Presence Of Sodium Sulfide Research Articles

Exalted Level of Nitrogen Metabolism In the Presence of Sodium Sulphide in Nostocellipososporum under Thermal Stress

It is well-recognized that thermophilic cyanobacteria flourish in sulfur-rich thermal springs. Mesophilic cyanobacteria are available at temperatures ranging from 28 to 37°C. This study sought to determine if mesophilic cyanobacteria can also grow at elevated temperatures in the presence of sulphide, and if yes ,then what role sulfide would have in reducing high temperature stress in mesophilic cyanobacterial organisms. The prolifecation of Nostoc ellipososporum, a mesophilic cyanobacterium, was examined at its optimal temperature, both in the presence and absence of sulphide under thermal stress. During the current investigation, nitrate uptake was seen to slow down under temperature stress, but when sulphide was added to the cultures, nitrate uptake increased. This demonstrates that increased levels of nitrogen metabolism in the presence of sulphide contributed to the survival of the test organism under temperature stress.

Electrical Study of Changes in Impedance and Internal Parameters of Nano Structures of Molybdenum Disulfide Semiconductor Type (MoS2-2H/3R) with Changes in Temperature

MoS2 nanostructures were prepared using the hydrothermal method by reacting ammonium heptamolybdate tetrahydrate ((NH4)6Mo7O244H2O) with citric acid monohydrate (C6H8O7H2O) in distilled water with the presence of sodium sulfide (Na2S), we have found from the Arenos diagram that the value of the activation energy of (MoS2 -2H/3R) is low and equal to Ea= 0.0505 (e.V). From the atomic force microscope (AFM) images, we found that the size of the surface aggregates of the sample (table - MoS2-2H/3R) ranges between (100-150) n m. From studying the changes in the impedance with different temperatures (T = 15, 30, and 60), we found that impedance is inversely proportional to both the applied frequency and the temperature, and at the frequencies the response corresponding to the temperature reaches a value of (Z = 20 K.Ω, T = 15°C). ) and at temperature (Z = 8.02 K.Ω, T = 30 °C), and at (Z = 17.1 K.Ω, T = 60 °C), It has been shown that the number of electric charge carriers (Nd) increases with increasing temperature. On the contrary, we found a decrease in the number of electronic traps (Ns) and a decrease in the relaxation time τP with increasing temperature.

Preparation of glycosyl disulfides and sulfides via the formation of glycosyl Bunte salts as thiol surrogates

A convenient odourless reaction condition has been developed for the preparation of symmetrical glycosyl disulfide derivatives and aryl glycosyl disulfide derivatives from corresponding glycosyl iodides via in situ formation of glycosyl Bunte salts as thiol surrogates. The reaction has been further extended towards the preparation of glycosyl sulfides derivatives from corresponding Bunte salt in the presence of sodium sulphide. Most of the reactions were high yielding and suitable for scaling up.

Sulfur-doped graphene aerogels reinforced with carbon fibers as electrode materials

In this work, the development of a novel sulfur-doped graphene aerogel composite reinforced with carbon fibers (CFs) is presented. Sulfur is entrapped between the graphene nanosheets when GO in the presence of sodium sulfide is reduced hydrothermally to rGO forming a stable hydrogel and an aerogel after freeze-drying. The simultaneous incorporation of CFs improves the mechanical stability of the final composite. The as-prepared composite combines the characteristics of graphene aerogels such as porosity, surface area, chemical inertness with the mechanical properties of CFs and the ability of sulfur to capture lithium, thus providing a material with promising electrochemical properties for lithium-ion battery applications.

Influence of Sulphides on Hydration of Ground Granulated Slag Alkali Activated Mortars and Pastes

Influence of sodium sulphide on properties of sodium hydroxide activated ground granulated blast furnace slag was investigated. Properties of both fresh (cone flow, density) as well as hardened (compressive strength) mortars were determined. Early hydration of pastes was investigated using conducting calorimetry. Results showed, that introduction of sodium sulphide to caustic soda activated slag only slightly influence the course of hydration process. Early strength is increased by about 10%. In later periods strength is virtually not affected by the presence of sodium sulphide. Those observations are confirmed by calorimetric results. Presence of sodium sulphide causes slight decrease in consistency of mortars. Colour of mortars is also affected by the presence of sulphides. It is more darker and it is most probably due to the reducing properties of sulphide ions. Results of model investigations on precipitated C-S-H phase showed, that presence of sulphides results in increased main basal spacing of C-S-H phase as determined by XRD.

Effect of copper ions on the flotation separation of chalcopyrite and molybdenite using sodium sulfide as a depressant

Copper ions are unavoidable in the process of copper-molybdenum flotation separation. The flotation response of chalcopyrite and molybdenite in the presence of copper ions was investigated through single mineral flotation tests and flotation separation tests. The influence mechanism was studied by adsorption experiments, zeta-potential measurements, and X-ray photoelectron spectroscopy (XPS) analysis. Flotation results indicated that copper ions dramatically reduced the recoveries of copper and molybdenum, and increased the inhibition effect of sodium sulfide; that is, the flotation separation of chalcopyrite and molybdenite was seriously hindered by copper ions. The adsorption experiments demonstrated that copper ions were adsorbed on molybdenite and chalcopyrite, and the adsorption amounts increased in the presence of sodium sulfide. The results of zeta-potential measurements confirmed that the floatability of the minerals was deteriorated by the adsorption of copper hydroxides (Cu(OH)+ and Cu(OH)2) and the subsequent adsorption of hydrosulfide ions (HS−). Moreover, XPS analysis verified that the adsorbed copper hydroxides reacted with hydrosulfide ions, producing Cu(I)-S species on the surface of chalcopyrite and molybdenite. The adsorbed Cu(I) ions provided additional reaction sites and promoted the formation of a hydrophilic layer by the attachment of excessive hydrosulfide ions. Based on these analyses, a possible inhibition model for the interactions among the mineral surface, copper ions, and sulfide ions is proposed.

Chalcopyrite and pyrite floatabilities in the presence of sodium sulfide and sodium metabisulfite in a high pyritic copper complex ore

ABSTRACTOne of the principal problems in flotation of copper complex ores is the presence of pyrite and copper-activated pyrite in moderately alkaline pHs. Misreported pyrite into copper concentrates dramatically declines copper grade and its recovery. In this study, the effect of sodium sulfide, sodium metabisulfite (SMBS), and their dosages (100, 200, 300, and 400 g/t) were investigated on chalcopyrite and pyrite floatabilities in a high pyritic copper sulfide ore. Furthermore, the role of particle size distribution (PSD) in three different levels (i.e., d70, d75, and d80 of passing 75 µm) was evaluated by a series of batch flotation experiments. It was revealed that using 200 g/t SMBS provides not only the highest and the lowest chalcopyrite and pyrite recoveries, but also the maximum and minimum copper and iron grades. Pyrite recovery was sharply increased by the addition of sodium sulfide in light of sodium sulfide-induced collectorless flotation; however, it showed a very weak effect on chalcopyrite floatability. In addition, the highest and lowest chalcopyrite and pyrite recoveries were, respectively, identified when d75 equaled to 70% 75 µm. In other words, for the high pyritic copper ore type, it is feasible to achieve the highest chalcopyrite recovery consuming the lowest grinding energy.

Transformations of citrate and Tween coated silver nanoparticles reacted with Na2S

Silver nanoparticles (Ag NPs) are susceptible to transformations in environmental and biological media such as aggregation, oxidation, dissolution, chlorination, sulfidation, formation/replacement of surface coatings following interaction with natural organic matter (NOM). This paper investigates the impact of surface coating and Suwannee River fulvic acid (SRFA) on the transformations and behavior of Ag NPs (citrate coated and Tween coated; cit-Ag NPs and Tween-Ag NPs, respectively), following reaction with different concentrations of Na2S solution (as a source of sulfide species, H2S and HS−). These transformations and the dominant mechanisms of transformations were investigated using UV–vis and scanning transmission electron microscopy coupled with electron energy loss spectroscopy.Here, we have shown that Ag NP surface coating impacts their dissolution following dilution in ultrahigh purity water, with higher extent of dissolution of Tween-Ag NPs compared with cit-Ag NPs. Tween-Ag NPs are susceptible to dissolution following their sulfidation at low S/Ag molar ratio. Suwannee River fulvic acid (SRFA) slows down the dissolution of Tween-Ag NPs at low sulfide concentrations and reduces the aggregation of cit-Ag NP in the presence of sodium sulfide. Sulfidation appears to occur by direct interaction of sulfide species with Ag NPs rather than by indirect reaction of sulfide with dissolved Ag species subsequent to dissolution. Furthermore, the sulfidation process results in the formation of partially sulfidized Ag NPs containing unreacted (metallic) subgrains at the edge of the NPs for Tween-Ag NPs in the presence of high sulfide concentration (2000nM Na2S), which occurred to less extent at lower Na2S concentration for Tween-Ag NPs and at all concentrations of Na2S for cit-Ag NPs. Thus, sulfidized Ag NPs may preserve some of the properties of the Ag NPs such as their potential to shed Ag+ ions and their toxic potential of Ag NPs.

ChemInform Abstract: Methods for the Synthesis of Chiral Sulfur Heterocycles and Their Application in the Asymmetric Baylis—Hillman Reactions.

AbstractDimesylates of chiral diols cyclize in the presence of sodium sulfide to provide sulfur heterocycles (III) and (VII).

Corrosion Study of Super Ferritic Stainless Steel UNS S44660 (26Cr-3Ni-3Mo) and Several Other Stainless Steel Grades (UNS S31603, S32101, and S32205) in Caustic Solution Containing Sodium Sulfide

Electrochemical techniques, scanning electron microscopy (SEM), and X-ray photoelectron spectroscopy (XPS) were used in this study to show how the corrosion mechanism of several commercial grades of stainless steel in hot caustic solution is strongly influenced by the presence of sodium sulfide. Experimental results from super ferritic stainless steel UNS S44660 (26Cr-3Ni-3Mo) were compared to austenitic stainless steel UNS S31603, lean duplex stainless steel (DSS) UNS S32101, and standard DSS UNS S32205 in caustic solution, with and without sodium sulfide, at 443 K (170 °C). Weight loss measurements indicated that corrosion rates of UNS44660 were much lower than the other grades of stainless steel in the presence of the sodium sulfide. Potentiodynamic polarization and linear polarization resistance measurements showed that the electrochemical behavior was altered by the adhesion of sulfur species, which reduced the polarization resistances and increased the anodic current densities. SEM and XPS results imply that the surface films that formed in caustic solution containing sodium sulfide were defective due to the adsorption of sulfide, which destabilized the passive film and led to the formation of insoluble metal sulfide compounds.

ChemInform Abstract: Synthesis of 2‐Substituted Benzothiazoles from 1‐Iodo‐2‐nitrobenzenes by a Copper‐Catalyzed One‐Pot Three‐Component Reaction.

AbstractA broad spectrum of 2‐substituted benzothiazoles is available in the presence of sodium sulfide, where a wide range of functional groups is tolerated at the arene moieties of the substrates.

Wood capillarity and deacetylation during eucalyptus alkaline impregnation. Sulphidity effects and comparison between transverse directions

Abstract The relative ion transport capacity of wood – the “effective capillary cross sectional area" (ECCSA) – is determined in this work, based on the analogy with the relation between the electrical conductivities of wood and liquid medium. Wood was treated under different conditions and then the corresponding ECCSAA (the index A is for alkali) is estimated from the value obtained in an inert solution at room temperature (ECCSAInert). The difference between radial and tangential ECCSAA values is constant irrespective of pH, time, temperature and the presence of sodium sulfide in the treatment liquor. The results show that ECCSAA is dependent on the degree of removal of native acetyl groups from hardwood O-acetyl-glucuronoxylan. A kinetic expression for Eucalyptus wood deacetylation is validated and used to establish the relationship between the acetyl content and ECCSAA in both anatomical directions.

An efficient electrochemical method for the synthesis of methylene blue

An efficient and one-pot electrochemical method for the synthesis of methylene blue based on the Michael-type reaction of electrochemically generated quinone-diimine derived from oxidation of N, N-dimethyl- p-phenylenediamine in the presence of sodium sulfide as nucleophile in aqueous solution via EC-ECECC mechanism is reported.

Smithsonite flotation using mixed anionic/cationic collector

The surface interaction and adsorption of the components in a mixture of surfactants are of considerable interest for both practical and theoretical reasons. The flotation behaviour of smithsonite in the presence of sodium sulphide (Na2S) and a mixture of potassium amyl xanthate (KAX) and dodecylamine (DDA) and its adsorption on smithsonite surface at various concentration ratios have been investigated using zeta potential, contact angle, microflotation and diffuse reflectance FTIR studies. The smithsonite mineral has weak response to flotation in the presence of KAX alone as a collector. The presence of KAX enhanced the amine flotation recovery in the presence of sodium sulphide. The flotation results using mixed collectors showed the maximum recovery and contact angle were 95·5% and 104° at pH 12 respectively. The FTIR spectra revealed the coadsorption as amine–xanthate complex when mixed collector is used. The presence of KAX increased the DDA adsorption due to decrease in the electrostatic head–head repulsion between the two adjacent surface ammonium head group cations because the anionic KAX sitting between these two cations screens the electrostatic repulsion and increased the lateral tail–tail hydrophobic bonds.

Effects of sodium sulfide on burrowing activity of Capitella sp. I and bacterial respiratory activity in seawater soft-agar microcosms

We applied the seawater soft-agar microcosm approach in order to reveal the effects of sodium sulfide on burrowing activity of Capitella sp. I and on bacterial respiratory activity on mucus-lined burrow. The presence of sodium sulfide up to 7 mM in the soft-agar was not detrimental to the burrowing activity and the survival of the worms, but seemed to enhance the secretion of mucus from the worms. Addition of INT into overlying water (0.01% v/v) of the soft-agar microcosms containing the same concentrations of sodium sulfide caused intensive deposition of INT-formazan in the water, on the mucus over soft-agar surface and on the burrow lining. Both image analyses and spectrophotometric determination of the red-color INT-formazan showed a marked increase in the presence of 3.5 mM sulfide. From these results, we concluded that sulfide can promote burrowing activity of Capitella sp. I and thus enhance the bacterial respiratory activity on the burrow lining. These findings will help clarify the possible interaction between Capitella worms and sulfur-oxidizing bacteria in organically-enriched, sulfide rich sediment in natural environments.

Dimethylthioarsenicals as arsenic metabolites and their chemical preparations.

Two unidentified arsenic metabolites were detected in the liver of rats on a gel filtration column by HPLC inductively coupled argon plasma mass spectrometry after an injection of dimethylarsinic (DMA(V)), dimethylarsinous (DMA(III)), monomethylarsonic (MMA(V)), or monomethylarsonous (MMA(III)) acid. The same arsenicals were also produced in vitro by incubation of DMA(III) in the liver supernatant but not by DMA(V). The two arsenic metabolites eluted at the same retention times as those of the two arsenicals prepared by reaction of DMA(V) with either thiosulfate plus disulfite or hydrogen sulfide or sodium sulfide plus sulfuric acid. The faster and slower eluting products on a gel filtration column were assigned as dimethyldithioarsinic acid (dimethylarsinodithioic acid) (DMTA(V)) and dimethylthioarsinous acid (DMTA(III)) from mass spectrometric data at m/z = 170 and 138 by electrospray ionization mass spectrometry with negative and positive ion modes, respectively. They were prepared selectively by reacting DMA(V) with hydrogen sulfide or sodium sulfide plus sulfuric acid under different reaction conditions. DMA(III) but not DMA(V) was transformed to DMTA(III) and DMTA(V) in the presence of sodium sulfide in vitro, suggesting that DMA(V) is reduced to DMA(III) with hydrogen sulfide, thiolated to DMTA(III), and then further thiolated oxidatively to DMTA(V). Metabolically, it is assumed that DMA(III) is transformed to DMTA(III) in the presence of sulfide ions, and then, DMTA(III) is oxidatively thiolated to DMTA(V). As the chemical species produced by reduction with the Reay and Asher method are DMTA(III) and DMTA(V), and different from DMA(III), the studies carried out with DMA(III) with the Reay and Asher method have to be reexamined.

P-Hydroxyphenylacetate decarboxylase from Clostridium difficile. A novel glycyl radical enzyme catalysing the formation of p-cresol.

The human pathogenic bacterium Clostridium difficile is a versatile organism concerning its ability to ferment amino acids. The formation of p-cresol as the main fermentation product of tyrosine by C. difficile is unique among clostridial species. The enzyme responsible for p-cresol formation is p-hydroxyphenylacetate decarboxylase. The enzyme was purified from C. difficile strain DMSZ 1296(T) and initially characterized. The N-terminal amino-acid sequence was 100% identical to an open reading frame in the unfinished genome of C. difficile strain 630. The ORF encoded a protein of the same size as the purified decarboxylase and was very similar to pyruvate formate-lyase-like proteins from Escherichia coli and Archaeoglobus fulgidus. The enzyme decarboxylated p-hydroxyphenylacetate (K(m) = 2.8 mM) and 3,4-dihydroxyphenylacetate (K(m) = 0.5 mM). It was competitively inhibited by the substrate analogues p-hydroxyphenylacetylamide and p-hydroxymandelate with K(i) values of 0.7 mM and 0.48 mM, respectively. The protein was readily and irreversibly inactivated by molecular oxygen. Although the purified enzyme was active in the presence of sodium sulfide, there are some indications for an as yet unidentified low molecular mass cofactor that is required for catalytic activity in vivo. Based on the identification of p-hydroxyphenylacetate decarboxylase as a novel glycyl radical enzyme and the substrate specificity of the enzyme, a catalytic mechanism involving ketyl radicals as intermediates is proposed.

Photosynthetic gas exchange and accumulation of phytotoxins in mangrove seedlings in response to soil physico-chemical characteristics associated with waterlogging.

We evaluated photosynthetic gas exchange and the accumulation of iron, manganese and sulfur in seedlings of five mangrove species (Aegiceras corniculatum (L.) Blanco, Avicennia marina (Forsk.) Vierh., Bruguiera gymnorrhiza (L.) Lamk., Hibiscus tiliaceus L. and Rhizophora stylosa Griff.) growing under anoxic soil conditions at low irradiance. Seedlings of the viviparous mangroves showed no significant responses to root anoxia. The presence of ferrous sulfate or manganous sulfate had a smaller effect on CO(2) assimilation, transpiration rate and stomatal behavior than the presence of sodium sulfide. Sodium sulfide inhibited photosynthetic gas exchange and caused complete stomatal closure in all species. Stomatal closure was probably the result of the damaging effect of sulfide ions on root cell membranes. Some leaf epinasty and wilting were also observed in response to the Na(2)S treatment in all species. A combination of FeSO(4), MnSO(4) and Na(2)S had a smaller effect on photosynthesis than Na(2)S alone, especially for Avicennia marina and Rhizophora stylosa seedlings, which maintained appreciable rates of CO(2) assimilation (2.49 and 3.84 &mgr;mol m(-2) s(-1), respectively) in the presence of all three phytotoxins. Roots of phytotoxin-treated seedlings of all species accumulated significant amounts of the corresponding toxin compared with roots of the control plants. The FeSO(4) or MnSO(4) treatments had no effect on foliar concentrations of iron or manganese, whereas the Na(2)S treatment resulted in an accumulation of S in the leaves of all species. Interactions between Fe(2+) and Mn(2+) and sulfide in the culture medium appeared to reduce their uptake by the seedlings. We conclude that high concentrations of sulfides in mangrove sediments may adversely affect both growth and survival of mangrove seedlings at low irradiances.

Detoxification of environmental sulfide to sulfane sulfur in the intertidal sipunculid Phascolosoma arcuatum

The capability of Phascolosoma arcuatum to detoxify sulfide in anaerobic conditions was examined. Sulfane sulfur, which underwent cold cyanolysis, was the major excretory end product of sulfide detoxification during anoxia. Thiosulfate was not excreted into the external medium. Instead, it was absorbed by P. arcuatum and its absorption was stimulated by the presence of sodium sulfide (Na2S) in the incubation medium. The effective formation and excretion of sulfane sulfur by P.␣arcuatum required the presence of both Na2S and sodium thiosulfate (Na2S2O3). Results obtained indicate that rhodanese might be involved in sulfide detoxification in this sipunculid. Rhodanese could act as a catalyst in the transfer of sulfur atoms from thiosulfate to HS−. The body wall and the introvert were the main sites of sulfide detoxification. However, it is unlikely that epibiotic bacteria associated with the outside surface of the worm were involved in the detoxification process. A time-course study on the contents of thiosulfate and sulfane sulfur in the body wall of P. arcuatum incubated anaerobically in the presence of Na2S + Na2S2O3 verified that thiosulfate absorbed was utilized to detoxify sulfide to sulfane sulfur.

Hot Alkali Refining of Cellulosic Pulps in the Presence of Sodium Sulfide

Abstract Cotton linter pulp and paper pulp were subjected to hot refining with potassium and sodium hydroxide in the presence of sodium sulfide at concentrations of 5% and 20%. The resulting changes in their chemical, physical, and submicroscopic properties as well as their mercerization depth were studied. The addition of sodium sulfide during hot sodium or potassium hydroxide refining of the pulps resulted in a small increase in α-cellulose content of the cotton linters. Remarkable increase was observed in the case of the paper pulp as well as in the resulting decrystallization, and it increased the heterogeneity of the macromolecular structure of both pulps. This led to an increase in the swelling ability of the fibers as revealed from the results of water retention value (WRV), liquor retention value (LRV), and sodium hydroxide retention value (NaOH RV). The addition of sodium sulfide to sodium or potassium hydroxide during hot refining of the cotton linters or to sodium hydroxide during refining of t...