Sodium sulfite

About: Sodium sulfite is a research topic. Over the lifetime, 2548 publications have been published within this topic receiving 18523 citations. The topic is also known as: Na2SO3 & Anhydrous sodium sulfite.

Production of Water-Soluble Hardwood Kraft Lignin via Sulfomethylation Using Formaldehyde and Sodium Sulfite

Abstract: Kraft lignin can be extracted from black liquor (i.e., spent liquor) of a kraft pulping process to produce value-added chemicals, but its limited water solubility hampers its end-use applications. The main objective of this study was to investigate the sulfomethylation of kraft lignin to produce water-soluble kraft lignin with an anionic charge density. In this work, hardwood kraft lignin was modified with formaldehyde and sodium sulfite under alkali conditions. The optimum conditions for sulfomethylation were 0.5 M NaOH(aq), 0.9 mol/mol sodium hydroxymethyl sulfonate/lignin at 100 °C for 3 h, and 20 g/L lignin concentration. The resulting lignin had a charge density of −1.60 mequiv/g and sulfonate group content of 1.48 mmol/g. The molecular weight, structure, thermal behavior, and elemental analyses of the product were also assessed. The modified lignin was used as a cement dispersant, and the dispersibility of cement was increased from 60 to 155 mm by adding 1.2 wt % of sulfomethylated lignin to cement....

Absorption of NOx gases

Abstract: Oxidation of nitric oxide is an important step in NOx absorption. Recent advances namely catalytic oxidation and the use of slrong oxidizing agents have been reviewed. The refinements which have been made in the kinetics of NO oxidation have been discussed. Several liquid phase absorbents have been suggested for the NO removal, particularly for the purpose of pollution abatement. Different models for NO oxidation using nitric acid have been analysed and the limitations of published information have been brought out. Absorption of tetravalent nitrogen oxide (NO2 and N2O4) has received considerable attention. The absorbents include water, nitric and sulfuric acids, sodium hydroxide, sodium sulfite and sodium chlorite. Absorption in water and nitric acid is important in the manufacture of nitric acid. The published information on the mechanism of NO2 and N2O4 absorption in water has been critically analysed. The problem of nitrous acid decomposition has been analysed on the basis of film theory. The predicti...

Reduction of Inorganic Substances by Yeasts. I. Extracellular Reduction of Sulfite by Species of Candida.

Abstract: of reducing substances formed by the cells during glucose metabolism.1*2 We have previously reported the presence in baker's yeast and in Candida albicans of systems utilizing reduced coenzyme II as hydrogen donor for the reduction of oxidized glutathione by glutathione reductase,3,4 and transferring hydrogen from reduced coenzyme I to cystine in the presence of its reductase.5 This paper describes sulfite reduction by yeasts with special reference to the pronounced abilities of some species of Candida to reduce inorganic sulfite when it is supplied as a bismuth complex in appropriate mediums. Certain species of

Extrusion of feather keratin

Abstract: Keratin obtained from poultry feathers was extruded at 120°C using a combination of glycerol, water, and sodium sulfite as processing aids. Rheological proper- ties were assessed as a function of water, glycerol, and sodium sulfite content as well as extruder die temperature. The lowest viscosity blends at a constant feather keratin concentration of 60 wt % were found at glycerol concentra- tions that were higher than the water concentration and sodium sulfite concentrations of 3- 4 wt % of the feather keratin fraction. For the melt state, higher or lower sodium sulfite concentrations resulted in increased viscosity. In the solid state, it was observed that processing induced orien- tation increased the tensile properties of the extrudates. Raman spectroscopy and DSC showed that there was a transition from -helix to -sheet at sodium sulfite concen- trations of less than 4 wt %. At greater sodium sulfite con- centration, increased crystallinity was found, because kera- tin chains could be extended more during processing. © 2006 Wiley Periodicals, Inc.* J Appl Polym Sci 100: 1432-1442, 2006

Adsorption and reaction of sulfur dioxide on alumina and sodium-impregnated alumina

Abstract: The adsorption and oxidation of SO2 on alumina and sodium-impregnated alumina has been examined using thermogravimetric analysis and diffuse reflectance infrared Fourier transform spectroscopy. Sulfur dioxide chemisorbs initially at basic sites to form an adsorbed sulfite, which is quantitatively converted to sulfate on oxidation. It has been observed that at low coverages, ∼2.6 μmol/m2, sodium acts as a promoter for the formation of an adsorbed sulfite and sulfate which have structures similar to those of aluminum sulfite and sulfate, respectively. At higher sodium loadings, a second type of adsorbed SO2 is formed, similar to sodium sulfite and sulfate. The species with the aluminum sulfate structure appears to be more easily decomposed than does the sodium sulfate species and accounts for the regenerable adsorption capacity. Formation of the sodium sulfate species appears to account for the loss of adsorption capacity as the number of adsorption/regeneration cycles increases. Oxidation of the sulfite fo...