A concise and mild green synthetic route of sodium chromate through ferrochrome electrochemical oxidation and in-situ purification.

Title A concise and mild green synthetic route of sodium chromate through ferrochrome electrochemical oxidation and in-situ purification.
Authors B. Li; P. Han; B. Zhang; H. Feng; W. Li; Y. Dong
Journal J Hazard Mater
DOI 10.1016/j.jhazmat.2019.121699
Abstract

Sodium chromate (NaCrO) is the main semi-finished product for manufacturing all other chromium compounds with wide industrial applications. Unfortunately, the traditional processes for producing NaCrO generate amounts of solid and liquid waste that pose serious threats to the environment and human health. Here, a green and convenient synthesis process for NaCrO was developed by electrochemical oxidation of high carbon ferrochromium in sodium hydroxide aqueous solution at room temperature and atmosphere pressure. Through electrochemical oxidation process, NaCrO was obtained from electrolyte conveniently. Furthermore, the prepared NaCrO electrolyte was purified efficiently in-situ to remove water-soluble carbon and iron compound through one pot hydrothermal progress at 260 ? for 6?h. After the hydrothermal progress the water-soluble carbon particles were oxidized to NaCO by NaCrO while some chromium (III) compound microspheres possessing hierarchical microstructure was obtained. In the meantime, iron compound was adsorbed on the surface of chromium (III) compound microspheres. And the removal rate of iron compound was more than 99.9 %. The main factors influencing the electrochemical oxidation process were investigated including sodium hydroxide concentrations, reaction temperatures and current intensities. The new process is a promising cleaner approach for chromium compound industrial productions which prevent chromium pollution from the source.

Citation B. Li; P. Han; B. Zhang; H. Feng; W. Li; Y. Dong.A concise and mild green synthetic route of sodium chromate through ferrochrome electrochemical oxidation and in-situ purification.. J Hazard Mater. 2020;387:121699. doi:10.1016/j.jhazmat.2019.121699

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Chromium

See more Chromium products. Chromium (atomic symbol: Cr, atomic number: 24) is a Block D, Group 6, Period 4 element with an atomic weight of 51.9961. Chromium Bohr ModelThe number of electrons in each of Chromium's shells is 2, 8, 13, 1 and its electron configuration is [Ar] 3d5 4s1. Louis Nicolas Vauquelin first discovered chromium in 1797 and first isolated it the following year. The chromium atom has a radius of 128 pm and a Van der Waals radius of 189 pm. In its elemental form, chromium has a lustrous steel-gray appearance. Elemental ChromiumChromium is the hardest metallic element in the periodic table and the only element that exhibits antiferromagnetic ordering at room temperature, above which it transforms into a paramagnetic solid. The most common source of chromium is chromite ore (FeCr2O4). Due to its various colorful compounds, Chromium was named after the Greek word 'chroma.' meaning color.

Sodium

Sodium Bohr ModelSee more Sodium products. Sodium (atomic symbol: Na, atomic number: 11) is a Block D, Group 5, Period 4 element with an atomic weight of 22.989769. The number of electrons in each of Sodium's shells is [2, 8, 1] and its electron configuration is [Ne] 3s1. The sodium atom has a radius of 185.8 pm and a Van der Waals radius of 227 pm. Sodium was discovered and first isolated by Sir Humphrey Davy in 1807. In its elemental form, sodium has a silvery-white metallic appearance. It is the sixth most abundant element, making up 2.6 % of the earth's crust. Sodium does not occur in nature as a free element and must be extracted from its compounds (e.g., feldspars, sodalite, and rock salt). The name Sodium is thought to come from the Arabic word suda, meaning "headache" (due to sodium carbonate's headache-alleviating properties), and its elemental symbol Na comes from natrium, its Latin name.

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