NaCl Acid Research Articles

Understanding the interaction between erosion and corrosion of pipeline steel in acid solution of different pH

The pure corrosion, erosion-corrosion and pure erosion behaviors of X65 pipeline steel in acid NaCl solution of different pH levels (ranging from 1.5 to 5.0) were studied using a rotation disc system, aiming to understand the interaction between erosion and corrosion of pipeline steel operating in acid slurry. The corrosion and erosion-corrosion performances of the steel were electrochemically measured in conjunction with surface characterizations. The pure erosion performance was studied by applying cathodic protection to eliminate the corrosion component. The propagation of the localized erosion-corrosion at different pH levels were probed using wire beam electrode. Results show that pH = 3.5 is a critical value for the transition of cathodic reaction under erosion-corrosion. In the acid fluids of pH < 3.5, the reduction of H+ is the main cathodic reaction, leading to a general erosion-corrosion feature with scattered small pits, which are initiated from the inclusions. Negative erosion-enhanced corrosion (E-C) is found at pH < 3.5 due to the wear of Fe3C networks. The oxygen reduction becomes the main cathodic reaction in the acid slurry of pH ≥ 3.5, resulting in the formation of erosion-corrosion pits and craters. The removal of the rust layer would result in positive E-C performance at pH > 3.5. Significant localized erosion-corrosion would occur at pH ≥ 3.5, where fixed major anodic sites are visualized. Obvious erosion-corrosion pits and craters would form with the occurrence of oxygen reduction. More serious corrosion-enhanced erosion (C-E) prefers to occur at the pitting areas where high macro-cell currents are registered.

Kinetics and Mechanism of Oxidation of Iron (Ii) and Copper (I) by Oxygen in Acid Nacl Solutions at 75°C

Kinetics and Mechanism of Oxidation of Iron (Ii) and Copper (I) by Oxygen in Acid Nacl Solutions at 75°C

Electrochemical behavior and corrosion mechanism of anodized 7B04 aluminum alloy in acid NaCl environments

Electrochemical behavior and corrosion mechanism of anodized 7B04 aluminum alloy under acid NaCl immersion and salt spray tests (pH = 3.5) were studied by morphology observation, electrochemical impedance spectroscopy (EIS), and scanning Kelvin probe (SKP). The influences of exposure conditions and sealing treatment on the properties of anodic film were analyzed. The results showed that the surface Volta potential distribution of 7B04 aluminum alloy tends to be uniform after anodizing and sealing treatment. In the two corrosive environments, the porous layer of both unsealed and sealed anodic film had the self-sealing process and autocatalytic process, which made the porous layer maintain high resistance in long-term tests. The sealing treatment effectively improved the blocking performance of the porous layer, and the fitted resistance value was always greater than 104 Ω·cm2. The corrosion of both unsealed and sealed anodic film samples in the immersion test was more serious than that in the salt spray test, which due to the different interaction modes between the electrolyte and anodic film surface. The results of EIS, SKP, and morphology observation had a good qualitative correlation.

Degradation of oxamic acid using dimensionally stable anodes (DSA) based on a mixture of RuO2 and IrO2 nanoparticles

Dimensionally stable anodes (DSA) have been widely used to degrade organic compounds because these surfaces promote the electrogeneration of active chlorine species in the bulk of the solution, as well as in the vicinity of the anode when NaCl is used as supporting electrolyte. In this work, the nanoparticles synthesis of IrO2 and RuO2 was performed to obtain two types of DSA electrodes named Class I and II to degrade oxamic acid. For Class I and II DSA, the nanoparticles used were synthesized separately and in the same reaction medium, respectively. Electrolysis were carried out in an open cylindrical cell without division at 25 °C, DSAs were used as anodes and a stainless-steel electrode as cathode, both elements have a geometric area of 2.8 cm2 immersed in 0.05 mol L−1 of NaCl or Na2SO4 and a current density of 3 mA cm−2 was applied for 6 h. Active chlorine species generated in the absence of oxamic acid in NaCl were also detected and quantified through ion chromatography. In Na2SO4 there was no degradation of the compound, but in NaCl the oxamic acid concentration reaching 85% with Class I DSA. The same tendency is observed in mineralization, in which Class I DSA allowed reaching a CO2 transformation close to 73%. The difference in the results occurs because with Class I DSA, more hypochlorite is generated than with Class II and therefore there is a larger amount of oxidizing species in the solution that enables the degradation and mineralization of oxamic acid.

Effect of saline organic acid solutions applied during soft wheat tempering on microbial load and flour functionality

AbstractBackground and objectivesIn recent years, special concern has been raised about the safety of wheat‐based products. In light of several incidents of foodborne illness associated with flour, the objectives of this study were designed to (a) evaluate the efficacy of saline organic acids solutions to reduce the natural microbiota of soft wheat grain and flour, and (b) to assess the impact of these tempering solutions on the functional properties of soft wheat flour.FindingsThe microbial load of the tempered wheat was significantly reduced by all saline organic acid treatments. The combination of 5.0% lactic acid–NaCl was the most effective against aerobic mesophilic bacteria and Enterobacteriaceae, with average reductions of 3.1 ± 0.1 and 4.5 ± 0.0 log CFU/g, respectively. In addition, this tempering solution yielded flour with a significantly lower microbial load compared with the control. Tempering with saline organic acid solutions did result in minor, but significant, variations in the solvent retention capacity profile of some flours. However, the treatments did not cause significant changes in the pasting profile of flours or in the physical characteristics and texture profile of baked cookies.ConclusionsThe addition of organic acids and NaCl to the tempering water improved the microbiological quality of the wheat grain and the resulting flour without compromising its functionality.Significance and noveltyThis study evaluates the inclusion of antimicrobial agents in the water used to temper wheat grain prior to milling as a practical method to reduce the number of microbial contaminants in flour and flour‐based foods that are at risk for consumption without cooking or any killing step.

Thermodynamic study on levulinic acid in NaCl, (C2H5)4NI and mixed MgCl2/NaCl and CaCl2/NaCl aqueous solutions at T = 298.15 K

Some thermodynamic properties of levulinc acid (LA) were studied under different experimental conditions. The partition coefficient between 2-methyl-1-propanol/pure water (or NaCl aqueous solutions up to I = 1.00 mol dm−3) was measured at T = 298.15 K by means of potentiometric titrations. The protonation constant of levulinic acid was also determined potentiometrically at different ionic strengths in NaCl(aq), (C2H5)4NI(aq) as well as in mixed MgCl2/NaCl and CaCl2/NaCl aqueous solutions.The protonation enthalpy was determined by calorimetric titrations in the same conditions of temperature and ionic strength.The linear fitting of the distribution ratio (log KD) determined at different salt concentrations vs. the salt concentration allowed for the determination of the distribution coefficient at infinite dilution (logKD00 = −0.14 ± 0.02), the Setschenow (km = 0.35 ± 0.03) and the activity coefficient of the neutral species (log γHL = km·msalt). The activity coefficient of the charged L− species was also computed by means of the Specific Interaction Theory (SIT) approach by keeping constant the value of the activity coefficient for the neutral HL species.The medium effect on the protonation constant was also studied using the weak interaction model, namely by comparing the protonation constants obtained in NaCl(aq), (C2H5)4NI(aq) as well as in mixed aqueous MgCl2/NaCl and CaCl2/NaCl mixtures by considering the formation of a NaL(aq), CaL+(aq), and MgL+(aq) species.

IN VITRO EVALUATION OF ANTIMICROBIAL ACTIVITY AND PROBIOTIC POTENTIAL OF LACTOBACILLUS STRAINS AGAINST SOME HUMAN PATHOGENS

Objective: Curd and yogurt are the major source of probiotic consumed by majority of the Indian population and Lactobacillus spp. are the predominant bacterial species in them. The present study was carried out to isolate Lactobacillus spp, from locally available dairy products and assess for the probiotic potential. Methods: The isolated were identified using biochemical assays and assessed for the properties such as Acid tolerance, Bile tolerance and NaCl tolerance. The identified strains were also subjected to antibiotic susceptibility and Antimicrobial activity using standard methodology. Results: A total of ten Lactic acid bacteria were isolated form different sources, belonging to different Lactobacillus species viz. L. acidophilus IAMb-3, L. brevis IAMb-6, L. bulgaricus IAMb-9, L. lactis IAMb-10, L. acidophilus IAMb-11, L. fermentum IAMb-13, L. casei IAMb-14, L. casei IAMb-15, L. plantarum IAMb-16 and L. rhamonsus IAMb-18. These identified strains were able to tolerate pH-3, 0.3% bile salt and upto 5-6% NaCl. Seven out of ten stains had antimicrobial activity against the pathogenic strain used in the study. Conclusion: In the present study the some of the potential probiotic strains have been isolated from local commercial and homemade sources. The isolated strains were capable of tolerating the harsh similar to human gut environment and found antagonistic to gut pathogens, hence can considered as potential probiotics.

Effect of rare earth oxide nano-additives on the corrosion behavior of Fe-based hardfacing alloys in acid, near-neutral and alkaline 3.5 wt.% NaCl solutions

In this paper, effect of rare earth oxide nano-additives on the corrosion behavior of Fe-based hardfacing alloys was studied. The corrosive solutions were 3.5wt.% NaCl+0.01mol/L HCl solution, 3.5wt.% NaCl solution and 3.5wt.% NaCl+0.01mol/L NaOH solution. The deep-etched microstructure of the hardfacing alloys was observed. The potentiodynamic polarization curves and electrochemical impedance spectra were used to study the corrosion behavior of the hardfacing alloys. The polarization test results showed that nano-additives shifted the corrosion potentials of the hardfacing alloys towards the noble direction in corrosive solutions. The values of the equivalent circuit elements for the impedance spectra of the hardfacing alloys indicated that nano-additives increased the corrosion resistance of the hardfacing alloys. When the content of nano-additives was 0.3wt.%, the hardfacing alloy possessed the maximum charge transfer resistance in acid NaCl solution. The hardfacing alloy with 0.6wt.% nano-additives had the maximum charge transfer resistance in near-neutral and alkaline NaCl solutions. The change in volume fraction of the primary and eutectic carbides and refinement of primary carbide influenced the corrosion behavior of the hardfacing alloys.

Examination of the usability of the MALDI-TOF method in sunflower genetic identity analyses

Economically, one of our most important crop is the sunflower. Regarding its production it is essential to use top quality seeds. As the conditions of seed certification and the certification parameters are regulated by laws and ordinances, it is highly important to farmers and seed producers to detect seeds of low quality or dubious origins.Nowadays, the examination of the cultivar homogenity of sunflower is based on a reference method of the International Seed Testing Association Rules International (ISTA), Chapter 8. This standard reference method uses ultrathin poliakrilamid isoelectric focusing gel electrophoresis (IEF-UTL, or simply IEF). With this work we have set out to compare the results of MALDI-TOF to the test results – used as reference results – achieved by this reference method. The aim is to develop a new, quick, cheap and reliable method. In this article I summarized the results of some of the experiments that will provide basis for my further work.During our previous experiments we have concluded that out of four extracting agents we can get the most protein markers using NaCl acid buffer, 1 propanol buffer.

Adsorption and corrosion inhibition properties of floxapen compound on the electrochemical characteristics of type-A5-series aluminium in sodium chloride solution

The inhibition performance of floxapen compounds on the electrochemical corrosion behaviour of A5 series aluminium in 3.5% NaCl acid solutions was studied through weight loss method and potentiodynamic polarisation test. The results obtained showed that the organic drug compound performed effectively in sodium chloride solutions with average floxapen compounds inhibition efficiency of 68% from weight loss and potentiodynamic polarisation test respectively. Results from corrosion thermodynamic calculations showed that the adsorption of floxapen compounds onto the aluminium was through chemisorption mechanism whereby the redox electrochemical progression responsible for corrosion initiation and the electrolytic transport of corrosive anions were concurrently suppressed. Adsorption of the compound was determined to obey the Langmuir and Frumkin isotherm model.

Abstract 5134: Pharmaceutical effect of vitamin C (ascorbate) on B16 melanoma in vitro and in vivo

Abstract In 2014, 76,100 new cases of melanoma were diagnosed in the United States. Treatment consists of surgery and chemotherapy, but efficacy is low. Indeed, five-year survival rates for patients with metastatic melanoma remain below 25%, indicating the need for new therapeutic strategies. In parallel, some studies indicate that vitamin C (ascorbic acid, ascorbate) only in pharmacologic doses may have a beneficial anti-tumor effect. Although ascorbate is an essential nutrient for humans, who are unable to synthesize it, pharmacologic ascorbate concentrations are achieved by parenteral administration. Although pharmacologic ascorbate in cancer treatment in humans is unproven, many studies report a selective cytotoxic effect in cancer cells in vitro. Cytotoxicity is thought to be mediated by hydrogen peroxide formation. To investigate the effect of high dose ascorbate in melanoma, we first used a murine melanoma cell line B16F10. We confirmed that ascorbate induced cell death in a dose-dependent manner (up to 40mM) in this cell line which is mostly reversed by adding catalase into the media, reinforcing the hydrogen peroxide dependent effect. We next investigated the role of ascorbic acid in vivo using a murine B16 melanoma model. Tumor-bearing C57BL/6 mice were treated with pharmacological ascorbic acid (4g/kg mice/twice a day) or hypertonic NaCl solution. We observed that the tumor size was decreased by 63% in the vitamin C treated group compared to the control group. We also used this model to analyze collagen expression in B16 tumors from ascorbate or saline-treated mice by qPCR and ELISA. Vitamin C treated tumors showed increased expression of various types of collagen. Indeed, we observed a five-fold increase in Col1A1, Col1A2, Col1A3, Col8A1 and Col28A1 mRNA expression and we also observed an increase in the Prolyl 4-hydroxylase, alpha peptide III (P4HA3) expression, an enzyme involved in collagen formation. No side effects were evident from administration of high dose ascorbate, which is fully consistent with previously published clinical data. We are currently investigating the role of hydrogen peroxide in the murine model by generating tumors with B16F10 cells that overexpress catalase. Taken together, these results showed that pharmacologic ascorbate is cytotoxic to B16F10 melanoma cells, with cytotoxicity in vitro mediated by hydrogen peroxide. Ascorbate is effective in reducing melanoma tumor size without apparent host toxicity. These data support the idea that vitamin C should be studied in humans both for combination chemotherapy and also as a stand-alone treatment. Citation Format: Pierre-Christian Violet, Nermi L. Parrow, Serrano L. Oscar, Jacqueline Yang, Mark A. Levine. Pharmaceutical effect of vitamin C (ascorbate) on B16 melanoma in vitro and in vivo. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 5134. doi:10.1158/1538-7445.AM2015-5134

Effect of Sealing Treatments on the Corrosion Behavior of Micro-arc Oxidation Coating on Aluminum Alloy in Acid NaCl Solution

Effect of Sealing Treatments on the Corrosion Behavior of Micro-arc Oxidation Coating on Aluminum Alloy in Acid NaCl Solution

Hydrogeochemical features of Lake Ngozi (SW Tanzania)

Located on the triple rift junction hosting the Karonga-Usungu depression in Tanzania, Lake Ngozi is the second largest crater lake of the East African Rift. The lake has a number of peculiar features: it has a near constant water level, no permanent surface inlets and outlets, it is vertically well-mixed, with homogeneous distribution of temperature and chemical composition, and it is characterised by near neutral to slightly acid Na–Cl waters of comparatively high salinity and high P–CO2. Based on the different chemical signature of surface and ground waters (low-Cl type) from lake waters, mass balance methods have been applied to investigate lake dynamics. Water enters the lake mainly by precipitation and groundwater inflow, and leaves by groundwater outflow and evaporation. A large groundwater outflow of 2.4myr−1 has been estimated. The high salinity, Na–Cl signature of Lake Ngozi waters, together with 3He/4He ratios measured on dissolved gases (between 7 and 8.3 Ra) and high-PCO2 values estimated all along the water vertical column indicate the inflow of deep-seated fluids, likely magmatic in origin, into the lake. The existence of a hydrothermal system possibly at 250°C in the root of the volcanic edifice is also hypothesised on the basis of solute geothermometry. Despite the current lack of vertical stratification, the lake is suspected to act as condenser for CO2 and other gases of deep magmatic origin, and should be then further monitored for the risk of limnic eruptions as well as for environmental and climatic concerns.

Osmotic Coefficients and Activity Coefficients in Aqueous Aminoethanoic Acid–NaCl Mixtures at 298.15 K

Osmotic coefficients are inferred from vapor pressure osmometry measurements that were performed at T = 298.15 K for ternary amino acid–electrolyte–water systems with variation in the concentrations of amino acid (aminoethanoic acid, glycine) and electrolyte (NaCl) up to high concentrations of aminoethanoic (3 mol·kg–1) and NaCl (3 mol·kg–1). From the consideration of the Gibbs–Duhem equation at mutual data treatment, interparticle interactions in ternary aminoethanoic acid–NaCl–water systems have been deduced in a wide concentration range. A two-parameter fit (third order terms in the power series) according to Bower and Robinson is used for calculation of component activity coefficients.

Biodegradable, multiple stimuli-responsive sodium deoxycholate–amino acids–NaCl mixed systems for dye delivery

Multiple stimuli-responsiveness of NaDC–amino acid–NaCl mixed systems.

Extractive metals from metallic powders recovered from waste printed circuit boards

Leaching behaviours of metallic powders were investigated using electrically generated chlorine at the anode chamber containing sulphuric acid solution, NaCl and CuSO4. Various parameters, which included the solid/liquid ratio, current density, concentration of NaCl, CuSO4, and H2SO4, leaching temperature, particle size, and stirring speed, were studied to understand the mechanism of leaching metallic powders. The capability of dissolved metallic powders increased with the increase in all parameters except the solid/liquid ratio. Leaching metallic powders were transport-controlled with a low activation energy of 14·7 kJ mol−1. The dissolved copper could be transferred from the anodic chamber to the middle chamber by solvent extraction technology. In the electric field, copper ions are transferred from the middle chamber to the cathodic chamber through a cation exchange membrane (CEM) and electrodeposited to form copper foils. The tensile strength and elongation percentage of 65 μm-thick copper foils were 276 Mpa and 10·66%, respectively. The utilisation of metallic powders recovered from waste PCBs (WPCBs) could produce high-performance copper foil.On a examiné le comportement de lixiviation de poudres métalliques en utilisant du chlore engendré par électricité dans la chambre de l’anode contenant une solution d’acide sulfurique, du NaCl et du CuSO4. On a étudié une variété de paramètres, incluant le rapport solide à liquide, la densité de courant, la concentration de NaCl, de CuSO4 et d’H2SO4, la température de lixiviation, la taille de particule et la vitesse d’agitation, afin de comprendre le mécanisme de lixiviation des poudres métalliques. La capacité des poudres métalliques dissoutes augmentait avec l’augmentation de tous les paramètres, sauf le rapport solide à liquide. Les poudres métalliques de lixiviation étaient contrôlées par le transport, avec une faible énergie d’activation de 14·7 kJ/mol. On pouvait transférer le cuivre dissous de la chambre anodique à la chambre du milieu au moyen de la technologie d’extraction par solvant. Dans un champ électrique, les ions de cuivre étaient transférés de la chambre du milieu à la chambre cathodique par une membrane d’échange de cation et étaient déposés par galvanoplastie pour former des feuilles de cuivre. La résistance à la traction et le pourcent d’élongation de feuilles de cuivre de 65 μm d’épaisseur étaient respectivement de 276 MPa et de 10·66%. Les poudres métalliques récupérées de cartes de circuit imprimé de rebut pourraient produire une feuille de cuivre à haute performance.

Laboratory Study on the Hygroscopic Behavior of External and Internal C2–C4Dicarboxylic Acid–NaCl Mixtures

Atmospheric aerosol is usually found to be a mixture of various inorganic and organic components in field measurements, whereas the effect of this mixing state on the hygroscopicity of aerosol particles has remained unknown. In this study, the hygroscopic behavior of mixtures of C2-C4 dicarboxylic acids and NaCl was investigated. For both externally and internally mixed malonic acid-NaCl and succinic acid-NaCl particles, correlation between water content and chemical composition was observed and the water content of these mixtures at relative humidity (RH) above 80% can be well predicted by the Zdanovskii-Stokes-Robinson (ZSR) method. In contrast, a nonlinear relation between the total water content of the mixtures and the water content of each chemical composition separately was found for oxalic acid-NaCl mixtures. Compared to the values predicted by the ZSR method, the dissolution of oxalic acid in external mixtures resulted in an increase in the total water content, whereas the formation of less hygroscopic disodium oxalate in internal mixtures led to a significant decrease in the total water content. Furthermore, we found that the hygroscopicity of the sodium dicarboxylate plays a critical role in determining the aqueous chemistry of dicarboxylic acid-NaCl mixtures during the humidifying and dehumidifying process. It was also found that the hydration of oxalic acid and the deliquescence of NaCl did not change in external oxalic acid-NaCl mixtures. The deliquescence relative humidity (DRHs) for both malonic acid and NaCl decreased in both external and internal mixtures. These results could help in understanding the conversion processes of dicarboxylic acids to dicarboxylate salts, as well as the substitution of Cl by oxalate in the atmosphere. It was demonstrated that the effect of coexisting components on the hygroscopic behavior of mixed aerosols should not be neglected.

The Extraction Behavior of Cu&lt;sup&gt;2+&lt;/sup&gt; with N,N,N',N'-Tetrabutyl-3-Oxy-Glutaramide from Hydrochloric Acid

The extraction behavior of Cu2+ using N,N,N,N-tetrabutyl-3-oxy-glutaramide from hydrochloric acid was studied. The effect of hydrochloric acid concentration, NaCl concentration, extractant concentration, and temperature on the extraction distribution of Cu2+ was also investigated. The result shows that the distribution ratio increases with an increase of the acid concentration, NaCl concentration or extractant concentration, but decreases with temperature, which demonstrates that the extraction reaction is exothermic.

Effect of nitriding on corrosion behaviour of graphite reinforced aluminium alloy composites

The paper evaluates the effect of nitriding treatment on the corrosion behaviour of graphite reinforced aluminium alloy 6061 composites. The composites were prepared using the liquid metallurgy technique. The graphite content in the composites was varied from 1 to 7% (by weight) in steps of 2%. The nitriding process was carried out at 500°C for 24 h. Energy dispersive X-ray analysis was used to confirm the implantation of nitrogen in the composites. Three categories of specimens, namely, the nitrided composites, non-nitrided composites as well as non-nitrided and unreinforced specimens, were tested. Immersion corrosion test using the weight loss method was employed to study the effect of corrosion over a period ranging from 24 to 120 h in steps of 24 h at ambient temperature. The test solution used was aerated 1 N NaCl acid. It was observed that the nitrided specimens exhibited less weight loss compared to the non-nitrided specimens in general. The composites with greater content of graphite exhibited low corrosion rate.

Preparation and deproteinization of garlic polysaccharide

Preparation and deproteinization methods of polysaccharide from garlic (Allium sativum L.) were studied. The crude polysaccharide was prepared by the method of hot water extraction. The percentages of deproteinization and polysaccharide loss were compared as indexes using the hydrochloric acid (HCl) method, trichloroacetic acid method, NaCl method and CaCl2 method, respectively. The infrared spectra analysis and content analysis showed that the HCl method exhibited the highest percentage of deproteinization, and a little higher percentage of polysaccharide loss than the other three methods. The CaCl2 method exceeded NaCl method in deproteinization.