Chlorine Ion Concentration Research Articles

Experimental Study of Influence Factors on Carbon Dioxide Corrosion

CO2 corrosion is more prominent in the petrochemical industry, for different influencing factors of CO2 corrosion, 1Cr18Ni9Ti, 316L, TA2, Q235, 45 steel materials are selected for the study. Using immersion experiment and electrochemical experiment to study the corrosion behavior of these experimental materials in CO2 environment under different external conditions. We finally obtain the law of influence of the temperature, pH, concentration of chlorine ion and alloy elements on the CO2 corrosion.

Study on the wastewater disinfection at the boron-doped diamond film electrode

Abstract Under the various current densities, flow rates and the chlorine ion concentrations, the water disinfection in secondary sedimentation tank at boron-doped diamond film electrode was studied. The results showed that the disinfection rate increases with the larger current density and smaller flow rate; it is worthy of note that the chlorine ion concentration has remarkable effects on the wastewater disinfection. After the same cycle numbers, the larger chlorine ion concentration would induce more oxidants in the solution, and then certainly lead to the better disinfection effect. To obtain the higher disinfection rate under a certain chlorine ion concentration, long contact time between the wastewater and the electrode is necessary.

Effectiveness of self-adhesive luting cements in bonding to chlorhexidine-treated dentin

ObjectivesThe aim was to investigate the microtensile bond strength (μ-TBS) and failure pattern of self-adhesive luting cements (SLC) to dentin pre-treated with different concentrations of chlorhexidine (CHX) solutions. MethodsThe occlusal enamel was removed from 30 extracted sound human molars in order to expose a flat dentin. Resin-composite (Filtek Z250, 3M ESPE) discs (12mm in diameter, 6.0mm thickness) were cemented to the smear layer-covered dentin using the SLC [RelyX U100, 3M ESPE (U100); Multilink Sprint, Ivoclar Vivadent (MS)] with 0.2% or 2.0% CHX solutions. Results were compared with the control, untreated dentin. Six groups were then created based on the SLC and dentin pre-treatment (n=5). After 24h of water storage, restored teeth were serially sectioned into beams with a cross-sectional area of 0.8mm2 at the bonded interface. Subsequently, specimens were tested in tension with a crosshead speed of 0.5mm/min in a universal testing machine, and the failure patterns were classified. Two-way ANOVA and Tukey's tests were performed (α=0.05). Additionally, 18 teeth were subjected to energy-dispersive X-ray spectroscopy (EDS) analysis and micromorphology characterization of the smear layer-covered dentin and 0.2% or 2.0% CHX-treated dentin surfaces. ResultsThe μ-TBS obtained for both control groups were significantly higher, regardless of the CHX concentration and/or the cement used. Bond strengths were significantly higher for U100 than for MS, except when 2.0% CHX was applied. Fractographic analysis indicated that most failures in the control groups occurred cohesively in the SLC. Pre-treated dentin with 0.2% and 2.0% CHX solutions presented higher incidences of adhesive failures. EDS/SEM analysis exhibited varied concentrations of chlorine ions and crystal-shaped precipitates, depending upon the CHX concentration. SignificancePre-treatment of dentin with 0.2% or 2.0% CHX adversely affects the bonding efficacy when associated with the SLCs tested.

Wheat response to combined application of nitrogen and phosphorus in a saline sandy loam soil

Fertilization with nitrogen (N) or phosphorus (P) can improve plant growth in saline soils. This study was undertaken to determine wheat (Triticum aestivum L; cv Krichauff) response to the combined application of N and P fertilizers in the sandy loam under saline conditions. Salinity was induced using sodium (Na+) and calcium (Ca2+) salts to achieve four levels of electrical conductivity in the extract of the saturated soil paste (ECe), 2.2, 6.7, 9.2 and 11.8 dS m−1, while maintaining a low sodium adsorption ratio (SAR; ≤1). Nitrogen was applied as Ca(NO3)2 · 4H2O at 50 (N50), 100 (N100) and 200 (N200) mg N kg−1 soil. Phosphorus was applied at 0 (P0), 30 (P30) and 60 (P60) mg kg−1 soil in the form of KH2PO4. Results showed that increasing soil salinity had no effect on shoot N or P concentrations, but increased shoot Na+ and chlorine ion (Cl−) concentrations and reduced dry weights of shoot and root in all treatments of N and P. At each salinity and P level, increasing application of N reduced dry weight of shoot. At each salinity and N level P fertilization increased dry weights of shoot and root and shoot P concentration. Addition of greater than N50 contributed to the soil salinity limiting plant growth, but increasing P addition up to 60 mg P kg−1 soil reduced Cl− absorption and enhanced the plant salt tolerance and thus plant growth. The positive effect of the combined addition of N and P on wheat growth in the saline sandy loam is noticeable, but only to a certain level of soil salinity beyond which salinity effect is dominant.

Erosion-Resisting Properties for Chloride Ion of Short-Chopped Basalt Fiber Reinforced Concrete

According to a test for chloride ion erosion in concrete under designed manual climate environment, distributions of chlorine ion concentration in pure bending concrete of short-chopped basalt fiber RC beam and check RC beam without fiber with different flexural loads are analyzed in this paper, and diffusion coefficients of compression and tensile concrete are fitted on the basis of Fick’s second law. Analysis results show that erosion-resisting properties for chloride ion of the basalt fiber compression and tensile concrete in the pure flexural region are increased

Technical Description of Parameters Influencing the pH Value of Suspension Absorbent Used in Flue Gas Desulfurization Systems

As a result of the large limestone deposits available in Poland, the low cost of reagent acquisition for the large-scale technological use and relatively well-documented processes of flue gas desulfurization (FGD) technologies based on limestone sorbent slurry, wet scrubbing desulfurization is a method of choice in Poland for flue gas treatment in energy production facilities, including power plants and industrial systems. The efficiency of FGD using the above method depends on several technological and kinetic parameters, particularly on the pH value of the sorbent (i.e., ground limestone suspended in water). Consequently, many studies in Poland and abroad address the impact of various parameters on the pH value of the sorbent suspension, such as the average diameter of sorbent particles (related to the limestone pulverization degree), sorbent quality (in terms of pure calcium carbonate [CaCO3] content of the sorbent material), stoichiometric surfeit of CaCO3 in relation to sulfur dioxide (SO2) absorbed from flue gas circulating in the absorption node, time of absorption slurry retention in the absorber tank, chlorine ion concentration in sorbent slurry, and concentration of dissolved metal salts (Na, K, Mg, Fe, Al, and others). This study discusses the results of laboratory-scale tests conducted to establish the effect of the above parameters on the pH value of limestone slurry circulating in the SO2 absorption node. On the basis of the test results, a correlation equation was postulated to help maintain the desirable pH value at the design phase of the wet FGD process. The postulated equation displays good coincidence between calculated pH values and those obtained using laboratory measurements.

Study of Fe3Al Corrosion Behavior in Simulating Marine Biofilm Environment

Calcium Alginate is a kind of natural biopolymer which can be deposited on metal surfaces to form film. In this work, microbe film was simulated by Calcium Alginate gel, according to the natural structure and property of microbe film. Acetic acid, manganese dioxide, and sodium sulfide were added separately in sodium chloride solution to simulate different bacteria culture systems. The corrosion behavior of Fe3Al was investigated in simulating biofilm environment by open circle potential, polarization curves, and electrochemical impedance. Electrochemical results show that the passivating film formed immediately when Fe3Al electrodes exposed in simulated seawater. The corrosion process of Fe3Al in the medium with manganic sediment was mainly dominated by oxygen diffusion. In the simulated environment with acetic acid, the pitting corrosion potential on the surface of Fe3Al moved towards negative accompanied with the increasing concentration of chlorine ion and the decreasing value of pH. Simulated sulphate reduce bacteria (SRB) accelerated cathodic polarization process of Fe3Al surface, corrosion potential dropped sharply and the surface oxidative membrane broken when polarization potential reached −0.5 V, indicating that Fe3Al can be easier corroded by SRB than by other bacteria.

Long-term variations of water quality of the Selenga and Kiran rivers at the Russian-Mongolian boundary

Principal-Component Method is used to identify the major factors governing the long-term variations of water chemistry in the transboundary rivers of Selenga and Kiran. Their preliminary interpretation was made. Water chemistry formation in both large (Selenga) and small (Kiran) rivers is shown to be mostly governed by natural-climatic factors. Thus, an increase in water abundance has a dual effect on water chemistry: on the one hand, water is enriched with substances increasingly entering it because of the more intense erosion and dissolution of solid rocks, and, on the other hand, the concentrations of chemicals of anthropogenic origin decrease because of their greater dilution. A conclusion was made regarding a relationship between a positive trend in water temperature and an increase in the concentration of chlorine ion in water. A preliminary estimate is given to the effect of municipal and industrial wastes, as well as surface and subsurface waters of various genesis on long-term variations of river water chemistry. Trends in changes in water chemistry were studied by using approximations of long-term series of the variables that determine the interpretation of principal factors with the help of a slow trend by “caterpillar” method.

동(Cu) 및 동합금(Bronze)의 부식생성물과 탈염처리

【Benzotriazole (B.T.A) which has been mainly used for the stabilization processing method of excavated copper and bronze artifacts is vaporized within 2~3 years after the usage because it is unstable at the acid conditions and cannot protect the surface of artifacts. In this study, NaOH method which has been used for the steel artifacts was applied as a stabilization process for the method of copper and bronze artifacts to gush chlorine ion out. For the reproduction of excavated samples, copper and bronze plates were dipped in 0.1M HCl for 26 hrs to form CuCl, rusted at $70^{\circ}C$ with RH 75% for the formation of corrosion products, and desalted in 0.1 M NaOH solution. The concentration of chlorine ion was measured by using ionchromatography. During the desalting process, a large quantity of chlorine ions was gushed out in early period and corrosion products were not additionally generated through the re-corrosion experiment. This NaOH desalting process was found to be a method of stabilization process for copper and bronze artifacts from the formation of Tenorite (CuO) during desalting as a protection layer for corrosion.】

A model of active transport of ions in hepatocytes

A mathematical model of the transport of basic ions (K+, Na+, Cl-) across the hepatocyte membrane has been created using the previously constructed models of active ion transport in biomembranes. The dependence of the resting potential on extracellular ion concentration has been established. Using the model, it is possible to independently calculate the resting potential at the biomembrane and the concentrations of sodium, potassium, and chlorine ions in the cell. The calculated internal concentrations of the ions are in good agreement with the corresponding experimental values.

Electrochemical anodic dissolution of FeCuNiCoMn alloy in ammonium solutions containing clorine ions

The effect of chlorine ion concentration, temperature and current density on metal distribution among the electrolyte, cathode deposit and mud in the process of electrochemical dissolution of FeCuNiCoMn alloy in an ammonium medium is examined. High iron content (65.90%) compared to that of non-ferrous metals (12.07% Cu, 12.81% Ni, 1.30% Co) and Mn 5.33% is a specific feature of the alloy. The alloy was produced by means of high-temperature reduction smelting of manganese nodules from the Clarion Cliperrton area in the Pacific Ocean. It was found that electrochemical dissolution of the alloy is accompanied by formation of a CuNiCo-cathodic deposit and two types of mud: one tightly clinging to the anode surface, and another, finely suspended in the electrolyte. The highest-purity cathode deposit in mass %: 40.28 Cu, 50.27 Ni, 1.21 Co, 7.63 Fe and 0.61 Mn was obtained at ion ratio in the solution NH4+: Cl− = 2.5: 0.5, temperature 323 K, anodic current density 350 A/m2, separation of the anode and cathode spaces by a shielding screen, continuous removal of the anodic mud and maintaining of a constant pH in the electrolyte (10 ± 0.2). In these conditions, >99% of Fe and Mn, 25% Cu, 54% Ni and 52% of Co is transferred into the mud.

Study of the Reaction Rate of Gold Nanotube Synthesis from Sacrificial Silver Nanorods through the Galvanic Replacement Method

An investigation was carried out about the gold nanotube synthesis via a galvanic replacement reaction. The progress of the gold nanotube synthesis was investigated using electron microscopy and UV‐Vis spectroscopy. In addition, the reaction rates of gold nanotube formation in the early stage of the reaction were studied. The chlorine ion concentration linearly increased with the gold precursor concentration but deviated from the stoichiometric amounts. This deviation was probably due to AgCl precipitates formed by the reaction of chlorine ions with dissolved silver ions. The replacement reaction was promoted with increased temperature and was nonlinearly proportional to the gold ion concentration. The outcomes of this research will enhance the current understanding of the galvanic replacement reaction.

Effects of Chlorine Ion on the Photocatalytic Activity of Cuprous Oxide Powders Prepared by Hydrothermal Method

Cuprous oxide(Cu2O) microcrystals were successfully synthesized via hydrothermal method using CuSO4•5H2O and Na2SO3 in HAc-NaAc buffer solution. The products were characterized by X-rays diffraction (XRD) ,scan election microscopy (SEM) and ultraviolet-visible (UV-vis) spectroscopy. The photocatalytic activity of the as-prepared Cu2O powders was evaluated by the photocatalytic degradation of methyl orange solution under visible light irradiation at room temperature in air. The effects of chlorine ion on the photocatalytic activity of the Cu2O powders were investigated and discussed. The results show that chlorine ion in solution can obviously decrease the photocatalytic activity of Cu2O. When the concentration of chlorine ion increased to 0.5mol/L(about Cl- concentration in the seawater), the photocatalytic ratio of Cu2O decrease to 45% compared with the value in pure water. Increasing solution pH can enhance the photocatalytic activity of Cu2O. The mechanism of photo-degradation was discussed.

Compactação primária do abomaso em 14 bovinos no estado de Pernambuco

Apesar de forragens grosseiras e secas serem empregadas comumente na alimentação de vacas em várias regiões, especialmente durante o período seco, a compactação primária do abomaso tem sido pouco relatada no Brasil, provavelmente pela dificuldade de diagnóstico dos veterinários de campo. Este trabalho objetivou realizar um estudo retrospectivo sobre a compactação primária do abomaso em 14 bovinos no Estado de Pernambuco. Oito casos considerados moderados, sem grave distensão abdominal e sem compactação do rúmen, foram tratados conservativamente e quatro casos graves, com severa distensão abdominal e compactação do rúmen, foram tratados cirurgicamente. Um touro foi encaminhado para abate e uma vaca morreu antes de receber qualquer tratamento. O maior número de casos de compactação do abomaso ocorreu em bovinos da raça Holandesa com seis casos (42,9%), seguido por animais mestiços com cinco casos (35,8%) e as raças Pardo-Suiça, Nelore e Marchigiana com um caso cada (21,3%). A composição da alimentação oferecida caracterizou-se por conter fibra de baixa qualidade e variou bastante dentre os casos. Os sinais clínicos mais frequentes foram comportamento apático, desidratação, timpanismo ruminal associado à hipomotilidade, distensão abdominal, hipomotilidade intestinal e fezes escassas ou ausentes com presença de muco. Os achados hematológicos revelaram, na maioria dos casos, leucocitose por neutrofilia e hiperfibrinogenemia. Na análise do fluido ruminal havia comprometimento da dinâmica da flora e fauna microbiana, e elevação no teor de cloreto. O índice de recuperação clínica (4/8) e cirúrgica (2/4) observado neste estudo foi de 50%. As condutas clínica e cirúrgica permanecem como opções viáveis para o tratamento das compactações leves e severas, entretanto o prognóstico é considerado reservado, principalmente quando associado à gestação avançada.

The effect of the microrelief on salinization of semidesert soils

The microrelief affects the distribution of soluble salts in the upper horizons of salt-affected soils. This has been shown for semidesert soils—meadow solonchak, solonchakous meadow, and meadow soils—within the Sulak Lowland in the Republic of Dagestan. The total content of salts and the concentrations of sodium, magnesium, chlorine, and sulfate ions are higher in the soils of microelevations. However, no significant effect of the microrelief on the distribution of calcium in the soil water extracts has been found. The properties of the solid soil phase (the humus content and the content of adsorbed bases, including calcium, magnesium, and sodium) and the soil pH are not reliably differentiated by the elements of the local microtopography.

Hydrothermally prepared nanocrystalline Mn–Zn ferrites: Synthesis and characterization

Nanocrystalline particles of Mn x Zn 1− x Fe 2O 4 were prepared by chemical precipitation of hydroxides, followed by hydrothermal processing and freeze–drying. The synthesis involves the hydrolysis of aqueous metal precursors by using ammonia as precipitating agent. The chlorine ion concentration in the solution and the pH of the precipitation, are shown to play a crucial role in retaining the initial stoichiometry of the solution to the nanoparticles. The obtained products exhibited some interesting and unique features: they consisted of nanoparticles with sizes ranging from 5 to 25 nm, they had surface areas between 60 and 110 m 2 g −1 and pore sizes in the mesopore region (i.e. 8–20 nm). The produced materials were examined by powder X-ray diffraction for crystalline phase identification, scanning electron microscopy for grain morphology, high resolution transmission electron microscopy for particle size distribution and nitrogen sorption for surface area, pore volume and pore size distribution determination. The sintering of the ferrite powders was also studied by thermogravimetric analysis and dilatometry of the powders mixed with an organic binder to improve their compaction properties.

Effects of subchronic exposure to 2,6‐dinitrotoluene in the northern bobwhite (Colinus Virginianus)

Explosives and their breakdown products are commonly found in soils at U.S. military installations. Many areas where these compounds are found represent useful habitat for ground-foraging birds. Because these birds likely are exposed to such compounds, we evaluated the oral toxicity of 2,6-dinitrotoluene (DNT) in a representative ground-foraging species of management concern. Adult male and female northern bobwhite (Colinus virginianus) were exposed to either 0, 5, 10, 40, or 60 mg/kg/d via gavage for 60 d (subchronic) following determination of the median acute lethal dose (320 mg/kg). Circulating levels of red blood cells and hemoglobin were significantly decreased in a dose-dependent manner; however, levels remained within normal ranges. Plasma concentrations of total protein, albumin, globulin, aspartate aminotransferase, and potassium, sodium, and chlorine ions were significantly decreased, and circulating levels of uric acid were significantly increased. Decreased body weight, enlarged gallbladders, edematous gastrointestinal tracts, pale kidneys, pale and fibrous livers, and loose stools were consistent observations. The effects found in the clinical chemistries taken together with histopathological abnormalities observed in sections of hepatic and renal tissue suggest that the liver and kidneys are major targets for 2,6-DNT. Oral exposures to 2,6-DNT appear to affect northern bobwhite in a manner similar to that of the other main DNT isomer, 2,4-DNT, but in more subtle ways, adversely affecting the gastrointestinal system and leading to diarrhea and, ultimately, emaciation. The lowest-observed-adverse-effect level is 40 mg/ kg/d based on hematological measures, and the no-observed-adverse-effect level is 10 mg/kg/d based on the absence of results indicative of adverse effects.

耐塩性鉄酸化細菌の馴養による電気メッキ排水処理の検討

The iron-oxidizing bacterium, Thiobacillus ferrooxidans, is not halotolerant and cannot oxidize ferrous ions (Fe2+) to ferric ions (Fe3+) in electroplating wastewater containing high concentrations of chlorine ions. T. ferrooxidans cannot be used for the treatment of such electroplating wastewater. The acclimation of iron-oxidizing halotolerant bacteria has been studied to treat electroplating wastewater containing ferrous ions and a high concentration of chlorine ions. Iron-oxidizing bacteria that are halotolerant and able to oxidize Fe2+ to Fe3+ were obtained from the activated sludge of a steel works coke-oven wastewater treatment plant. A long-term experiment using artificial wastewater containing 20,000 mg · l-1 chlorine ions showed the stable performance of the Fe2+ oxidation ability by iron-oxidizing bacteria acclimated to seawater. It seems that the acclimated iron-oxidizing bacteria can be used for the treatment of electroplating wastewater. An analysis of genomic DNA extracted from the acclimated sludge of the reactor showed the existence of an analog of the iron-oxidizing bacterium, Thiobacillus prosperus.

Method of effective evaluation for examination of chloride ion in concrete

The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure's safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data obtained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep)and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods' precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.

Method of effective evaluation for examination of chloride ion in concrete

The chloride ion contained in reinforced concrete seriously corrodes the steel surface and damages concrete, resulting in inferior reinforced concrete that strength seriously compromises the entire structure's safety. Consequently, the examination of chloride ions contained in reinforced concrete becomes an important part of a complete quality control procedure. To effectively check the concentration of chloride ions in concrete, the evaluation process should be accurate and precise. Laboratory data obtained using existing evaluation methods for the examination of chloride ion are not sufficiently objective to yield reliable results with accuracy and consistency for each sample. An evaluation algorithm with capability to define indices of precision degree (Ep) and accuracy degree (Ea) is presented in this paper. The authors established a statistically reliable index of unbiased estimators and equations to critically examine the laboratory methods' precision, accuracy degrees and application value for measuring chlorine ion concentration in reinforced concrete.