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.

Sodium-limestone double alkali flue gas desulfurization process with improved limestone utilization

Abstract: A method for improving utilization of limestone in a sodium-limestone double alkali flue gas desulfuriza­tion process. Spent alkaline absorber solution, con­taining sodium sulfite and sodium bisulfite, is diverted for regeneration treatment in a series of stirred tank reactors, where it is contacted with the limestone regenerating agent. Dilute slurry from the last reactor is concentrated in a thickener, and the concentrated underflow slurry from the thickener is then treated further in an after-reactor circuit. Since the thickener underflow slurry contains residual unreacted limestone, the slurry is contacted with a side stream of spent alkaline absorber solution in the after-reactor circuit to promote further reaction of residual limestone before the solids are separated and discarded.

Reversible 'konjak' and food additive composed thereof

Abstract: PURPOSE:To obtain a reversible KONJAK (paste made from the starch of devil's tongue) which is liquid or pasty at normal temperature and is coagulated to the state of KONJAK under elevated temperature, by adding a specific compound as a catalyst to a tuberous root of devil's tongue or water-containing KONJAK powder and heat-treating the mixture. CONSTITUTION:A tuberous root of devil's tongue or water-containing KONJAK powder is added with one or more compounds selected from sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium carbonate, sodium sulfite, magnesium carbonate, sodium bicarbonate, ammonium bicarbonate and ammonium carbonate at a rate to give a mixture having a pH of <=10. The obtained mixture is heat-treated at 70-130 deg.C. Refined KONJAK powder is better than the tuberous root as the KONJAK raw material because of the stabilized properties of the powder. The amount of the above compound to be added as a catalyst is preferably determined by a preliminary experiment using a small amount of the KONJAK powder.

Comparative study of the biochemical properties of membrane-bound and soluble polyphenol oxidase from Prunus mume

Abstract: Browning occurs during fruit and vegetable processing mainly as a result of oxidation by polyphenol oxidases. We compared the biochemical properties of membrane-bound polyphenol oxidase (mPPO) and soluble polyphenol oxidase (sPPO) isolated and purified from Prunus mume. The sPPO showed a greater affinity for the substrate catechol. The highest activity of sPPO was catechol, while those of the mPPO were catechol and 4-methylcatechol. The optimum pH of sPPO was 5.0, while that of the mPPO were 4.5 and 5.5; the optimum temperatures of sPPO and mPPO were 40 °C and 60 °C, respectively; and the sPPO was more resistant to acidic environments, while the mPPO maintained better stability within temperature changes. The metal ions Mg2+ and Na+ were able to activate both sPPO and mPPO of P. mume, while Al3+ and K+ significantly inhibited their activities, and both Cu2+ and Ca2+ inhibited the activity of sPPO but activated that of mPPO. Different inhibitors were found to have different effects on sPPO and mPPO, however, sodium sulfite, sodium bisulfite, l-cysteine, glutathione and ascorbic acid had obvious inhibitory effects on both forms of polyphenol oxidase. Provide theoretical support for the research on the characteristics and browning mechanism of polyphenol oxidase in fruits and vegetables.

Enhancing Enzyme-Mediated Cellulose Hydrolysis by Incorporating Acid Groups Onto the Lignin During Biomass Pretreatment.

Abstract: Lignin is known to limit the enzyme-mediated hydrolysis of biomass by both restricting substrate swelling and binding to the enzymes. Pretreated mechanical pulp (MP) made from Aspen wood chips was incubated with either 16% sodium sulfite or 32% sodium percarbonate to try to incorporate similar amounts of sulfonic and carboxylic acid groups onto the lignin (60mmol/kg substrate) present in the pulp without resulting in significant delignification. When Simon’s stain was used to assess potential enzyme accessibility to the cellulose, it was apparent that both post-treatments enhanced accessibility and cellulose hydrolysis. To try to further elucidate how acid group addition might influence potential enzyme binding to lignin, Protease Treated Lignin (PTL) was isolated from the original and modified mechanical pulps and added to a cellulose rich, delignified Kraft pulp. As anticipated, the PTLs from both the oxidized and sulfonated substrates proved less inhibitory and adsorbed less enzymes than did the PTL derived from the original pulp. Subsequent analyses indicated that both the sulfonated and oxidized lignin samples contained less phenolic hydroxyl groups, resulting in enhanced hydrophilicity and a more negative charge which decreased the non-productive binding of the cellulase enzymes to the lignin.

Process for producing anhydrous sodium sulfite using smelting smoke

Abstract: The present invention relates to sodium hydroxide absorption process of utilizing sodium hydroxide in absorbing low density smelting fume to produce anhydrous sodium sulfite. The present invention features that in the absorption tower, fume containing SO2 after being purified is made to countercurrent contact with sodium hydroxide solution to absorb SO2 to pH 5-6, sodium hydroxide is added to regulate pH to 9-10, sodium sulfate solution is added to eliminate iron, and through further filtering in filtering machine, solid-liquid separation and concentration, coarse sodium sulfite product of 42-45 % concentration is obtained, and the anhydrous sodium sulfite product is produced through further hot air contact drying and dewatering. The present invention reduces environmental pollution while producing stable sodium sulfite product.