Showing papers on "Sodium sulfite published in 2020"

A chemiluminescence reaction consisting of manganese(IV), sodium sulfite, and sulfur- and nitrogen-doped carbon quantum dots, and its application for the determination of oxytetracycline.

Abstract: Sulfur- and nitrogen-doped carbon quantum dots (S,N-CQDs) were prepared by a solid-phase hydrothermal method from cysteine and citric acid and characterized by transmission electron microscopy, energy-dispersive X-ray spectroscopy, and FTIR spectroscopy. These QDs were exploited as enhancers to amplify the chemiluminescence (CL) of manganese(IV)-sodium sulfite reaction. S,N-CQDs exceptionally enhanced the CL intensity of this system, around 900-fold. This effect was attributed to the energy transfer from SO2*, produced by reaction of Mn(IV) with SO32−, to S,N-CQDs. The maximum wavelength of CL emission was 480 nm, which confirmed that the final emitting species was S,N-CQDs. After optimization of reaction conditions, the analytical applicability of S,N-CQD-Mn(IV)-SO32− CL system was studied. In the presence of oxytetracycline, the CL intensity was significantly diminished. A linear relationship was observed between CL signal and the logarithm of oxytetracycline concentration in the range of 0.075–3.0 μM with a detection limit of 25 nM. This CL assay for oxytetracycline was used for analysis of spiked milk and water samples.

Sodium sulfite as an oxygen scavenger for the corrosion control of mild steel in petroleum refinery wastewater: optimization, mathematical modeling, surface morphology and reaction kinetics studies

Abstract: Corrosion protection of mild steel in simulated refinery wastewater solution (2 wt% MgCl2) by sodium sulfite, as oxygen scavenger inhibitor type, was studied at different temperatures, inhibitor concentrations, rotational velocities and exposure times using weight loss and electrochemical techniques. Oxygen concentrations were also monitored at initial and final conditions. The corrosion inhibition process was optimized by 24 full factorial experimental designs. Optimum conditions of minimum corrosion rate were 40 °C, 40 ppm, 1250 rpm, and 6 h for temperature, inhibitor concentration, rotational velocity, and exposure time. Oxygen levels were reduced by the addition of the scavenger. The amount of oxygen reacted and removed during the corrosion process was evaluated and mathematical relationships were obtained. Electrochemical measurements showed that the corrosion potential shifted to the more active direction and corrosion current decreased with the addition of scavenger. Surface morphology investigations proved that the addition of SS prevents the steel surface damages.

Energy-Saving Cathodic Hydrogen Production Enabled by Anodic Oxidation of Aqueous Sodium Sulfite Solutions

Abstract: The potential energy of SO2 is wasted in the process of converting Na2SO3 to Na2SO4 via air oxidation during conventional treatment of SO2-contaminated air Considering that the oxidation of Na2SO3

Redox and pH Dual-Responsive Emulsion Using Ferrocenecarboxylic Acid and N,N-Dimethyldodecylamine.

Abstract: The derivatives of ferrocene with redox properties are widely used. Some studies have used complex synthesis processes to obtain surfactants with redox properties. In order to simplify the synthesis process, FA-DMDA-Ox, a surfactant with redox and pH dual responses, was prepared by simple electrostatic interaction between ferrocenecarboxylic acid (FA) and N,N-dimethyldodecylamine (DMDA). A stable oil-in-water emulsion was prepared by using FA-DMDA-Ox at 25 °C. When sodium sulfite was added to the emulsion, the emulsion was demulsified. This was due to the oxidized ferrocene group that was reduced from the charged hydrophilic state to the uncharged hydrophobic state, which destroyed the original surface activity. In addition, when added HCl or NaOH to the emulsion changed pH, demulsification was caused by the dissociation of FA-DMDA-Ox.

Gold Leaching Using Thiourea from Uranium Tailing Material, Gabal El-Missikat, Central Eastern Desert, Egypt

Abstract: The objective of this study was to investigate thiourea leaching of gold present in the uranium tailings. Sulfuric acid treatment for raw material is important in order to dissolve uranium as well as to remove easily leachable metals. The acidic thiourea solution was proposed as a non-toxic possible alternative process route to cyanide in gold dissolution. The acidic system of thiourea-sodium sulfite was studied in the gold dissolution process. The presence of sodium sulfite can significantly reduce thiourea decomposition, accelerate the gold dissolution process, decrease the leaching time, and decrease the activation energy of gold dissolution. The activation energy for gold dissolution was evaluated. The activation energy solution with sodium sulfite is 7.62 kJ mol−1 which is much lower than 9.32 kJ mol−1 in the absence of sodium sulfite. Low activation energy confirms the surface reaction dissolution mechanism. This method demonstrates the possibility of extracting gold directly from low-grade ores without any physical or chemical pre-concentration method with a more environmentally friendly process.

Food Additives (Hypochlorous Acid Water, Sodium Metabisulfite, and Sodium Sulfite) Strongly Affect the Chemical and Biological Properties of Vitamin B12 in Aqueous Solution.

Abstract: Food additives, such as hypochlorous acid water, sodium metabisulfite, and sodium sulfite, strongly affect the chemical and biological properties of vitamin B12 (cyanocobalamin) in aqueous solution...

Mechanism analysis of toxicity of sodium sulfite to human hepatocytes L02

Abstract: Food additives are widely used in various food products to preserve the taste, color, and other qualities However, if they are used improperly or exceed the standard, they will cause damage to the human body Sulfite is a commonly used food additive to prevent oxidation from deteriorating the nutrients in foods, it has been widely used as a bleaching agent in the food industry for a long time In this study, human hepatocytes L02 cells were used as a model cell line to evaluate the toxicity of sodium sulfite The cell morphology and cell proliferation were affected by sodium sulfite treatment, and apoptosis was detected Transcriptome sequencing showed 97 differentially expressed genes (DEGs) between the experimental group (IC50) and the control group (MOCK), and 27 differentially expressed genes related to cell apoptosis, metabolism and inflammation were selected for validation by qPCR Among them, 13 significantly upregulated genes and 14 significantly downregulated genes were identified by qPCR The results showed that with increase of sodium sulfite concentration, the morphology of L02 changed, cell proliferation and activity were inhibited, and sodium sulfite caused apoptosis in a concentration- and time-dependent manner The resulting toxic mechanism inhibits proliferation, damages the mitochondrial integrity, and promotes apoptosis

Effects of Potassium Propyl Xanthate Collector and Sodium Sulfite Depressant on the Floatability of Chalcopyrite in Seawater and KCl Solutions

Abstract: This study demonstrates the effects of a potassium propyl xanthate (PPX) collector and sodium sulfite (Na2SO3) depressant on pure chalcopyrite in synthetic seawater (SSW) and potassium chloride (KCl) solutions. SSW solutions with 35 g/L of salt and 0.01-M KCl were used for microflotation and zeta potential tests. Particles sized between 200# and 100# (75–150 µm) were used, and the pH was between 8.0 and 8.5. The surface of the mineral and its interaction with the collector were characterized using Raman spectrometry. The zeta potential of the chalcopyrite was measured in KCl solution at a pH range of 3–12 using the collector and depressant at a monodispersed particle size of 635# (20 µm). The results indicate that the floatability of chalcopyrite is not affected by the presence of PPX collectors in SSW solutions. SSW provides better recoveries than KCl solutions with values of 91.42% and 88.15%, respectively. The Na2SO3 depressant does not hinder the mineral floatability throughout the entire concentration range used; however, special care must be taken when adjusting the pH range to avoid increasing the zeta potential.

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.

Study on dissolution and recovery of waste wool by sodium sulfide system

Abstract: In this research, keratin was extracted from the waste wool fiber using sodium sulfite as dissolving agent. The reaction results showed that the optimum conditions were as follows: the dosage of so...

Optimization of Sulfonated Chemi-Mechanical Pulping of Palm Oil Empty Fruit Bunch Using Response Surface Methodology

Abstract: In order to optimize the sulfonated chemi-mechanical pulping of palm oil empty fruit bunch, the response surface methodology was employed. It was intended to determine the optimum level of sodium sulfite dosage, sodium hydroxide dosage, maximum cooking temperature, and cooking time at the sulfonation stage, and their influences on paper sheets properties were analyzed. An optimum compromise was obtained, and the sodium sulfite dosage, sodium hydroxide dosage, maximum temperature, and cooking time were 18%, 4%, 155 °C, and 100 min, respectively. The density, bursting strength index, tensile strength index, and tearing strength index were 0.5622 g/cm3, 2.60 kPa·m2/g, 45.01 N·m/g, and 7.53 mN·m2/g, respectively.

Study of the Toxicological Characteristics of Water-soluble Surface-active Substances Obtained Based on Phenol, Formaldehyde and Sodium Sulphite

Abstract: The object of research is the products of the condensation reaction of phenol, formaldehyde and sodium sulfite in an aqueous medium, in order to obtain water-soluble non-toxic products based on it, which can be proposed for use as surfactants. In the course of the study, the effect of the reaction conditions (ratio of components, temperature and process time) on the quality of the products obtained and their toxicological characteristics are studied. The optimal ratio of the starting reagents phenol: formaldehyde: sodium sulfite: water is selected, which allows to obtain a product with surface-active properties and which contains substances that can be harmful to health. It is recommended that the condensation process be carried out within 1 hour, the optimum reaction temperature is selected at 130 °C. The qualitative characteristics of the obtained product allow to recommend its use as an anionic surfactant. For this, the symptomatic and toxicological properties of the newly developed surfactant, the product of the condensation of phenol, formaldehyde and sodium sulfite in an aqueous medium, are studied. Based on the studies, it is found that with the introduction of such surfactants into the stomach of experimental white rats-females, their slightly irritating effect on the mucous membranes and skin is observed. According to the mortality criterion, with a single oral administration (LD50), the harmful effects of the substance on rats are not noted. According to the research results, the product can be attributed to class IV hazard (low hazard substances) according to GOST 12.1.007.According to toxicological findings, the resulting product can be recommended for use as a textile auxiliary substance, in the technological operations of bleaching, dyeing and printing of fabrics in contact with human skin, as well as additives to concrete mixtures used in the construction industry and other industries

DOAS Calibration Technique for SO2 Emission Measurement Based on H2SO4 and Na2SO3 Reaction

Abstract: The coal used as a primary fuel in an Indonesian power plant produces sulfur dioxide emission from its burning process. Several testing and monitoring methods developed, from laboratory analysis, CEMs based instrument, and absorption spectroscopy method developed for this purpose. Differential Optical Absorption Spectroscopy (DOAS) method based on Lambert-Beer law used as emission quantification. DOAS instrumentation developed in this research to measure sulfur dioxide as one of the emission parameters. Sulfur dioxide generated from the reaction between the sulfuric acid and dilute sodium sulfite. CCD spectrometer used to measure sulfur dioxide spectrum intensity at 260 to 350 nm absorption cross-section. There is a high correlation between sulfur dioxide gas produced by that reaction to spectrum intensity, with coefficient determination (r2) 0.9783, 0.9822, 0.9866, 0.9928 or coefficient correlation (r) 0.989, 0.991, 0.993, and 0.996 from lowest range concentration to highest range concentration. Precision analysis from gas calibration standard using Horwitz ratio indicates instrument setup precise enough with 0.504 Horwitz ratio, according to its acceptable range. The suspended particulate matter may interfere with UV penetration into CCD detector in emission simulation test using gasoline generator exhaust that causes 2.5 times deviation error between typical 800 ppm concentrated sulfur dioxide from chemical reaction and gasoline generator exhaust.

Dissolution of Silver and Gold with Sodium Hypochlorite and Hydrochloric Acid in Refractory Minerals (Mangano-Argentiferous)

Abstract: The present study examined a process for precious metal recovery (silver and gold) from difficult minerals which exhibit refractory characteristics to cyanidation and ammonium thiosulfate leaching (low extraction and high consumption of leaching agent). It is well known that mangano-argentiferous minerals are mainly composed of manganese, silver, gold, and iron. In this research, a mineral sample from Monte del Favor mine, located in Hostotipaquillo, Jalisco, Mexico, was physically and chemically characterized by X-ray powder diffraction (XRPD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), fire assay, and atomic absorption spectroscopy (AAS). Two-stage leaching was carried out: first to eliminate manganese from the sample using sodium sulfite (Na2SO3) as a reductive reagent and sulfuric acid (H2SO4) and a second stage to dissolve silver and gold with sodium hypochlorite (NaClO) and hydrochloric acid (HCl); the results show extraction around 96% for Mn and 98.73% and 83% of Ag and Au, respectively. The usefulness of high acidity and Na2SO3 to obtain good results in Mn and Ag leaching is discussed along with the roles that HCl and NaClO play in the dissolution of Ag and Au values.

Inhibiting oxidation and enhancing absorption characteristics of sodium sulfite for SO2 removal from the non-ferrous smelting flue gas

Abstract: In this work, we investigated the absorption characteristics of SO2 and the effect of inhibitors on the desulfurization performances of Na2SO3. The results showed that the NO2 had a competitive effect with SO2 on SO3 which resulted in a significant decrease in the absorption capacity of SO2. O2 in the flue gas could decrease the absorption capacity of SO2 due to the oxidation of Na2SO3. Besides, Na2S2O3 had more excellent inhibiting effect on the oxidation of SO3; the inhibition mechanism is understood on the basis of the free radical chain reaction, whereby S2O3 combined with the sulfite free radical to form an inert substance, thus, quenching the reaction of free radical with the dissolved oxygen and invariably inhibiting the oxidation of SO3. Furthermore, the intrinsic and the apparent oxidation kinetics of Na2SO3 oxidation process with Na2S2O3 were investigated to explain the relationships between consumption rates of SO3 and the absorption capacities of SO2 under different components in flue gas and absorption solution.

Heavy metal stabilizing chelating agent, aqueous solution thereof and preparation methods thereof

Abstract: The invention provides a heavy metal stabilizing chelating agent, an aqueous solution thereof and a preparation method thereof. The heavy metal stabilizing chelating agent comprises dithiocarbamate; ferrous sulfate and/or ferrous chloride; organic acid which is selected from one or more of citric acid, malic acid, lactic acid and tartaric acid; sodium thiosulfate and/or sodium sulfide; and disodium hydrogen phosphate and/or sodium dihydrogen phosphate, and optionally sodium sulfite. The heavy metal stabilizing chelating agent can be used for treating waste incineration fly ash, water treatmentsludge containing heavy metals and other substances containing heavy metals, can form stable components with various heavy metals to prevent environmental migration and diffusion of the heavy metalsand prevent leaching pollution under natural conditions, and has a good heavy metal removal effect and high stabilizing efficiency.

Preparation method of high-nickel positive electrode material with improved water washing

Abstract: The invention is suitable for the field of lithium ion battery positive electrode materials, and provides a preparation method of a high-nickel positive electrode material with improved water washing.The method comprises the steps of primary sintering, water washing and secondary sintering. A detergent for water washing is an aqueous solution containing an additive, and the additive is at least one of acetic acid, hydrochloric acid, boric acid, carbamide, cobalt sulfate, sodium carbonate, sodium bicarbonate, sodium sulfite and disodium hydrogen phosphate. The additive can be used for effectively inhibiting the structural lithium from being separated in a water washing process. The structure of the material is protected while the content of the residual lithium on the surface is reduced, and the residual additive on the surface of the material can further react with the residual lithium removed in the secondary sintering process, so that the purpose of removing the residual lithium forthe second time is achieved, and the capacity and the cycle performance of the high-nickel positive electrode material are effectively improved.

Flue gas desulfurization system

Abstract: A flue gas desulfurization system belongs to the field of chemical engineering. According to the method, sodium alkali is adopted as an absorbent byproduct sulfate, the purity of a main product is controllable, typical byproducts such as sodium sulfate, sodium sulfite and sodium metabisulfite belong to a large number of commodities in the market and easily enter the commodity market, no solid waste or waste liquid is generated, and the environmental protection benefit is good. Through reasonable process layout, sodium sulfite can be directly produced by intermittently bypassing the evaporativecrystallization system, 20%-50% of steam consumption can be saved under the same working medium, meanwhile, the novel evaporative crystallizer is adopted, the operation flexibility of the evaporativecrystallization system is improved, and the industrial problem that the evaporative crystallization system is frequently started and stopped and is high in energy consumption is solved.

Effect of “Sodium Sulfite–Ascorbic Acid” Complex Antioxidant Additive on the Composition, Structure and Semiconducting Properties of PbSe Film

Abstract: Comparative experimental data, using dynamic light scattering methods, scanning electron and atomic force microscopy, on the composition, crystal structure, semiconductor and photoelectric properties of PbSe films deposited at the presence of sodium sulfite Na2SO3 and “sodium sulfite–ascorbic acid” complex antioxidant additive are presented. Significant changes in morphology, elemental and phase composition, the period of the crystal lattice of PbSe films been synthesized in the presence of Na2SO3 and Na2SO3 + C6H8O6 anti-oxidants before and after their thermoactivation at 653 K are found. It is shown that the introduction of a complex additive in comparison with Na2SO3 increases the homogeneity of the particles forming the layer, decreases the microstresses in it, reduces the value of thermal band gap from 0.349 to 0.308 eV, and increases the volt-watt sensitivity of the films by 28–30%.

System for producing sodium metabisulfite

Abstract: The utility model provides a system for producing sodium metabisulfite, and belongs to the field of chemical engineering. The method comprises the following steps: sulfur dioxide-containing gas sequentially passes through a first reactor, a second reactor and a third reactor, a supersaturated sodium sulfite solution sequentially passes through the third reactor, the second reactor and the first reactor, and a large amount of sodium pyrosulfite is generated in the first reactor; sodium sulfite complete reaction, when the reaction endpoint is reached, crystal mush containing sodium pyrosulfite is extracted from the first reactor and sent to an elutriation tank, coarse crystal mush enters a centrifugal machine to be separated, sodium sulfite mush is generated by adding sodium carbonate into centrifugal mother liquor and sent to a third reactor, and centrifugally separated solid wet materials are sent to a drying machine to be dried and then packaged into a sodium pyrosulfite product; tailgas generated by drying is discharged after being subjected to alkali washing and dust removal through a tail gas tower, and washing liquid generated by tail gas washing is sent to an alkali preparation tank and returns to the reactor. The sodium metabisulfite prepared by the device is good in quality, novel in technological process and low in energy consumption, and has wide popularization and use values.

Multi-layer film for packaging food and process for preparing the same

Abstract: The present invention relates to a multilayer film for food packaging and a manufacturing method thereof. More specifically, the multilayer film comprises an outer layer, an intermediate layer, and an inner layer. The outer layer contains polyamide, polyethylene terephthalate, and calcium carbonate. The intermediate layer contains linear low-density polyethylene (LLDPE), titanium dioxide (TiO_2), ethylene vinyl alcohol (EVOH), and sodium sulfite. The inner layer contains polyolefin, ethylenediaminetetraacetic acid (EDTA), calcium lactate, metal stearic acid, a sodium-based compound, and an antifungal agent. The multilayer film for food packaging of the present invention absorbs oxygen and can remove not only oxygen penetrating from the outside but also oxygen remaining inside the packaging and oxygen dissolved in the contents, thereby preventing chemical oxidation due to oxygen of the contents and preserving quality. Thus, the multilayer film can increase the shelf life, remove odors that occur during vacuum packaging, and have excellent antibacterial effects, which can suppress the growth of microorganisms.

Maintenance and repair agent for slewing bearing and preparation method thereof

Abstract: The invention discloses a maintenance and repair agent for a slewing bearing and a preparation method thereof. The maintenance and repair agent is prepared from ethylene glycol, calcium chloride, glycerol, sodium sulfite, hydrochloric acid, methylacrylic acid, aluminum polychlorid, calcium silicate, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium chloride, sodium molybdate, triethanolamine, hexamethylene tetramine, citric acid and oxirene. The maintenance and repair agent for the slewing bearing can efficiently repair the rusted slewing bearing, and greatly improves rust resistance, freezing resistance and corrosion resistance of the surface of the slewing bearing. Meanwhile, the preparation method for the maintenance and repair agent for the slewing bearing is simple andclear, is low in cost, and has extremely good practicability and economic benefits.

Process for removing SO2 from flue gases using liquid sorbent injection

Abstract: Finely atomized alkaline sorbent salt solutions are injected into a hot flue gas stream to remove SO2. Flash evaporation of the droplets produces very fine dried sorbent particles, which react efficiently with SO2 in the flue gas. The liquid sorbent may be sodium carbonate, sodium hydroxide, sodium sulfite, potassium carbonate, potassium hydroxide or the like. In a coal-fired boiler, the liquid sorbent may be injected after the economizer section, where the flue gas temperature is below 850° F., and upstream of a particulate collection device. The dried sorbent particles react with SO2 and then are removed from the flue gas stream in the particulate collection device, producing a cleaned flue gas stream.