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Traditional use of biochar
Published in Johannes Lehmann, Stephen Joseph, Biochar for Environmental Management, 2015
13C NMR spectroscopy further revealed a signal corresponding to aromatic acids such as mellitic acid in soils from Thailand (Möller et al, 2000), considered to be a metabolite of biochar oxidation (Glaser et al, 1998, 2001). Thus, slow biochar oxidation over time produced carboxylic groups on the edges of the aromatic backbone or aromatic acids as metabolites (Glaser et al, 2000; Liang et al, 2006), increasing the capacity of ionic binding and, thus, of reducing nutrient leaching (Lehmann et al, 2003). From these results it can be concluded that biochar found in Terra Preta is not only responsible for the long-term C sequestration, but is also a key factor for the high fertility of Terra Preta (Glaser et al, 2003; Glaser, 2007).
Synthesis of Graphene Nanosheets
Published in Ling Bing Kong, Carbon Nanomaterials Based on Graphene Nanosheets, 2017
Ling Bing Kong, Freddy Boey, Yizhong Huang, Zhichuan Jason Xu, Kun Zhou, Sean Li, Wenxiu Que, Hui Huang, Tianshu Zhang
A typical process of Hummers’ method is described as follows [6]. 100 g of flake graphite powder and 50 g of sodium nitrate were mixed in 2.3 liters of sulfuric acid. The mixing was carried out in a container had been cooled to 0°C in an ice-bath for the purpose of safety. While maintaining vigorous agitation, 300 g of potassium permanganate was added to the suspension. The rate of addition was controlled carefully to prevent the temperature of the suspension from exceeding 20°C. The ice-bath was then removed and the temperature of the suspension was increased to 35 ± 3°C, where it was maintained for 30 min. As the reaction progressed, the mixture gradually thickened with a diminishing in effervescence. At the end of 20 min, the mixture became pasty with the evolution of only a small amount of gas. The paste was brownish-gray in color. At the end of 30 min, 4.6 liters of water were slowly stirred into the paste, causing violent effervescence and an increase in temperature to 98°C. The diluted suspension, brown in color, was maintained at this temperature for 15 min. The suspension was then further diluted to about 14 liters with warm water and treated with 3% hydrogen peroxide to reduce the residual permanganate and manganese dioxide to colorless soluble manganese sulfate. Upon treatment with the peroxide, the suspension turned bright yellow. The suspension was then filtered, resulting in a yellow-brown filter cake. The filtering was conducted while the suspension was still warm in order to avoid precipitation of the slightly soluble salt of mellitic acid formed as a side reaction. After washing the yellowish-brown filter cake three times with a total of 14 liters of warm water, the graphitic oxide residue was dispersed in 32 liters of water to 0.5% solids. The remaining salt impurities were removed by treating with resinous anion and cation exchangers. The dry form of graphitic oxide was obtained by using centrifugation, followed by dehydration at 40°C over phosphorus pentoxide. This method has been widely used in the open literature.
Physical Constants of Organic Compounds
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
C8H6O2 C8H8N2O2 C8H8N2O2 C20H30O6 C14H18O6 C14H14O4 C14H18O4 C8H12N2 C8H10O2 C8H10O2 C8H10O2 C10H10O4 C10H10O4 C13H10O3 C6H6O6S2 C6H4Cl2O4S2 C6H6S2 C6H6S2 C8H11N C8H12ClN Phenethyl alcohol Mellitic acid C8H10O C12H6O12 C7H10ClN C7H7ClO2S C7H7FO2S Thiobenzyl alcohol C7H8S
Production of benzenepolycarboxylic acids by oxidation of pre-pyrolyzed Shengli lignite
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2018
Wei-Jia Jiang, Yu-Gao Wang, Ze-Shi Niu, Jun Shen
SL and its pyrolyzed residues were subjected to mild oxidation under the same condition. As Figure 3 displays, the oxidation weightlessness rate decreased from SL to PR550, which implied that the pyrolysis of coal would lower its oxidation reactivity. However, as exhibited in Figure 3, different from the oxidation reactivity of pyrolyzed residues, the yields of BPCAs increased from SL to PR250, then slightly decreased for PR350, and dramatically dropped from PR350 to PR550. As displayed in Table 3, 11 BPCAs were qualitatively and quantitatively analyzed by HPLC. The yield of mellitic acid varied as the one of BPCAs from the oxidation of SL to PR550 except for PR350. The production of mellitic acid reached its top; meanwhile, its selectivity was the highest for PR350, which would facilitate the further separation of mellitic acid, as shown in Figure 4. The fact suggested that proper pyrolysis treatment would contribute to the production of mellitic acid.