Sulfite Compounds Research Articles

Chemiluminescence spectra for the oxidation of sulphite in the presence of fluorescent and non-fluorescent enhancers

The spectral distribution of chemiluminescence provides key evidence in the elucidation of the reaction mechanism and emitting species. We have collected chemiluminescence spectra for the oxidation of sodium sulphite and captopril in the presence of a range of fluorescent and non-fluorescent enhancers. This evidence was used to evaluate several previously proposed light-producing pathways, and revealed some new approaches to enhance the chemiluminescent oxidation of sulphite and thiol compounds. Chemiluminescence reactions between sulphite and permanganate produce two potential emitters: one derived from the oxidation of sulphite (in some cases via energy transfer to a more efficient luminophore) and another derived from the reduction of permanganate. This second light-producing pathway is rarely considered in discussions on the chemiluminescent oxidation of sulphite, but can make a significant contribution to the overall emission. Non-fluorescent enhancers of sulphite chemiluminescence result in several distinct spectral distributions and, contrary to previous postulation, these reactions are unlikely to lead to the same emitting species. Non-fluorescent enhancers of sulphite chemiluminescence can also significantly increase the weak emission from the oxidation of thiol compounds such as captopril.

The Crystal Structure of Desulfovibrio vulgaris Dissimilatory Sulfite Reductase Bound to DsrC Provides Novel Insights into the Mechanism of Sulfate Respiration

Sulfate reduction is one of the earliest types of energy metabolism used by ancestral organisms to sustain life. Despite extensive studies, many questions remain about the way respiratory sulfate reduction is associated with energy conservation. A crucial enzyme in this process is the dissimilatory sulfite reductase (dSiR), which contains a unique siroheme-[4Fe4S] coupled cofactor. Here, we report the structure of desulfoviridin from Desulfovibrio vulgaris, in which the dSiR DsrAB (sulfite reductase) subunits are bound to the DsrC protein. The alpha(2)beta(2)gamma(2) assembly contains two siroheme-[4Fe4S] cofactors bound by DsrB, two sirohydrochlorins and two [4Fe4S] centers bound by DsrA, and another four [4Fe4S] centers in the ferredoxin domains. A sulfite molecule, coordinating the siroheme, is found at the active site. The DsrC protein is bound in a cleft between DsrA and DsrB with its conserved C-terminal cysteine reaching the distal side of the siroheme. We propose a novel mechanism for the process of sulfite reduction involving DsrAB, DsrC, and the DsrMKJOP membrane complex (a membrane complex with putative disulfide/thiol reductase activity), in which two of the six electrons for reduction of sulfite derive from the membrane quinone pool. These results show that DsrC is involved in sulfite reduction, which changes the mechanism of sulfate respiration. This has important implications for models used to date ancient sulfur metabolism based on sulfur isotope fractionations.

Raman spectroscopic study of the sulfite‐bearing minerals scotlandite, hannebachite and orschallite: implications for the desulfation of soils

AbstractThe structures of the naturally occurring sulfite‐bearing minerals scotlandite, hannebachite and orschallite have been studied by Raman spectroscopy. Raman bands are observed for scotlandite PbSO3 at 935, 880, 622 and 474 cm−1 and are assigned to the (SO3)2−ν1(A1), ν3(E), ν2(A1) and ν4(E) vibrational modes, respectively. For hannebachite (CaSO3)2·H2O these bands are observed at 1005, 969 and 655 cm−1 with multiple bands for the ν4(E) mode at 444, 492 and 520 cm−1. The Raman spectrum of hannebachite is very different from that of the compound CaSO3·2H2O. It is proposed, on the basis of Raman spectroscopy, that in the mineral hannebachite, the sulfite anion bonds to Ca through the sulfur atom. The Raman spectrum of the mineral orschallite Ca3[SO4](SO3)2·12H2O is complex resulting from the overlap of sulfate and sulfite bands. Raman bands at 1005 cm−1, 1096 and 1215 cm−1 are assigned to the (SO4)2−ν1 symmetric and ν3 asymmetric stretching modes. The two Raman bands at 971 and 984 cm−1 are attributed to the (SO3)2−ν3(E) and ν1(A1) stretching vibrations. The formation of sulfite compounds in nature offers a potential mechanism for the removal of sulfates and sulfites from soils. Copyright © 2008 John Wiley & Sons, Ltd.

Polyoxomolybdenum(V)/(VI)—Sulfite Compounds: Synthesis, Structural and Physical Studies.

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Polyoxomolybdenum(V/VI)−Sulfite Compounds: Synthesis, Structural, and Physical Studies

Reaction of Na(2)Mo(VI)O(4) x 2H(2)O with (NH(4))(2)SO(3) in the mixed-solvent system H(2)O/CH(3)CN (pH = 5) resulted in the formation of the tetranuclear cluster (NH(4))(4)[Mo(4)(VI)SO(16)] x H(2)O (1), while the same reaction in acidic aqueous solution (pH = 5) yielded (NH(4))(4)[Mo(5)(VI)S(2)O(21)] x 3H(2)O (2). Compound {(H(2)bipy)(2)[Mo(5)(VI)S(2)O(21)] x H(2)O}(x) (3) was obtained from the reaction of aqueous acidic solution of Na(2)Mo(VI)O(4) x 2H(2)O with (NH(4))(2)SO(3) (pH = 2.5) and 4,4'-bipyridine (4,4'-bipy). The mixed metal/sulfite species (NH(4))(7)[Co(III)(Mo(2)(V)O(4))(NH(3))(SO(3))(6)] x 4H(2)O (4) was synthesized by reacting Na(2)Mo(VI)O(4) x 2H(2)O with CoCl(2) x 6H(2)O and (NH(4))(2)SO(3) with precise control of pH (5.3) through a redox reaction. The X-ray crystal structures of compounds 1, 2, and 4 were determined. The structure of compound 1 consists of a ring of four alternately face- and edge-sharing Mo(VI)O(6) octahedra capped by the trigonal pyramidal sulfite anion, while at the base of the Mo(4) ring is an oxo group which is asymmetrically shared by all four molybdenum atoms. Compound 3 is based on the Strandberg-type heteropolyion [Mo(5)(VI)S(2)O(21)](4-), and these coordinatively saturated clusters are joined by diprotonated 4,4'-H(2)bipy(2+) through strong hydrogen bonds. Compound 3 crystallizes in the chiral space group C2. The structure of compound 4 consists of a novel trinuclear [Co(III)Mo(2)(V)SO(3)(2-)] cluster. The chiral compound 3 exhibits nonlinear optical (NLO) and photoluminescence properties. The assignment of the sulfite bands in the IR spectrum of 4 has been carried out by density functional calculations. The cobalt in 4 is a d(6) octahedral low-spin metal atom as it was evidenced by magnetic susceptibility measurements, cw EPR, BVS, and DFT calculations. The IR and solid-state UV-vis spectra as well as the thermogravimetric analyses of compounds 1-4 are also reported.

The effect of surfactants on organic dye separation by ultrafiltration

Textile effluents contain many chemical substances arising from desizing, dyeing, printing and finishing processes. Moreover the quality of textile wastewaters is variable with time and depends on the kind of process that generates the effluents. Textile exhausted baths may include many types of detergents, sulphite compounds, solvents, heavy metals and inorganic salts in various amounts. Surfactants which are used as levelling, dispersing and wetting agent in the dyeing process, mostly act in two ways: they can create a complex formation with ionic dye or they can adsorb with non-ionic dye into the fibre. Interactions between surfactant and dye particles in aqueous solutions are of great importance in the view of effluent treatment and water reuse. Membrane processes can be used for the purification of exhausted dye baths and water regeneration [1,2]. In the present work, the low pressure membrane process has been studied in order to treat aqueous solutions containing both dye and surfactant. The effect of anionic surfactant on the separation efficiency of various textile dyes was analyzed.

Oxovanadium(IV)-sulfite compounds: Synthesis and structural and physical studies

Abstract Reaction of VIVOCl2 in strongly acidic aqueous solution with either (NH4)2SO3 or Na2SO3 and Bu4NBr at ~70°C in the pH range 2.5-4.5 gives the clusters (NH4)2{[V4 IV(μ 4-O)2(μ 3-OH)2](VIVO)2(μ 3-SO3)4O4(H2O)2} and (n-Bu4N)2{[V4 IV(μ 4-O)2(μ 3-OH)2](VIVO)2(μ 3-SO3)4O4(H2O)2}, respectively. Reaction of NH4VVO3 with (NH4)2SO3 resulted in the isolation of the first compound. When the latter reaction is carried out in the presence of MgO, compound (NH4)[VIVO(SO3)1.5H2O]∞.2.5H2O was isolated instead. Compound (n-Bu4N)2{[V4 IV(μ 4-O)2(μ 3-OH)2](VIVO)2(μ 3-SO3)4O4(H2O)2} and (NH4)[VIVO(SO3)1.5H2O]∞.2.5H2O were characterized by X-ray structure analysis. The crystal structure of species (n-Bu4N)2{[V4 IV(μ 4-O)2(μ 3-OH)2](VIVO)2(μ 3-SO3)4O4(H2O)2} revealed a unprecedented hexanuclear cluster consisting of a cubane core [M4(μ 4-O)2(μ 3-OH)2] connected to two other metal atoms through the core oxo-groups and four μ 3-SO3 bridges. Compound (NH4)[VIVO(SO3)1.5H2O]∞.2.5H2O represents a rare example of an open-framework species prepared under mild conditions. Cyclic voltammetric examination of compound (n-Bu4N)2{[V4 IV(μ 4-O)2(μ 3-OH)2](VIVO)2(μ 3-SO3)4O4(H2O)2} revealed a redox process which was assigned to the oxidation of one core of vanadium(IV) to vanadium(V).

Variation of pH in reaction of sodium sulfide with carbonyl compounds

The results of an experimental study of how pH varies in the course of a reaction between sodium sulfite and carbonyl compounds are presented.

Treatment of effluents from petroleum production by electron beam irradiation

During the offshore oil production large volumes of aqueous waste with high salinity are produced. The produced water originates mainly from the oil-bearing formation but may also include seawater, which has been injected to maintain reservoir pressure. This water is normally separated from oil on the platform generating aqueous effluent with metals, sulfite, ammonium and organic compounds. The conventional treatment used includes filtration, flotation, ionic change and adsorption in activated charcoal, but the high salinity of this water decreases the treatment efficiency. The high efficiency of electron beam irradiation on removing organic compound in industrial effluent has been shown, and the primary aim of this study is to evaluate the efficiency of this new technology to treat the oil water production. Experiments were conducted using samples from two platforms processed in the radiation dynamics electron beam accelerator with 1.5 MeV energy and 37 kW power. The results showed that the electron beam technology has high efficiency in destroying organic compounds even in the presence of high salinity and complex effluent.

Sulfur- and phosphorus- Kβ spectra analyses in sulfite, sulfate and phosphate compounds by X-ray fluorescence spectrometry

Several sulfite, sulfate and phosphate compounds were studied by X-ray fluorescence spectrometry. Sulfur- and phosphorus- Kβ spectral profile modified by the number of bonding hydrogen and oxygen atoms were analyzed. As it could be confirmed, the molecular orbital theory provides a suitable explanation of the origin and properties of the satellite Kβ′ lines. Also, for the compounds analyzed, it was found that sulfur- and phosphorus- Kβ spectra present two main components and two secondary ones which exhibit a different behavior depending on the number of bonding hydrogen and oxygen atoms. Particularly, the peak corresponding to satellite Kβ′ line increases its intensity and moves away from the main peak when the number of oxygen atoms combined with the sulfur atom is increased. The energy differences between the main peak and the satellite peak found in the analyzed compounds were in average 14.2±0.4 eV, thus being demonstrated that such a separation is a characteristic of the bonding atom, in this instance oxygen.

Polyoxovanadium(IV) Sulfite Compounds: Synthesis, Structural, and Physical Studies.

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Coulometric Titrations in Wine Samples: Studies on the Determination of S(IV) and the Formation of Adducts

In this experiment, the sulfite in white wine samples is quantified by coulometric titration with iodine, using a procedure that minimizes errors due to air oxidation. Some aspects of the distinction of S(IV) forms in such matrices are discussed on the basis of the formation of adducts between sulfite and carbonyl compounds present in the wine. The reactivity of these S(IV)-bound compounds toward the reaction with iodine is addressed and the stability of the adducts as the sample pH is changed is discussed.

Effect of Various Acids and Sulfites in Steep Solution on Yields and Composition of Corn Fiber and Corn Fiber Oil

ABSTRACTThe addition of six acids (organic and inorganic) and four sulfite compounds (including gaseous SO2) during the conventional corn wet‐milling steeping process of two yellow dent corn hybrids were evaluated for the effect on corn fiber yield, corn fiber oil yield, and the composition of three phytosterol compounds (ferulate phytosterol esters [FPE], free phytosterols [St], and phytosterol fatty acyl esters [St:E]) in the corn fiber oil. No significant effect of different sulfite compounds and acids were observed on corn fiber yields. However, a significant effect was observed on corn fiber oil yield and the composition of corn fiber oil for phytosterol compounds. Three of the sulfite compounds (including gaseous SO2) caused very little effect on the levels of phytosterol compounds compared with the control sample (corn steeped with sodium metabisulfite and lactic acid). However, for one hybrid, ammonium sulfite gave a significantly higher yield of FPE and St:E and had no effect on the yield of St. For the other hybrid, it gave a significantly higher yield of FPE and had no effect on the yield of St and St:E compared with the control sample. This indicates that the effect of these sulfite compounds on yields of these phytosterol compounds in corn fiber oil is probably hybrid‐dependent. No significant effect of acids was observed on corn fiber yields, but significant effects were observed on corn fiber oil yields and yields of phytosterol compounds in the corn fiber oil. The effect also seems to be hybrid‐dependent because different acids affected the two hybrids differently. Overall, it seems that weak acids have a positive effect on increasing the individual phytosterol compounds in the corn fiber. When comparing the effect of experimental acids and sulfites on the two hybrids, acids have a more positive effect than sulfites in increasing the yield of phytosterol compounds in corn fiber oil.

Response of Broiler Chicks to Supplemental Inorganic Sulphate and Sulphite Compounds in a Tropical Environment

Ologhobo, A.D., Jimoh, J.O. and Ayoade, G.O. 1998. Response of broiler chicks to supplemental inorganic sulphite and sulphate compounds in a tropical environment. J. Appl. Anim. Res., 14: 151–157. A feeding trial was conducted to determine the effectiveness of sulphate and sulphite compounds in sparing sulphur amino acid, methionine, in broiler chicks raised under a tropical environment. A significant (P<0.05) growth response was obtained by the addition of 0.30% DL-methionine or 0.15% methionine plus 0.10% sodium sulphate (Na2 SO4) to a corn-soybean basal diet confirming that the diet was deficient in methionine. Enhanced levels of serum protein (P<0.05) in diets supplemented with 0.3% methionine indicated good nutritional status of birds. The hypothesis is advanced that there is either a dietary requirement for sulphate “per se” or that sulphate spares methionine through conversion to cystine.

CTMP Wastewater Treatment Using a Rotating Biological Contactor

Abstract Studies on the treatment of CTMP mill wastewater were done using a laboratory-scale rotating biological contactor (RBC). Analysis of the wastewater is given. The effects of organic loading rates in the range 0.007 to 0.033 kg BOD m-2 day1 (0.012 to 0.055 kg COD m-2 day-1) and temperature (20 and 31°C) on the percent removal of BOD and COD are presented. Average BOD (COD) removals ranged from 70% (46%) at 20°C to 86% (72%) at 31°C. The acetic acid content of the wastewater was almost completely biologically oxidized in the RBC and very little acetic acid volatilization was observed. Sulfite and sulfide compounds tended to be oxidized to sulfate compounds during the RBC treatment. Over the range of dissolved oxygen (DO) concentrations (0.3 to 2.0 mg/L) measured in the RBC trough, DO appeared to have no effect on BOD removal, even though some of these DO levels were very low. The discs carried wet microbial biofilms of the order of 0.5 kg m-2. Biomass sloughed off the discs at a rate that was approximately 0.04 kg m-2 day-1.

Study on the gaseous emissions from a landfill

Emissions from landfills contain a variety of compounds, organic and inorganic, which can create problems with human health. Here we examine the pollutants methane, hydrogen sulphite, mercaptans, sulphur dioxide, nitrogen dioxide and certain volatile organic compounds (VOCs) that are expected to be found in landfill emissions, in order to assess the environmental impact on the surrounding area. Results indicate that the concentrations in the landfill itself are quite high and in most cases above the ambient air quality limits, while for the surrounding area they are low. The problem is created by H 2S and the mercaptans which, although in low content, have a distinct odour and cause problems to the neighbouring dwellings.

Oxidation and Reduction of Sulfite by Chloroplasts and Formation of Sulfite Addition Compounds

After exposing intact chloroplasts isolated from spinach (Spinacia oleracea L. cv Yates) and capable of photoreducing CO(2) at high rates to different concentrations of radioactive sulfite in the light or in the dark, (35)SO(2) and H(2) (35)S were removed from the acidified suspensions in a stream of nitrogen. Remaining activity could be fractionated into sulfate, organic sulfides, and sulfite addition compounds. When chloroplast suspensions contained catalase, superoxide dismutase and O-acetylserine, the oxidation of sulfite to sulfate was slower in the light than the reductive formation of sulfides that exhibited a maximum rate of about 2 micromoles per milligram chlorophyll per hour, equivalent to about 1% of maximum carbon assimilation. Botht the oxidative and the reductive detoxification of sulfite were very slow in the dark. Oxidation was somewhat, but not much, accelerated in the light in the absence of O-acetylserine, which caused a dramatic decrease in the formation of organic sulfides and an equally dramatic increase in the concentration of sulfite addition compounds whose formation was light-dependent. The sulfite addition compounds were not identified. Addition compounds did not accumulate in the dark. In the light, the electron transport inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea, diuron, decreased not only the reduction, but also the oxidation of sulfite and the formation of addition compounds.

Kinetic determination of some inorganic and organic compounds by oxidation with iodate

Sulphite (5.0 × 10 −1−5.0 × 10 −3 M), ascorbic acid and other compounds are oxidized by potassium iodate in dilute sulphuric acid; the production of iodide is monitored by an iodide-selective electrode. The time needed for a 40-mV potential change is inversely proportional to concentration. For sulphite (1.0 × 10 −5−1.0 × 10 −4 M), selectivity is improved by sweeping the sulphur dioxide formed in acidic EDTA-containing solution into the iodate solution.

Quenched peroxyoxalate chemiluminescence detection in aqueous liquid chromatographic separations

Several analytes, such as bromide, iodide, sulphite, nitrite, substituted anilines and organosulphur compounds cause quenching of peroxyoxalate chemiluminescence. This phenomenon, quenched peroxyoxalate chemiluminescence, can be used as a method of detection for liquid chromatography. The potential of quenched chemiluminescence is discussed, with special attention give to its compatibility with aqueous separation systems. An immobilized fluorophore, 3-aminofluoranthene on controlled pore glass, is packed in the detector cell. Liquid-state studies show that the influence of both the nature and concentration of the fluorophore is small, which indicates a more complicated mechanism of the chemiluminescence reaction than previously assumed. It is shown that bis(2-nitrophenyl)oxalat is a more suitable oxalate for quenched chemiluminescence detection than bis(2,4,6-trichlorophenyl) oxalate. This is demostrated for ion-chromatography of bromide and iodide and the aqueous reversed-phase separation of organosulphur compounds. Detection limits in the low nanogram and sub-nanogram region are reported for the above compounds. When an electronic inverter was used, calibration curves were linear over a concentration range of 2–3 decades. The method is quite selective and can be applied to relatively complex matrices without sample pretreatment.

Cooperative effect of sulfite and vanadium compounds on lipid peroxidation

The cooperative mechanism of the action of sulfite and metal compounds on lipid peroxidation was investigated in vitro. Results obtained were as follows: (1) Lipid peroxidation of rat lung extracts, liver microsomes, and mitochondria was induced by sulfite, depending on its concentration. Peroxidation was accelerated remarkably by metal compounds such as iron or vanadium. (2) The increased lipid peroxidation by sulfite and vanadium was inhibited effectively by free radical scavengers such as hydroquinone, α-tocopherol, or superoxide dismutase. (3) Similar effect of these radical scavengers was seen in lipid peroxidation induced by superoxide anion radical. (4) In the presence of sulfite and vanadium, a significant lysis of human erythrocytes was caused, suggesting an additive action of the effect of these substances.