Showing papers on "Sodium sulfite published in 1991"

Relationship between hydrogen consumption, dehalogenation, and the reduction of sulfur oxyanions by Desulfomonile tiedjei.

Abstract: Resting-cell suspensions of Desulfomonile tiedjei consumed H2 with 3-chloro-, 3-bromo-, and 3-iodobenzoate as electron acceptors with rates of 0.50, 0.44, and 0.04 mumol h-1 mg-1, respectively. However, benzoate and 3-fluorobenzoate were not metabolized by this bacterium. In addition, H2 uptake was at least fourfold faster when sulfate, sulfite, or thiosulfate was available as the electron acceptor instead of a haloaromatic substrate. When sulfite and 3-chlorobenzoate were both available for this purpose, the rate of H2 uptake by D. tiedjei was intermediate between that obtained with either electron acceptor alone. Hydrogen concentrations were reduced to comparably low levels when either 3-chlorobenzoate, sulfate, or sulfite was available as an electron acceptor, but significantly less H2 depletion was evident with benzoate or nitrate. Rates of 3-chlorobenzoate dechlorination increased from an endogenous rate of 14.5 to 17.1, 74.0, 81.1, and 82.3 nmol h-1 mg-1 with acetate, pyruvate, H2, and formate, respectively, as the electron donors. Sulfite and thiosulfate inhibited dehalogenation, but sulfate and NaCl had no effect. Dehalogenation and H2 metabolism were also inhibited by acetylene, molybdate, selenate, and metronidazole. Sulfite reduction and dehalogenation were inhibited by the same respiratory inhibitors. These results suggest that the reduction of sulfite and dehalogenation may share part of the same electron transport chain. The kinetics of H2 consumption and the direct inhibition of dehalogenation by sulfite and thiosulfate in D. tiedjei cells clearly indicate that the reduction of sulfur oxyanions is favored over aryl dehalogenation for the removal of reducing equivalents under anaerobic conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Silver halide photographic sensitive material

Abstract: PURPOSE:To stably obtain an action of hardening gelatin and photographic characteristics by incorporating at least one kind of alkaline agent in an aldehyde type hardener CONSTITUTION:At least one kind of alkaline agent is incorporated in the aldehyde type hardener contained in at least one of hydrophilic colloidal layer of the photographic sensitive material formed on a support As this alkaline agent to be used for the hardener stabilizer, usually used alkalis, that is, aqueous solutions of alkali metal and ammonium hydroxides and salts, such as sodium or potassium hydroxide, sodium or potassium carbonate, sodium sulfate or sodium sulfite, ammonium carbonate sodium phosphate, are used, and they are not especially limited, so long as it is alkaline, thus permitting the gelatin hardening action and the photographic characteristics to be both stably maintained

Electrochemical oxidation of sulphite ions at graphite electrodes

Abstract: The electrochemical oxidation of sodium sulphite has been studied in aqueous sodium sulphate solution at two different graphite electrodes, one being of natural graphite (EC) and the other impregnated with phenol (ECK). The objective of the present work was to obtain some insight into the direct oxidation as well as the indirect oxidation, via produced oxygen radical species, of sulphite on non-metal electrodes. For this reason a study of the oxidation of sulphite in the concentration range between 0–0.10m in aqueous sodium sulphate using a batch electrochemical reactor, operating potentiostatically, was undertaken. The potential range was chosen between 1.0 to 2.5 V/SCE, and the concentration of the supporting electrolyte, sodium sulphate, was kept constant at 0.5m. A kinetic Tafel type law, considering irreversible behaviour for the direct sulphite oxidation and the mass transfer performance in regards to the experimental conditions were applied to predict the time variations of the sulphite conversion.

Electrochemical Behavior of Electroless Gold Plating with Ascorbic Acid as a Reducing Agent

Abstract: A novel electroless (autocatalytic) gold plating bath containing sodium L-ascorbate as the reducing agent has been developed. A suitable bath composition was formulated based on the results of an electrochemical study in which were determined at a gold electrode the anodic polarization curves of various reducing agents and the cathodic polarization curves of sodium tetrachloroaurate (III) dissolved in solutions of sodium sulfite and/or sodium thiosulfate.A typical bath containing 0.0125mol/dm3 sodium tetrachloroaurate (III), 0.1mol/dm3 sodium sulfite, 0.1 mol/dm3 sodium thiosulfate, and 0.25mol/dm3 sodium L-ascorbate, was operated under moderate conditions, typically at a pH of 6.0 and 333K. The rate of gold deposition obtained with this bath was in the same range or greater than that obtained with the classical cyanide-borohydride bath. The deposition rate of the new bath depended on both the ascorbate and gold concentrations, and the gravimetrically determined deposition rate was found to correspond well with the rate estimated from electrochemical polarization measurements.

Detoxification of aflatoxin B1 by different chemical methods and evaluation of the effectiveness of the treatments applied

Abstract: Different chemical treatments were applied to solutions of Aflatoxin B1 in order to compare their efficacy for the detoxification of AfB1: sodium sulfite, sodium hydrogen sulfate, sodium hydroxide, ammonia, sodium hypochlorite, hydrogen peroxide. The rate of the detoxification of AfB1 has been followed by three experimental approaches: 1. Quantitative estimation of the unmodified AfB1 by HPLC chromatography. 2. Quantitative estimation of the most toxic metabolite. AfB1-epoxide by chemical transformation into the trishydroxy AfB1 derivative followed by HPLC analysis. 3. Determination of the bacterial mutagenic activity, following the Ames' test. Among the different detoxification methods that were compared, the treatment with sodium sulfite proved to be the most efficient and seems thus to be recommended for foods contaminated by AfB1.

A Practical Synthesis of Arylthiocyanates from Arenesulfinates or Arenesulfonyl Chlorides with Cyanotrimethylsilane

Abstract: Preparation of arylthiocyanates by simply mixing aromatic sulfinates with cyanotrimethylsilane (TMSCN) was achieved in good to moderate yields. The thiocyanates were also obtained directly from sulfonyl chloride using TMSCN, sodium sulfite, and potassium carbonate.

Uncatalyzed oxidation of aqueous sodium sulfite and its ability to simulate bacterial respiration

Abstract: Kinetics of the uncatalyzed oxidation of sodium sulfite in dilute, aqueous solution is investigated by measuring oxygen transfer rates to both well-stirred and quiescent pools of solution under pseudo-steady-state conditions with respect to dissolved oxygen. Oxygen partial pressures ranging from 0.08 to 0.42 atm and sulfite concentrations varying between 0.002 and 0.04M are studied with well-stirred experiments.

Sodium dodecyl sulfate and sulfite improve some functional properties of soy protein concentrates

Abstract: The effects of sodium dodecyl sulfate (SDS) and sodium sulfite were studied on dispersibility, water and oil absorption of soy protein concentrates from toasted soy flours. Dispersibility was improved from 6.2% to 65% by 0.5% SDS, 0.25% sodium sulfite at pH6, and 60°C. Water absorption was improved from 5.5 to 7 mL water/g concentrate by 0.5% SDS at pH 6 at 20°C. Oil absorption was improved from 4.1 to 5.9 mL oil/g concentrate by 0.5% SDS, 0.25% sodium sulfite at pH 6 and 20°C.

Separation of Channel Catfish Eggs in Sodium Sulfite with and without Papain

Abstract: Two chemical solutions, 1.5% sodium sulfite and 1.5% sodium sulfite with 0.2% papain, were compared for their efficacy in separating the glycoprotein matrix of spawns from channel catfish (Ictalurus punctatus). The performance of the solutions was evaluated by comparing the numbers of live fry obtained per kilogram of egg mass. No significant differences in the performance of the solutions were detected, and it was concluded that the use of papain does not appear to be necessary.

Effects of alkali charge in bagasse chemimechanical pulping. I

Abstract: The effects of wet depithing of fresh and stored bagasse were initially studied. Intense wet depithing in the presence of a chelating agent reduces colour and metal ions content. The effects of sodium hydroxide charge up to 5% in cold soda chemimechanical pulping of depithed bagasse were later studied. Pretreatment at 90°C is detrimental to pulp colour. With a low alkali charge darkening can be diminished if a low temperature (80°C) is used; for higher charges the temperature has to be reduced further. Wet bulk stored bagasse darkens less than fresh bagasse and is also more responsive to the action of sodium sulfite

Influence of sodium sulfate or sodium sulfite on the solubilization of benzylalcohol in cationic micellar solutions

Abstract: The enthalpy of benzylalcohol (BzOH) solution has been determined as a function of alcohol concentration in aqueous trimethyltetradecylammonium bromide (TTAB) solutions in the presence of sodium sulfite or sodium sulfate up to high salt concentration. The electrolytes studied do not seem to induce TTAB sphere-torod transition at least up to 0.6 mol/kg of salt. Comparison with the enthalpic behavior of BzOH in sodium dodecylsulfate solutions and with that of 1-pentanol in both cationic and anionic micellar solutions suggests that the solubilization of BzOH in TTAB solutions is specifically favored by intramolecular interactions between alcohol molecules within the cationic micelles. The replacement of the bromide counterions by the sulfite or sulfate ions has been studied using potentiometry with an ionselective electrode in the case of trimethylhexadecylammonium bromide (CTAB). No difference could be detected between the effects of either divalent anions on the rate of change of the bromide ion-condensation with the salt/surfactant concentration ratioR. The degree of counter-ion condensation on micellar surface depends not only on theR values, but also on the total surfactant concentration.

Rapid measuring method for phosphorus of organic material

Abstract: PURPOSE:To end wet ashing in a short period of time by subjecting an org. material to the wet ashing by concd. sulfuric acid and hydrogen peroxide water and determining phosphorus by a phosphorous-molybdic acid method. CONSTITUTION:Ignition may arise in some cases by dropwise addition of the hydrogen peroxide water if the amt. of the concd. sulfuric acid is too small. A long time is required if the amt. is too large and, therefore, the ratio of the concd. sulfuric acid and the hydrogen peroxide is specified to about 1:5 to 1:20. The concd. sulfuric acid is first added to the sample of the org. material to heat and carbonize the material. Vigorous reaction takes place and a pale yellowish or colorless transparent liquid is instantaneously obtd. if the hydrogen peroxide water is added to the dark brown sulfuric acid soln. A small volume of water is added to the liquid so as not to affect the analysis of absorbance after this wet ashing. The liquid is then treated with potassium permanganate and sodium sulfite after heating. The wet ashing time is thus speeded up. This soln. is diluted with water and a specified volume thereof is fraction collected and is made acidic after neutralization. The phosphorus is determined by the phosphorous-molybdic acid method.

Effect of an addition of sodium sulfite on the mutagenicity of chlorinated solutions of aquatic humic substances.

Abstract: The aim of this study was to understand better the effects of dechlorination treatments with S IV species and especially sodium sulfite (Na 2 SO 3 ) on the mutagenic activity of chlorinated drinking water. For this purpose, laboratory experiments were carried out with aqueous solutions of isolated aquatic humic substances. These compounds account for the bulk of organic matter present in most surface waters and are known to be precursors of many of the mutagens and halogenated organics which are produced during the chlorination stage in drinking water treatment

Assistant for enzymatic degumming of raw silk

Abstract: PURPOSE:To provide the subject assistant composed of sodium bicarbonate, sodium carbonate and neutral sodium sulfite, enabling uniform enzymatic degumming of raw silk without lowering the characteristic feeling of silk fiber and attaining a desired degumming loss by the adjustment of the amount of proteinase. CONSTITUTION:The objective assistant contains (A) sodium bicarbonate, (B) sodium carbonate and (C) neutral sodium sulfite preferably at weight ratios A:B of 1:3 to 3:1 and C:(A+B) of (5-4):1.

Cocurrent flow process for the manufacture of sodium sulfite and bisulfite solutions

Abstract: Sodium (bi)sulfites are produced by the steps of: (a) introducing a stream of aqueous sodium carbonate into the top end of a main packed column reactor; (b) introducing a stream of sulfur dioxide gas into the top end of the main packed column reactor concurrently with the stream of aqueous sodium carbonate; (c) allowing the aqueous sodium carbonate and sulfur dioxide to cocurrently flow downward from the top end of the main packed column reactor to the bottom of the column in a cocurrent flow, during which flow reaction occurs between the aqueous sodium carbonate and the sulfur dioxide to produce sodium (bi)sulfite; and (d) recovering the product sodium (bi)sulfite and a gas stream containing any excess sulfur dioxide from the bottom of the main packed column reactor. The product (bi)sulfite can be separated from the gas stream in a separate receiving vessel and then the gas is sent to a scrubber to remove residual SO2. The scrubber may be a second packed column reactor operating with cocurrent flow.

Kinetics and mechanism of the cytochrome c--sulfite reaction

Abstract: The reaction between the oxidized form of horse-heart cytochrome c and sodium sulfite in aqueous solution has been studied in the pH range 6.5 – 8.2. The reaction is first order in both oxidant and reductant, is accelerated by an increase in pH and is slowed down by addition of potassium chloride. An increase in pH results in an increase in the apparent activation energy (66-77kJ . mol -1 ). A mechanism in which both HSO 3 - and SO 3 2- act as reducing agents is proposed, the activation energies corresponding to the cyt c-HSO 3 - and cyt c-SO 3 2- reactions being 63 ± 4 and 79 ± 2 kJ mol -1 , respectively.

Production of water-absorptive resin

Abstract: PURPOSE:To obtain a water-absorptive resin having a low unpolymerized monomer content and high safety easily and inexpensively by polymerizing a monomer based on an alpha,beta-unsaturated carboxylic acid (salt) in an aqueous solution in the presence of a persulfate, a specified organic peroxide and a reducing agent. CONSTITUTION:A monomer mixture based on an alpha,beta-unsaturated carboxylic acid or its salt (e.g. sodium acrylate) and optionally containing another hydrophilic monomer (e.g. acrylamide) is dissolved in water. To this solution are added a persulfate (e.g. sodium persulfate), an organic peroxide of a 10hr half life temperature in water >=80 deg.C (e.g. t-butyl hydroperoxide) and a reducing agent (e.g. sodium sulfite). The obtained mixture is subjected to polymerization in an aqueous solution under an atmospheric pressure or above to obtain a water-absorptive resin. The obtained resin has excellent water absorptivity and high safety and can be desirably used for sanitary articles, etc.

Production of 1,1,1,2,2-pentafluoro-3,3-dichloropropane

Abstract: PURPOSE:To obtain the subject substance in a high yield and high selectivity at a low cost by reducing 1,1,1,2,2-pentafluoro-3,3,3-trichloropropane in an aqueous solution containing an alkaline metal sulfite and an alkaline (earth) metal phosphate. CONSTITUTION:1,1,1,2,2-Pentafluoro-3,3,3-trichloropropane is charged to an autoclave made of SUS together with an alkaline metal sulfite, an alkaline (earth) metal phosphate and water and reacted at 90-140 deg.C and 3-8 kg/cm G to obtain the subject substance. As the alkaline metal sulfite, either of an anhydride or a compound containing crystal water can be used and, e.g. sodium sulfite is used in an amount of 1.2-1.5 times mole of the raw material. As the metallic phosphate, e.g. K2HPO4 is used in an amount of 1.1-1.5 times mole of the raw material. The above-mentioned method is economical as expensive substances or equipments are not used.

Method for determining quantity of ribonucleic acid

Abstract: PURPOSE:To make it possible to determine the quantity of RNA with excellent detecting sensitivity by adding a specified reagent into the ribonucleic acid (RNA) which is oxidized with sodium periodate under acidic condition, heating the material, emitting fluorescent light, and measuring the fluorescent light. CONSTITUTION:Mineral acid such as hydrochloric acid and sulfuric acid and sodium periodate are added into a sample RNA. The material is left alone at room temperature, and oxidation is completed. Then sodium sulfite and 1, 2-diallyl ethylenediamine (DAED) are added into said oxidation reaction liquid. The liquid is heated, and fluorescence emitting reaction is completed. After the completion of the reaction, the liquid is cooled with water, and the intensity of the fluorescence is measured at the specified exciting wavelength and the heating wavelength. The quantity is determined by a calibration curve which is formed beforehand. In the mixed RNA, the sample is separated into the respective RNAs with high-speed liquid chromatography. Oxidation and fluorescence emitting reaction are performed in a reaction coil continuously. The liquid in this state is guided into a fluorscence detector, and the intensity of the fluorescence of each RNA can be measured and the quantity is deter mined.

Formation of sodium disulfite in a solid-gas system

Abstract: The formation of sodium disulfite by the heterogeneous reaction of solid active sodium sulfite with gaseous sulfur dioxide in the presence of water vapour was investigated over the temperature range of 293 to 393 K at SO 2 . H 2 O and O 2 partial pressures of 1.2-7.4, 1.2-6.4 and 0-11.3 kPa, respectively. The effect of the reaction time was also examined. Kinetic measurements were supplemented with the determination of the equilibrium dissociation pressure of SO 2 in contact with sodium sulfite at 373.15 K. The major aim of the work was to establish the optimum conditions for attaining the maximum degree of conversion of the solid reactant to sodium disulfite. The conditions for the formation of virtually pure sodium disulfite were found.

Dechlorination with Sodium Sulfite: Effect on the TOX Concentration and the Mutagenicity of Chlorinated Solutions of Aquatic Humic Substances

Abstract: This study shows that a decrease in the TOX content of chlorinated dilute solutions of aquatic humic substances could be observed under neutral or basic conditions after storage and/or sulfite addition. The mutagenicity tests performed directly on chlorinated samples of AHS concentrated solutions showed that the addition of sulfite could also reduce significantly the mutagenicity. The results obtained with partially or fully dechlorinated samples of AHS dilute solutions showed that only a complete dechlorination treatment could decrease the TOX level and the mutagenic activity of XAD extracts.