Topic
Oxalic acid
About: Oxalic acid is a research topic. Over the lifetime, 11584 publications have been published within this topic receiving 173263 citations. The topic is also known as: ethanedioic acid & H2ox.
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TL;DR: In this article, a post-treated ZSM-5 zeolite was post-treated by desilication with sodium hydroxide, dealumination with oxalic acid, or both of them in a sequential way to fine tune the zeolate catalysts with hierarchically porous structure.
159 citations
TL;DR: In this paper, the photoelectro-fenton reaction was applied to 2,4,5-trichlorophenoxyacetic acid (2,4-5-T) in an undivided cell with a Pt anode and an O 2 -diffusion cathode under UV irradiation, and its great oxidative ability is due to the fast reaction of organics with the high concentration of oxidizing hydroxyl radicals produced in the medium from Fenton's reaction between added Fe 2+ and H 2 O 2 electrogenerated by the cathode
159 citations
TL;DR: Different activated carbon-supported Fe catalysts have been prepared and tested in CWPO of phenol and three well characterized activated carbons and two iron precursors (iron nitrate and iron pentacarbonyl) have been used as discussed by the authors.
Abstract: Different activated carbon-supported Fe catalysts have been prepared and tested in CWPO of phenol Three well characterized activated carbons and two iron precursors (iron nitrate and iron pentacarbonyl) have been used The behavior of these catalysts in CWPO has been related with their porous structure, surface composition, in terms of oxygen groups and Fe distribution onto the catalyst particles The catalysts with a more uniform distribution of Fe showed a higher oxidation activity than the ones with an internal (egg-yolk type) or external (egg-shell type) distribution These last provoke a faster decomposition of H 2 O 2 mainly to O 2 , non-reactive at the mild reaction temperature used (50 °C) No significant differences were observed from the iron precursors Complete conversion of phenol and almost 80% mineralization were obtained in less than 2 h with the best catalyst The residual by-products consisted in short-chain organic acids without significance in terms of toxicity Fe leaching was observed in all the cases which can be mainly attributed to the presence of oxalic acid as oxidation by-product, refractory to the CWPO process investigated The intensity of Fe leaching was related with the concentration of oxalic acid
158 citations
TL;DR: In this paper, the major impurities in the clay are quartz and siderite, which can be removed at room temperature by using 0.4 M oxalic acid solution, and the iron content of the clay may be reduced further by treating with wet high intensity magnetic separator (WHIMS) or leaching with organic acids.
158 citations
TL;DR: Oxalate accumulation was induced in Aspergillus niger by shifting the pH from 6 to 8.1, indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate, and this enzyme is located in the cytoplasm of A. niger.
Abstract: Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of Pi and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14CO2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this was oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle.
158 citations