NaHSO3 Solution Research Articles

Corrosion Resistance Comparison of High Manganese Steel in 0.01mol/L NaHSO3 Solution and 3.5wt.% NaCl Solution

Corrosion Resistance Comparison of High Manganese Steel in 0.01mol/L NaHSO3 Solution and 3.5wt.% NaCl Solution

Corrosion behavior of AlCoCrFeNi2.1 eutectic high-entropy alloy in Cl--containing solution

In this paper, we investigated the corrosion behavior of the AlCoCrFeNi2.1 eutectic high-entropy alloy in 3.5 wt% NaCl solution and 3.5 wt% NaCl + 0.01 mol/L NaHSO3 solution at different temperatures by electrochemical testing, XPS and SEM/EDS. The findings indicate that the AlCoCrFeNi2.1 eutectic high-entropy alloy can be passivated in 3.5 wt% NaCl solution at different temperatures, with the passive film dominated by metal oxides. The component proportions in the passive film change with temperature, with pitting corrosion occurring at the phase rich in Al-Ni as the primary form of corrosion. However, it cannot be passivated in 3.5 wt% NaCl + 0.01 mol/L NaHSO3 solution at any temperatures. Additionally, the surface of the corrosion product film mainly consists of metal hydroxide on the surface, while the proportion of components in the corrosion product film varies with temperature. Furthermore, the corrosion is caused by the dissolution of the Al-Ni-rich phase. The AlCoCrFeNi2.1 eutectic high-entropy alloy does not demonstrate adequate anti-corrosion property in Cl--containing acid Solution.

Corrosion Mechanism and the Effect of Corrosion Time on Mechanical Behavior of 5083/6005A Welded Joints in a NaCl and NaHSO3 Mixed Solution

The effect of corrosion time on the mechanical behavior of 5083/6005A welded joints in a 3.5% NaCl + 0.01 mol/L NaHSO3 solution was evaluated via scanning electron microscopy (SEM), polarization curve analysis, and X-ray photoelectron spectroscopy (XPS). The prediction model of fatigue life after corrosion was established based on the experimental results and the theory of fracture mechanics, and the formula for the effect of corrosion time on lifespan was determined. The results show that with increasing corrosion time, the corrosion of the sample becomes increasingly severe, and the elongation and fatigue life of the 5083/6005A welded joints decrease significantly. The corrosion resistance of the 5083/6005A welded joints decreases with increasing corrosion time because the corrosive medium promotes the destruction of the oxide film and thereby reduces the corrosion resistance. The corrosion products of the 5083/6005A welded joints are Al(OH)3 and AlCl3.

Rapid Reduction and Recovery of Au(III) in Water by Hollow Polym‐phenylenediamine Nanospheres

AbstractTo quickly and efficiently recover precious metal gold from electronic waste products, we synthesized a novel hollow polym‐phenylenediamine (PmPD) nanosphere using the sacrificial template method and applied this materials to reduce and recover Au(III) in an aqueous solution. Experimental results show that the as‐prepared hollow PmPD has high selectivity and treatment capacity for Au(III), and can selectively reduce Au(III) from mixture metals solutions, including Cu2+, Zn2+, Ni2+, Cd2+, and Au(III) mixed solutions. Under room temperature and solution pH 4.0, the maximum treatment capacity of hollow PmPD for Au(III) reaches 1185.18 mg/g in 10 min of equilibrium time. The reduction ability of hollow PmPD remains stable in a pH range of 1.0 to 10.0 and under an ambient temperature ranging from 0 °C to 50 °C. Hollow PmPD can be regenerated via simple NaHSO3 solution washing, and its performance remains stable after repeated recycling. The satisfactory results obtained in treating the computer CPU leaching solution suggest that the hollow PmPD has broad application prospects in recovering gold from e‐waste.

Extraction and purification of 2-hydroxymuconic semialdehyde accumulated in phenol degradation by Pseudomonas stutzeri N2

2-Hydroxymuconic semialdehyde (2-HMS) is a useful intermediate in organic synthesis, but there are few reports for its preparation. 2-HMS accumulates in phenol-containing wastewater treated with Pseudomonas stutzeri N2. This work has studied the extraction of 2-HMS so that the phenolic wastes of high concentration may be used to produce 2-HMS. When 4.25 mmol/L phenol was degraded by Pseudomonas stutzeri N2, the accumulated 2-HMS can reach 3.79 ± 0.08 mmol/L within 30 h. A saturated solution of NaHSO3 was added into the 2-HMS culture, and white rod-like precipitates formed gradually. Through SEM, XRD and FT-IR, the precipitates were identified as monoclinic hexagonal crystals of α-hydroxy sulfonate sodium with high purity. In the presence of NaOH, α-hydroxy sulfonate sodium could be reduced to the desired 2-HMS product. The optimized conditions were characterized to be 3 mol/L NaOH solution, 5 min and 50 °C. The conversion rate of α-hydroxy sulfonate sodium was up to 87.3 ± 0.2%, and 0.42 ± 0.02 mmol/L 2-HMS were obtained.

Adsorption Properties of Au(III) and Cu(II) from Aqueous Solution Using Chemically Treated Sheep Wool

Au(III) and Cu(II) adsorption from aqueous solution were carried out using sheep wools with chemical treatments, by NaOH, Na2S, NaHSO3, and NaBH4 aqueous solution. The fibrous wool was transformed into a film like structures after the chemical treatment using Na2S. The sheep wool and the chemically treated sheep wool adsorbed selectively Au(III) from Au-Cu binary aqueous solution and the presence of copper ion had no effect on the Au(III) adsorption. Au(III) adsorbed substantially at low pH range. The kinetic experimental data fitted well with the pseudo-second-order kinetic model and the adsorption amount of Au(III) increased with time and reached a plateau after 12 h. The kinetic analysis suggests that rate determining step of Au adsorption would be chemisorption due to the formation of a monolayer on the wool surface. Sheep wool is a low cost, eco-friendly material, and has a high capacity of adsorption, and could be used as a biosorbent for precious and heavy metals by modification of appropriate chemical treatment.

Corrosion Behavior of Weathering Steel Q450NQR1 and Welded Metal using Flux-Cored Wire in 0.01 mol/L NaHSO3 Solution

Corrosion Behavior of Weathering Steel Q450NQR1 and Welded Metal using Flux-Cored Wire in 0.01 mol/L NaHSO3 Solution

Effective adsorption of Au(III) and Cu(II) by chemically treated sheep wool and the binding mechanism

Abstract Sheep wool as biosorbent materials was chemically modified by NaOH, Na2S, NaHSO3, and NaBH4 solution. The adsorption amounts of Au(III) were increased after the chemical treatment and the adsorption capacity of the chemically treated wool were performed in the following order; Na2S treated wool > NaBH4 treated wool > NaOH treated wool > NaHSO3 treated wool. Furthermore, sheep wool was modified by Na2S at different concentrations (0.002 – 0.1 M). The surface characterization is analyzed by Fourier-transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The appropriate concentration of treatment was determined at 0.02 M and 0.05 M concentrations of Na2S. Sheep wool changed to a sheet-like structure after 0.05 M of Na2S treatment; however, it keeps fiber structure after treatment of 0.02 M of Na2S. The adsorption amounts of Cu(II) were increased after the Na2S treatment and amounts were performed in the following order; 0.05 M of Na2S treated > 0.02 M of Na2S treated > none treated wool. XPS analysis results indicated that the binding of copper ion to the sheep wool is attributed through the oxygen of carboxyl groups of the sheep wool. Gold was bound to the nitrogen of amino and sulfur of the thiol group was confirmed by XPS. Adsorption kinetics fitted well with a pseudo-second-order kinetic model. Langmuir isotherm model more fit with the experimental data than Freundlich isotherm model. In summary, Na2S treated sheep wool to be revealed as an effective low-cost biosorbent for removal of Au(III) and Cu(II).

Effect of aging treatment on microstructure and corrosion behavior of Al-Zn-Mg aluminum alloy in aqueous solutions with different aggressive ions

The microstructure and corrosion behavior of Al-Zn-Mg alloy (namely 7×××) after natural aging treatment (NAT) and artificial aging treatment (AAT) in aqueous NaCl solutions containing different aggressive ions have been investigated in current work. Results of microstructure characterization demonstrate that the aging treatment has a great influence on the grain size and precipitates. The grain size is relatively sizeable and no evident precipitates are observed in alloy after NAT comparable with that after AAT. The electrochemical corrosion behavior of alloy was studied by polarization curve and electrochemical impedance spectroscopy (EIS). The corrosion potential (Ecorr) of the aluminum alloy is more negative in 3.5 wt.% NaCl containing 0.052 wt.% NaHSO3 solution than that in 3.5 wt.% NaCl solutions with or without 0.907 wt.% NaHCO3. Charge transfer resistance (Rct) results reveal that alloy after AAT has an enhancement of corrosion resistance compare with that after NAT. With the immersion time increasing, mostly pitting spreads over the surface of the alloy only in NaCl solution, whereas exfoliation corrosion mainly occurs in NaCl solutions containing NaHSO3 or NaHCO3.

Compositional, thermal and morphological characterization of recycled and modified elastomers for inclusion in commercial cement mixtures

Elastomers are natural or synthetic polymers used in the automotive, mining, mold, assembly and other industries, due to their mechanical resistance in a wide temperature range from 60 °C to 320 °C; however, the waste generated is not disposed of properly, especially in the manufacture of tires, which generates environmental problems like inadequate final disposal, generation of toxic gases and public health problems; Therefore, in order to recycle these wastes, the present investigation modified elastomers superficially in order to produce strong adhesion with inorganic compounds like cement, through oxidation and sulfonation processes. For this purpose, NaOH and KMnO4 solutions were prepared at a concentration of 5% and then impregnated in saturated NaHSO3 solution. Subsequently, the modified elastomer was morphologically characterized by scanning electron microscope, thermogravimetrically by differential scanning calorimeter; compositionally by infrared spectroscopy, Raman spectroscopy, X-ray fluorescence, energy dispersive X-ray analysis and hydrophobic tests using contact angle techniques, in order to establish morphological and chemical compatibility with inorganic compounds. Results evidenced inclusion of functional groups OH, C = O and SO3, the reduction of carbon present in weak bonds and the presence of inorganic components such as potassium, sodium, manganese and sulfur were evident. The scanning electron microscope shows an increase in the roughness and contact surface of the elastomer as a function of the inclusion of polar functional groups by surface chemical treatment. These characteristics are to generate greater inclusion and compatibility of elastomers of an organic nature in inorganic compounds like cement matrices.

Evaluation of Effects of Increasing Molar Substitution of Hydroxypropylene on Physicochemical, Functional and Morphological Properties of Starch from Water Yam (Dioscorea Alata)

Amidst rising demand for modified starch, hydroxypropylated derivatives from water yam, an underutilized tropical botanical source remains unexplored. The objective of this work therefore is to extract starch from water yam, modify same by hydroxypropylation and determine their physicochemical, functional and morphological characteristics. 
 
 Extraction of starch was carried out by blending peeled water yam previously soaked in 0.2%(w/v) NaHSO3 solution and filtering the resulting slurry. The filterate was next suspended in 0.2% NaOH solution, allowed to sediment and the supernatant oven-dried (400C) for 24 hrs. The dried product was subjected to hydroxypropylation (HP) (propylene oxide 4-12%/100g starch) and extent of molar substitution (MS) determined. The native and Hydroxypropylated starch (HPS) were evaluated for physicochemical, functional and morphological characteristics following standard methods. Pasting properties were analysed using Rapid Visco Analyzer (RVA) and elucidation of inherent functional groups was carried out by analyzing the FTIR Spectrum.
 
 Starch yield of 84.2% (dry wt. basis) and molar substitution (0.0024-0.05) of HPS were established. Bulk density increased (0.4988-0.6005g/cm3) with MS. There was significant (p=0.05) increase in the degree of Whiteness (W) (42.4-63.6%). Although granule size reduction was evident (33.88-33.43µm), hydroxypropylation did not affect their morphology. There was decline in concentrations of crude protein (0.18-0.01%), ash (1.35-0.34%) and amylose (44.19-37.48%) as MS rose. In contrast, there was significant (p=0.05) increase in water (1.76-2.66g/g) and oil absorption capacities (0.72-1.42g/g), swelling power (1.54-4.19g/g) and solubility (3.17-5.84g/g) at 500C. Freeze thaw cycles showed marked reduction in syneresis (10.3-1.09%) as MS increased. Peak Viscosity, pasting temperature and peak time of the HPS ranges were 297.83-583.6, 81.9-86.40C, and 4.5-7.0 mins respectively. FTIR band spectra indicated the presence of hydroxypropyl substituent groups in the modified starch.
 
 Hydroxypropylated starch (from water yam) at different molar substitution has been characterised and its properties established with strong potentials for wider applications in food systems.

A Comparison of Sodium Lignosulfonate (SLS) Synthesis from Black Liquor Lignin and Commercial Lignin

Sulphonation of lignin has been considered as a promising step to produce lignosulfonate which may serve as dispersant, flocculant, and surfactant. The aim of present study was to compare the synthesis of sodium lignosulfonate (SLS) from different lignin feedstocks namely commercial lignin and lignin isolated from black liquor (BL) of pulp and paper industry. A novel technique to isolate lignin from BL was introduced with the aid of CO2 and coagulant of alumunium sulfate. The FTIR spectra of BL lignin showed similarity with commercial lignin which indicates that the isolation of BL lignin with the present technique did not alter the chemical structure of lignin. Furthermore, sulphonation of commercial and BL lignin with NaHSO3 solution has been conducted to obtain SLS powder. In general, the FTIR spectra of SLS from commercial and BL lignin were similar to their parent lignin. However, absorption peak which corresponds to SO3 vibration was lightly detected on both samples which indicated the insertion of SO3 functional group into the lignin structure. The ability of SLS to increase the oil mobility for Enhanced Oil Recovery (EOR) was measured from the interfacial tension (IFT). Our results showed that the IFT values of SLS solution from commercial lignin and BL lignin were 0.3759 mN/m and 0.2675 mN/m, respectively. Further formulation of SLS from BL lignin with octanol and PFAD solution may lower the IFT value to 0.0186 mN/m.

Corrosion Behavior of T91 Steel by Salt Spray with 0.1%NaHSO3 Solution

Corrosion Behavior of T91 Steel by Salt Spray with 0.1%NaHSO3 Solution

Surface modification of crumb rubber and its influence on the mechanical properties of rubber-cement concrete

In this paper, a surface modification method was proposed to introduce strong polarity groups to rubber surface to generate a strong chemical bond between the rubber and the cement matrix. Rubber was first oxidized with KMnO4 solution and then sulphonated with NaHSO3 solution. The Fourier transform-infrared (FT-IR) spectra and contact angle measurement showed that the oxidation and sulphonation process introduced a large number of hydrophilic hydroxyl and sulfonate to crumb rubber and decreased the contact angle between rubber surface and water, thus greatly improved the interfacial bonding strength between crumb rubber and cement paste. After the rubber surface modification, the adhesion strength of the rubber and cement paste was increased by 41.1%. It was also found in the mechanical tests that the rubber surface modification was quite useful to enhance the compressive strength and impact strength of rubber-cement concrete. The compressive strength of the concrete with 4% modified rubber powder was 48.7% higher than that with ordinary rubber powder. Based on the results, it is concluded that the surface modification of crumb rubber with KMnO4 and NaHSO3 solutions is an effective method to improve the mechanical properties of rubber-cement concrete.

Some physicochemical and rheological properties of starch isolated from avocado seeds

Seeds from avocado (Persea americana Miller) fruit are a waste byproduct of fruit processing. Starch from avocado seed is a potential alternative starch source. Two different extraction solvents were used to isolate starch from avocado seeds, functional and rheological characteristics measured for these starches, and comparisons made to maize starch. Avocado seed powder was suspended in a solution containing 2mM Tris, 7.5mM NaCl and 80mM NaHSO3 (solvent A) or sodium bisulphite solution (1500ppm SO2, solvent B). Solvent type had no influence (p>0.05) on starch properties. Amylose content was 15–16%. Gelatinization temperature range was 56–74°C, peak temperature was 65.7°C, and transition enthalpy was 11.4–11.6J/g. At 90°C, solubility was 19–20%, swelling power 28–30g water/g starch, and water absorption capacity was 22–24g water/g starch. Pasting properties were initial temperature 72°C; maximum viscosity 380–390 BU; breakdown −2 BU; consistency 200 BU; and setback 198 BU. Avocado seed starch dispersions (5% w/v) were characterized as viscoelastic systems, with G′>G″. Avocado seed starch has potential applications as a thickening and gelling agent in food systems, as a vehicle in pharmaceutical systems and an ingredient in biodegradable polymers for food packaging.

Bisulfite induced chemiluminescence of g-C3N4 nanosheets and enhanced by metal ions.

In this work, a novel chemiluminescence (CL) phenomenon was found: a g-C3N4 nanosheets suspension was mixed with NaHSO3 solution directly to produce luminescence, and the intensity of luminescence could be obviously enhanced by some metal ions, which was distinctly different from the phenomenon that Cu(2+) ions can quench the fluorescence of g-C3N4 nanosheets as reported before.

Effect of Titanium on the Precipitating Behavior of Inclusions and Corrosion Resistance of Niobium Stabilized 409 Ferrite Stainless Steel

In order to investigate the effect of titanium addition on the precipitating behavior of inclusions and corrosion resistance of niobium stabilized ferrite stainless steel, experiments were conducted in a high frequency vacuum induction furnace for smelting titanium and niobium stabilized ferrite stainless steel in argon atmosphere, and the composition, morphologies and size of inclusions in the samples were investigated. Precipitating behavior of the inclusions and intergranular corrosion resistance of the samples were analyzed by CSLM. Corrosion resistance of the steel in 2% NaHSO3 solution was tested by using electrochemistry comprehensive test instrument. The results show that inclusions in the as cast steel mainly are rectangle TiN, TiC, NbC and complex inclusions with TiN or TiC as core packed by NbC, and their size is about 1~5μm. There are a few nearly spherical complex inclusions with Al-Mg-Si-Ti-O as core packed by TiN, TiC, NbC or their complex inclusions. The spherical inclusions become rectangle with the increase of titanium addition, and the quantities of inclusions which size is larger than 5 μm increase. Precipitates increase during heat treated and grain size of the steel becomes a little smaller with the increase of titanium content in the steel. The grain boundary of the steel becomes stabilization and intergranular corrosion resistance enhances with the increase of titanium content in the steel according to the online analysis results. Passivation current density of the steel becomes smaller and passive potential range becomes wider in 2% NaHSO3 solution at 30°C with the increase of titanium content in the steel which indicates corrosion resistance of the steel being enhanced.

Recovery of renewable phenolic fraction from pyrolysis oil

The aim of this work was to develop a separation process for phenolic fraction recovery from various bio-oils, produced by fast pyrolysis process of wood and forest residues in the framework of the EU Project BIOCOUP. Two slightly different schemes were introduced, namely the first one starting with an aqueous extraction of pyrolysis oil and the second one with the simultaneous use of a hydrophobic-polar solvent and anti-solvent in the extraction of bio-oil. In both cases the distribution coefficients of phenolic components between the phases as well as extraction factors for major separation stages are presented. Different aqueous solutions were applied and alkali solution was found to be more efficient in comparison to water or aqueous NaHSO3 solution. From various hydrophobic-polar solvents which had been tested, methyl isobutyl ketone (MIBK) was shown to be the most efficient solvent for extraction of phenolics from bio-oil in combination with 0.1 or 0.5M aqueous NaOH solution, followed by butyl acetate.

Effect of Temperature on Structure and Corrosion Resistance of Oxide Scale on Hot Rolled Strip

Various structure scales at the surface of SS400 hot rolled strip were fabricated by heat treatment processes involving different temperatures. A simulation about the effect of various temperatures on the oxide scale structure during the coiling process was carried out. The structure and corrosion behavior of different oxide scales formed at the surface of hot rolled strip were investigated in sodium bisulfite (NaHSO3) solution by scanning electron microscope (SEM), X-ray diffraction (XRD), polarization curves and electrochemical impedance spectroscopy (EIS). The scale prepared at 550 °C is mainly composed of one layer of Fe3O4 phase. The scales prepared at 600 °C and 700 °C consist of the outer thin Fe2O3 layer and the inner (Fe3O4+Fe particles) layer. The scale prepared at 650 °C is mainly composed of Fe3O4 phase as well as a spot of Fe2O3 phase. The thickness of scale prepared at 650°C is observed to be more homogeneous than that of other scales and the bonding between the scale and substrate is found to be very strong. The experimental results clearly reveal that the hot rolled strip with scale prepared at 650 °C exhibits the most excellent corrosion resisting property in 0.01 mol/L NaHSO3 solution.

The Influence of HSO<sub>3</sub><sup>-</sup> Activity on Electrochemical Characteristics of Copper

The electrochemical behavior of copper in various concentrations of NaHSO3 solution was investigated with linear polarization and cyclic voltametry technique at room temperature. The results showed that the concentration of bisulfite ions has noticeable effects on the behavior of copper. With HSO3 -concentration increasing, the passivity region, ascribed to the formation of absorption layer Cu (HSO3) ads - or Cu (SO4) ads 2-, appearing at the lower potential range in the polarization curve inclined to transform into an active region; whereas another passivity region, due to the appearance of CuO or Cu2O layer on the surface, took place at a higher potential region. The formation and the reduction of CuO or Cu2O were irreversible.