) in the quinary oxide. In summary, it is evident that the X-ray diffraction information from the multicomponent oxide is difficult to deconvolute with confidence into individual spinel phases; this is why TEM is required in conjunction with X-ray diffraction for phase identification.