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Methane Conversions
Published in Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda, 1 Chemistry, 2022
Saeed Sahebdelfar, Maryam Takht Ravanchi, Ashok Kumar Nadda
Since the discovery of OCM reaction, a large number of metal oxides (simple and mixed oxides) have been tested for the reaction. A variety of metal oxides are effective in C–H bond activation. Non-reducible group IIA oxides showed the best catalytic performance in OCM. Alkali metal oxides, carbonates and some lanthanides forming sesquioxide ( M2O3 , such as La2O3 ) but not higher oxides (e.g., MO2 ) also showed good performances (Elkins and Hagelin-Weaver, 2013).
Air Pollution: Technology
Published in Brian D. Fath, Sven E. Jørgensen, Megan Cole, Managing Air Quality and Energy Systems, 2020
Heavy metals are bound to clay particles due to their ion-exchange capacity and to hydratized metal oxides, such as iron sesquioxide (As, Cr, Mo, P, Se, and V) and manganese sesquioxides (Co, Ba, Ni, and lanthanides). Calcium phosphate is further better able to bind As, Ba, Cd, and Pb in alkaline soil. Fulvic acids (molecular weight about 1000) and humic acid (molecular weight about 150,000) are able to form complexes with a number of heavy metals, Hg(II), Cu(II), Pb(II), and Sn(II). The mobility of heavy metals is dependent on a number of factors. The soil pore water contains soluble organic compounds (acetic acid, citric acid, oxalic acid, and other organic acids), partly excreted by the roots. These small organic molecules form chelated, soluble compounds with metal ions such as Al, Fe, and Cu. Activity of living organisms in soil may also enhance the mobility of heavy metal ions. Fungi and bacteria may utilize phosphate and thereby release cations. Formation of insoluble metal sulfide under anaerobic conditions from sulfate implies a reduced mobility. The lower oxidation stages of heavy metals are generally more soluble than the higher oxidation stages, implying increased mobility.
Characteristics of the Metal–Metal Oxide Reaction Matrix
Published in Anthony Peter Gordon Shaw, Thermitic Thermodynamics, 2020
The dioxides and trioxides of the group 6 metals are excellent oxidizers. Thermodynamically, the trioxides are more oxidizing than the dioxides. The chromium compounds CrO2 and CrO3 are more potent oxidizers than their molybdenum and tungsten homologues. Chromium trioxide is probably too reactive for use in practical pyrotechnic compositions. A safer way to access the +6 oxidation state is to use a chromate, toxicity concerns aside. Chromium also forms a sesquioxide, Cr2O3, in which the metal is present in the +3 oxidation state. This oxide has been used as a green pigment. It is not a strong oxidant, but it is reduced by fuels such as aluminum under the right conditions. The reaction of equation 2.25 is one way to manufacture chromium metal.
Production of M-type strontium hexaferrite magnetic powder with the high-pure magnetite concentrate via the ceramic process
Published in Journal of Asian Ceramic Societies, 2022
Yujuan Zhou, Tao Jiang, Bin Xu, Yuming Lin, Min Zhang, Lanming Liu, Shouguo Zhong, Chengzhi Wei, Yufeng Chen, Yongbin Yang, Qian Li
The ash black HPMC powder (Figure 1(a)) used in the study is from Chuanwei Group Mining Co., Ltd in Sichuan province, China. Table 1 illustrates the main chemical compositions of HPMC and its contents of total iron, silicon dioxide, and aluminum sesquioxide are 71.46%, 0.35%, and 0.23%, respectively. The iron content of ideal magnetite is 72.36% according to the chemical formula of Fe3O4, and the purity of HPMC in this study is calculated to be 98.8% based on the iron content. The XRD characterizes that the primary mineral in HPMC is magnetite as shown in Figure 1(b). Reagents like SrCO3, SiO2, H3BO3, CaCO3 and Al2O3 used here are all analytical grade.
Characteristics analysis of RuO2 in diesel: benthic-diatom Navicula sp. algae biodiesel in a CI engine
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Nitrogen oxides are usually produced due to this reacting the necessary oxygen and nitrogen under high-temperature conditions. Actually, NOx production is enhanced by enhancing the reaction temperature. Once the combustion flame temperature enhances and also the process is nearer to stoichiometric, the NOX emission increases, largely as a result of the increase of thermal NOX. The amount of NOx within the exhaust effluent flow is also based on engine design and working conditions. When oxide nano particles was utilized as additive, enormous droplets of fuel would have burnt more completely leaving less remainings in the combustion chamber. To another, incomplete combustion of fuel produces more emissions and additionally results in the formation of carbon deposit in the wall surfaces of the combustion chamber and on the other parts like valves. The variation of NOX with regards to load has been presented in Figure 10. It is concluded that the combustion of B20 lower the NOX than the B20 with RuO2. Eq. (3) shows the process of oxygen adsorption by Ruthenium Sesquioxide (Ru2O3) which breaks NOx into simple nitrogen (Mehta, Chakraborty, and Parikh 2014).
Municipal solid waste incineration (MSWI) fly ash washing pretreatment by biochemical effluent of landfill leachate: a potential substitute for water
Published in Environmental Technology, 2018
Yunfeng Xu, Yu Fu, Wei Xia, Dan Zhang, Da An, Guangren Qian
The concentrations of metal ions were determined by using an atomic emission spectrometry system equipped with inductively coupled plasma (ICP-AES, Prodidy; Lee-man Co.). Total organic carbon (TOC) and total nitrogen (TN) were measured by Multi N/C 2100 (Analytik Jena AG, Germany). Platinum (Pt), cobalt oxide or chromium sesquioxide was used as the catalyst. Fly ash pH was measured by preparing a 1:2.5 ratio of fly ash to deionized water and using a pH meter (PHS-3C) with a glass electrode (Model CL 51), and the pH of BEL was directly measured by a pH meter. The concentrations of Cl−, nitrite (), nitrate () and ions in BEL were determined by ion chromatography (Metrohm). Chemical composition of raw fly ash was measured by XRF (XRF-1800; Shimadzu). FTIR spectroscopic techniques were used to identify the functional groups of samples collected from washing pretreatment. FTIR spectra of the samples were obtained by FTIR 380 of Thermo Fisher Scientific using the KBr pellet method.