Sulfite Solution Research Articles

Effects of Low-Level Aqueous Hydrogen Sulfide and Other Sulfur Species on Lettuce (Lactuca sativa) Seed Germination

Low concentrations of aqueous hydrogen sulfide (H2S) can stimulate growth of some crops. However, it is not clear whether H2S provides crops with only sulfur and whether other sulfur compounds have similar beneficial effects. Therefore, impacts of solutions of sodium sulfate (Na2SO4), sodium sulfite (Na2SO3), sodium sulfide (Na2S), ferrous sulfide (FeS), and H2S at 0.01–1 mM were assessed on 5-day lettuce seed germination. Results showed that 0.01 mM H2S solution significantly increased lettuce shoot elongation by 40 percent (to 43.6 mm from 31.0 mm in the control), whereas 0.1 mM increased elongation by 24 percent to 38.5 mm. Only a slight 10 percent increase was observed in 0.1 mM Na2SO4, suggesting that ameliorative impact of H2S on plant growth was not a result of providing sulfur nutrient. Other sulfur solutions, however, inhibited lettuce germination and elongation to varying extents, hinting that H2S might work as a signal molecule in regulating plant cellular activities.

Mathematical computation of water quality index of Vea dam in upper east Region of Ghana

The effect of sulfite on barley seedlings was investigated through Chl content, the electron transport activity of the photosystem, and Chl fluorescence. Barley leaves were harvested every 12 hrs during greening periods, and were then treated with a sulfite solution in either light or dark conditions. In both cases, the Chl content decreased in comparison with the control at any greening period. After sulfite treatment in the light, the activity of PS Ⅰ decreased slightly. yet that of PS Ⅱ showed a decrease of about 15%. The values of Fv, qP and qE decreased. however the value of qI increased compared with the control. In addition, the value of qE decreased in leaves greened more than 12 hrs compared with that of the control. This indicates that the photosynthetic complex involved in energy dependent fluorescence quenching is undeveloped in a 12 hrs greened leaf, accordingly, it was a hardly affected by sulfite. After sulfite treatment in the dark, the activities of PS Ⅱ and PS Ⅰ decreased slightly. there was a small change in the value of Fv, qP decreased, and qE and the ratio of qNP/q increased in comparison with the control. As a result, PS Ⅱ and PS Ⅰ were not inhibited, however, the redox of Q_(A) was inhibited, and the excited energy was lost through the nonphotochemical pathway. The effects of sulfite in light or dark conditions were not remarkably different according to the PS Ⅰ and Ⅱ activity measurement method yet were considerably different with the Chl fluorescence quenching analysis method. In both light and dark conditions, the value of qP significantly decreased with sulfite compared to that of the control. This implies that the redox of Q_(A) was inhibited by sulfite in both light and dark conditions.

A comparison of different methods to remove dissolved oxygen: Application to the electrochemical determination of imidacloprid

This study compares different methods for the removal of oxygen from the solution prior to the chronopotentiometric determination of the insecticide imidacloprid on glassy carbon electrode. The research included the application of the chemical method involving addition of sulfite ion, and the physical method of purging the sample with nitrogen stream, as well as their combination. By comparing analytical signals of imidacloprid, chemical method showed almost the same efficiency as conventional physical method, while the best reproducibility was achieved by applying chemical method with addition of the saturated sodium sulfite solution. The method is very simple and can be applied for deoxygenation of the solution prior to the chronopotentiometric analysis. The application of the chemical deoxygenation significantly shortened duration of the chronopotentiometric analysis of imidacloprid from approximately 15 min to 1 min.

Effect of sodium sulfite, carboxylic monomer, and phosphoric acid etching on bonding of tri-n-butylborane initiated resin to human enamel.

The purpose of the present study is evaluation of bonding durability of tri-n-butylborane (TBB) initiated resin without 4-methacryloyloxyethyl trimellitate anhydride (4-META) joined to human enamel. Ground human enamel was bonded with TBB resin under six surface conditions: 1) as ground, 2) primed with Teeth Primer, 3) sodium sulfite solution, 4) 4-META solution, 5) acetone-water, and 6) phosphoric acid etching. Pre- and post-thermocycling bond strengths and change in strength after thermocycling were compared. Etching enamel with 35-45% phosphoric acid enhanced bonding durability between enamel and TBB-initiated resin. Priming with Teeth Primer or 4-META solution improved bond strength between enamel and TBB-initiated resin. Sodium sulfite had little effect on enamel bonding in the present bonding systems.

Anode current on gold in mixed thiosulfate-sulfite electrolytes

The anodic current in individual and mixed thiosulfate-sulfite solutions was studied by means of voltammetry on a fresh gold RDE surface. An unexpected result was obtained: a new additional current maximum appears on the anodic voltammogram in mixed solutions; it is not observed in the individual solutions of sodium thiosulfate and sulfite. The reasons for, and mechanism associated with, this phenomenon require separate and detailed investigation. It is shown that the rate of the anodic process in sulfite solutions is limited by diffusion of discharging particles, while the rate of the anodic process in thiosulfate solutions is limited by slow (in comparison with diffusion) heterogeneous reactions. In mixed solutions, the presence of thiosulfate causes partial passivation of the electrode, while the presence of sulfite causes its partial depassivation. It is stressed that the initial stages of oxygen evolution on gold have opposite effects on anodic currents in sulfite and thiosulfate solutions.

Kinetic Studies on NO2 Absorption into Ammonium Sulfite Solutions

The absorption reactions of NO2 into (NH4)2SO3 solution were investigated in a stirred tank reactor. The kinetic regime of the absorption reaction was identified and the effects of various experimental parameters were studied. The experimental results indicated that the absorption of NO2 into (NH4)2SO3 solution is accompanied by a fast pseudo-first-order reaction. It was found that the NO2 absorption rates were enhanced by the increasing concentration of (NH4)2SO3 but nearly remained constant if the concentration is greater than 0.1 mol/L. The absorption rates also increased with increasing the reaction temperature and the concentration of NO2 in inlet gas, but decreased as the oxygen concentration increased.

Applied Kinetics Aspects of Ferric EDTA Complex Reduction with Metal Powder

Nitrogen and sulfur oxides (NOx and SOx) emitted from fossil-fuel-fired facilities can be simultaneously absorbed into aqueous mixed solutions of sulfite and FeIIL, a ferrous ion coordinated to a ligand L (a chelate compound). Usually, the ligand L represents an anion of ethylenediaminetetraacetic acid (EDTA or edta). Nitrogen oxide (NO) sparingly soluble in water is promptly bound to the [FeII(edta)(H2O)]2– complex to form the [FeII(edta)(NO]2–compound. However, [FeII(edta)(H2O]2– chelate is oxidized to form [FeIII(edta)(H2O)]− by NO, NO2, and O2, normally coexisting in flue gases. Because the ferric complex does not react with NO, the suppression of these undesired oxidation processes is a very important technological problem to be overcome. Thus, in this work, the reduction kinetics of ferric ion by metal was discussed on the basis of the kinetic data regarding the ferric ion reduction in aqueous solutions of [FeIII(edta)(H2O)]− containing such pulverized metals as aluminum, tin, and zinc. The rate exp...

Effects of Different Reagent on the Separation of Starch and Protein in Corn Endosperm

Corn and corn flour were steeped with different chemical reagents ,sulfurous acid (0.1%, 0.2%, 0.1%)、NaOH (0.1%, 0.3%, 0.5%)、alcohol (65%, 75%, 65%)、lactic acid (0.3%, 0.5%, 0.3%)、L - cysteine (0.6%, 1.0%, 1.4%) ,using distilled water as control. The separation of starch and protein in corn endosperm steeped under different reagents were analyzed using the amount of free starch measuring by iodine colorimety.The results show that under the action of different concentration of NaOH、sulfurous acid、lactic acid,the measured value of free starch in both corn and corn flour were increased and were higher than control,with the extending of the soak time and increase of reagent concentration.The effect of NaOH is the best,but when the NaOH concentration was above 0.5%, the amount of free starch began to decline. The starch granules were destroyed by the high concentration of alkali. The effect of Sulfite solution is good also, and the observed value of free starch slightly higher than the lactic acid. The effect of different concentration L-cysteine on corn was almost the same as control,but the effect of separation on corn flour was obviously enhanced and better than sulfurous acid,especially concentration above 1.0%.There was no starch granules out of corn and corn flour by alcohol soaking.

Bimetallic nickel–iron nanoparticles for groundwater decontamination: Effect of groundwater constituents on surface deactivation

The incorporation of catalytic metals on iron nanoparticles to form bimetallic nanoparticles (BNPs) generates a class of highly reactive materials for degrading chlorinated hydrocarbons (e.g., trichloroethylene, TCE) in groundwater. Successful implementation of BNPs to groundwater decontamination relies critically on the stability of surface reactive sites of BNPs in groundwater matrices. This study investigated the effect of common groundwater solutes on TCE reduction with Ni–Fe (with Ni at 2 wt.%) bimetallic nanoparticles (herein denoted as Ni–Fe BNPs). Batch experiments involving pre-exposing the nanoparticles to various groundwater solutions for 24 h followed by reactions with TCE solutions were conducted. The results suggest that the deactivation behavior of Ni–Fe BNPs differs significantly from that of the well-studied Pd–Fe BNPs. Specifically, Ni–Fe BNPs were chemically stable in pure water. Mild reduction in TCE reaction rates were observed for Ni–Fe BNPs pre-exposed to chloride (Cl−), bicarbonate (HCO3−), sulfite (SO32−) and humic acid solutions. Nitrate (NO3−), sulfate (SO42−) and phosphate (HPO42−) may cause moderate to severe deactivation at elevated concentrations (>1 mM). Product analysis and surface chemistry investigations using high-resolution X-ray photoelectron spectroscopy (HR-XPS) reveal that NO3− decreased particle reactivity mainly due to progressive formation of passivating oxides, whereas SO42− and phosphate elicited rapid deactivation as a result of specific poisoning of the surface nickel sites. At similar levels, phosphate is the most potent deactivation agent among the solutes examined in this study. While our findings point out the desirable quality of Ni–Fe nanoparticles, particularly their greater electrochemical stability compared to Pd–Fe BNPs, its susceptibility to chemical poisoning at high levels of complexing ligands is also noted. Groundwater chemistry is therefore an important factor to consider when choosing appropriate material(s) for decontaminating the complex environmental media.

Simulation of blood oxygenation in capillary membrane oxygenators using modified sulfite solution

Blood oxygenation is the main performance characteristic of capillary membrane oxygenators (CMOs). Handling of natural blood in in vitro investigations of CMOs is quite complex and time-consuming. Since the conventional blood analog fluids (e.g. water/glycerol) lack a substance with an affinity to capture oxygen comparable to hemoglobin's affinity, in this study a novel approach using modified sulfite solution is proposed to address this challenge. The solution comprises sodium sulfite as a component, simulating the role of hemoglobin in blood oxygenation. This approach is validated by OTR (oxygen transfer rate) measured using native porcine blood, in two types of commercially available CMOs. Consequently, the number of complicated natural blood investigations in the evolution procedure of newly developed oxygenators would considerably decrease. Moreover, the reassessing of failed devices, in clinics, would be performed more precisely using a modified sulfite solution than simple water/glycerol testing.

Synthesis of sodium allyl sulfonate in an aqueous medium by micellar catalysis with methoxy polyethylene glycol methacrylates

Micellar catalysis with various polyoxyethylated compounds was used to synthesize sodium allyl sulfonate by the reaction of allyl chloride with an aqueous solution of sodium sulfite. It was shown that methoxy polyethylene glycol methacrylates and water soluble polymers based on these compounds are surfactants and can be used to intensify the synthesis of sodium allyl sulfonate, which is of interest in the case of its subsequent application to obtain copolymers with methoxy polyethylene glycol methacrylates.

Characterization and Correction of Temperature Effects on Ru(bpy)<sub>3</sub><sup>2+</sup> Fluorescence Films Used in Dissolved Oxygen Sensor

The spectral characteristic of the fluorescence film used in dissolved oxygen sensor is influenced by temperature. In this paper, we quantitatively studied the temperature effect of the dissolved oxygen sensitive film based on Ru (bpy)32+ complexes. In order to study how it was affected, two experiments were designed. One experiment was carried out when the sensitive membrane was dipped into solution of saturated sodium sulfite, in which case, there was no oxygen interference. The other experiment was implemented when the sensitive film was exposed to air, while the influence of oxygen was constant. In the processes of both experiments, we adjusted the temperature around the sensitive membrane. When the temperature rising from 0°C to 45°C, the fluorescence intensity emitted from the sensitive film was reduced which in the first experiment decreased from 5030counts to 3845counts and in the second experiment from 2314counts to 1407counts. Then a method can correct the temperature effect was proposed. The curve of spectrum at 25°C was supposed to be the standard and spectrums at other temperatures was corrected to be consistent with it. The correction coefficient of every wavelength was got through our calculation. After multiplying the coefficients, fluorescence intensity at different temperatures was approximately equal and the differences caused by temperature were eliminated.

Leaching kinetics of selenium from selenium–tellurium-rich materials in sodium sulfite solutions

The leaching kinetics of selenium from selenium–tellurium-rich materials in sodium sulfite solutions was studied. The morphologies of selenium–tellurium-rich materials are mainly spheroid and columnar bodies and the range of particle size of selenium–tellurium-rich materials is between 17.77 μm and 56.58 μm, which contain 41.73% selenium and 40.96% tellurium. The ranges of experimental elements are 126–315 g/L of sodium sulfite concentration, 100–400 r/min of agitation speed, 23–95 °C of reaction temperature, 7:1–14:1 of liquid–solid ratio and 17.77–56.58 μm of average particle size. The results show that the leaching rate increases with increasing the sodium sulfite concentration, agitation speed, reaction temperature or liquid–solid ratio and the leaching rate decreases with increasing the particle size. The reaction temperature has the significant effects on the selenium leaching rate which increases from 21% to 67% with increasing temperature from 23 °C to 95 °C. The experimental data agree quite well with the Avrami model for leaching, with model parameter of 0.235 and apparent activation energy of 20.847 kJ/mol.

Reaction of (conjugated) deoxynivalenol with sulphur reagents - novel metabolites, toxicity and application

Recently, three novel deoxynivalenol (DON) sulphonates (DONS-1, -2 and -3) formed by transformation of DON with sulphur reagents were discovered. Their structures were elucidated, factors influencing their formation were investigated and their stability was evaluated. The first aim of the present work was to assess the toxicity of the three DONS. The hypothesis was a loss of toxicity of DONS-1 and reduced toxicity of DONS-2 and DONS-3 compared with DON. Three different toxicity tests confirmed this hypothesis, revealing reduction of toxicity by factors of at least 330, 29 and 33 for DONS-1, -2 and -3, respectively. The second objective was to investigate the reaction of DON conjugates with sulphur reagents both in solution and in cereal samples, and to determine the pattern of the formed DONS in DON-contaminated cereals. Reversed phase ultra high performance liquid chromatography-high resolution tandem mass spectrometry demonstrated that also conjugated mycotoxins (DON-3-glucoside, 3-acetyl-DON, 15-acetyl-DON) are converted into DON conjugate sulphonates upon incubation with sodium metabisulphite (SBS) or sodium sulphite in solution. DON conjugate sulphonates of the series 1, 2 and 3 differed in their fragmentation pattern in a similar way as DONS-1, -2 and -3. Treatment of a barley sample contaminated with DON, 3-acetyl-DON and the masked mycotoxin DON-3-glucoside with SBS revealed that the predominantly formed compounds are DONS-3 and DON conjugate sulphonates of the series 3, followed by those of the series 2. Incubation of DON containing maize samples of different moisture contents with 0.5% of SBS or sodium sulphite for 7 days confirmed DONS-3 as main DON transformation product. Both in barley and in maize, SBS and sodium sulphite showed different efficiency for transformation of DON at low moisture contents. These findings provide novel insights into inactivation of DON-contaminated cereals.

Volumetric Mass Transfer Coefficient of SO2 Gas Absorption into Aqueous Sodium Sulphite Solution in Plate Column

The volumetric mass transfer coefficient (KG.a) for SO2 removal from gas mixture into aqueous Na2SO3 solution was studied in a plate column at constant temperature ( 25 , and liquid holdup. The KG.a values were evaluated over ranges of operating independent variables: gas flow rate (QG), SO2 concentration in inlet gas (CSO2, in), and concentration of aqueous Na2SO3 solution (CNa2SO3). The experimental results showed that KG.a decreased with increasing of CSO2, in, increased with increase of QG, and CNa2SO3. The influence of gas flow rate on KG.a is more than the influence of SO2 concentration in inlet gas, and concentration of aqueous Na2SO3 solution respectively. Computer program Statgrhaphics/Experimental design was used to find the linear fitted models of the KG.a in terms of the dimensional and dimensionless of independent operating variables. The QG, CSO2, in, and CNa2SO3 have significant effects on KG.a, while the interactions of them have no significant effects on it, and could be neglected. The R-squared statistic indicates that the model as fitted explains 90.4949% of the variability in KG.a.

Bioconversion of Beetle-Killed Lodgepole Pine Using SPORL: Process Scale-up Design, Lignin Coproduct, and High Solids Fermentation without Detoxification

Mountain pine beetle killed Lodgepole pine (Pinus contorta Douglas ex Loudon) wood chips were pretreated using an acidic sulfite solution of approximately pH = 2.0 at a liquor to wood ratio of 3 and sodium bisulfite loading of 8 wt % on wood. The combined hydrolysis factor (CHF), formulated from reaction kinetics, was used to design a scale-up pretreatment on 2000 g wood chips at a relatively low temperature of 165 °C that reduced furan formation and facilitated high solids saccharification and fermentation. The pretreated solids and liquor were disk milled together to result in a biomass whole slurry of 25% total solids. The whole biomass slurry was directly used to conduct simultaneous enzymatic saccharification and combined fermentation (SSCombF) using a commercial cellulase and Saccharomyces cerevisiae YRH400 without detoxification. A terminal ethanol titer of 47.1 g L–1 with a yield of 306 L (tonne wood)−1, or 72.0% theoretical, was achieved when SSCombF was conducted at an unwashed solids loading of...

Suppressing electroless growth allows cyanide-free electrodeposition of straight separable gold nanowires

Gold cyanide is strongly complexed in solution and works well for the electrochemical synthesis of separable nanowires. Straight single axisymmetric nanowires are significant for many applications, but particularly so for sensors based on nanoelectromechanical systems (NEMS) such as nanoresonators. The toxicity of cyanide solutions makes non-cyanide alternatives desirable. However, electrochemical synthesis of gold nanowires in templates from non-cyanide solutions suffers from serious drawbacks. These include growth-arresting pellet formation, poor length control and defects such as inclusions. Here we present the first electrochemical synthesis of straight, cylindrical, separable gold nanowires from a sulfite solution. We demonstrate a scheme that suppresses electroless particle growth in the weakly-complexed gold in solution. We discuss a mechanism for this scheme, which suggests that this approach has potential for better controlled electrodeposition in separable nanowire synthesis.

Stress in electroplated gold on silicon substrates and its dependence on cathode agitation

The influence of cathode agitation on the residual stress of electroplated gold has been investigated. Using a custom-built plating cell, a periodic, reciprocating motion was applied to silicon substrates that were electroplated with soft gold. A commercially available gold sulfite solution was used to deposit the 0.6μm thick gold films using a current density of 3.0mA/cm2 and a bath temperature of 50°C. By increasing the speed of cathode agitation from 0 to 5cm/s, the magnitude of the compressive stress decreased from −64 to −9MPa. The results suggest that cathode agitation significantly alters the mass transport within the electrolytic cell and can be used as a method of stress control in gold electroplating. This finding is potentially significant for plating applications in microelectronics and microsystems that require precise stress control.

Neutral Sulfite Treatment of Lignocellulosic Pulps

Birch and eucalyptus kraft pulps were treated with sulfite solutions in neutral conditions (pH 7) at 170 °C for 60 min and at 190 °C for 180 min. The pulps were analyzed for kappa number, viscosity, carbohydrate composition, and optical properties. Additionally, UV resonance Raman (UVRR) spectroscopy was applied to collect information on the contents of hexenuronic acid (HexA), lignin, and its phenolic hydroxyl groups. The sulfite treatments resulted in (i) depolymerization and partial dissolution of cellulose, (ii) partial dissolution of xylan and substantial decrease in its HexA content, and (iii) removal of the major part of lignin and increase in its phenolic hydroxyl group content. The extensive removal of HexA and depolymerization of cellulose by neutral sulfite were unexpected phenomena that have not been previously reported. According to their degree of polymerization (DP), the pulps were mainly in the form of microcrystalline cellulose after the more drastic treatments.

Prepared Polymethacrylate-Based Monoliths for the Separation of Cations by Non-Suppressed Capillary Ion Chromatography

This paper describes a novel analytical system for non-suppressed capillary ion chromatography. Methacrylate monolithic columns were prepared from silanized fused-silica capillaries of 320 µm i.d. by in situ polymerization of glycidyl methacrylate and ethylene dimethacrylate in the presence of 1,4-butanediol, 1-propanol and water as the porogen solvents. The introduction of cation-exchange sites was achieved by sulfonating the matrix with sodium sulfite to produce total cation-exchange capacities in the range of 45-105 μequiv/mL for a 25 cm column. The conditions (concentrations of sodium sulfite solution, reacting time and modified flow rate) of sulfonation were optimized. The hydrodynamic and chromatographic performances were estimated. Coupled with a conductivity detector, a capillary ion chromatography system was set up with the prepared column. Finally, the resultant column was used for the separations of five common univalent cations (Li(+), Na(+), NH4(+), K(+) and Cs(+)) using methanesulfonic acid as the eluent and four divalent cations (Mg(2+), Ca(2+), Sr(2+) and Ba(2+)) by non-suppressed capillary ion chromatography; the chromatographic parameters were further researched.