Presence Of Chlorine Ions Research Articles

The degradation of 1,4 acetaminophen by electrocatalytic oxidation process and investigation the by-products of the system

The study was aimed at using Ti/IrO2-RuO2 electrocatalytic electrodes for the purpose of removing 1,4-acetaminophen from a solution. The electrooxidation process's efficiency was studied by controlling various parameters such as pH (3−11), current density (100–1000 A.m-2), electrolyte type (NaCl, Na2SO4, KCl), and conductivity (1.5–10 mS.cm-1). Additionally, H2O2 addition (100–1000 µL), and acetaminophen concentration (25–100 ppm) were also studied. In addition, it was found that when the initial concentrations were increased from 25 ppm to 100 ppm, there was a corresponding increase in the removal efficiencies, which ranged from 27% to 36% at a current density of 350 A.m-2 and a conductivity of 3.5 mS.cm-1 for a period of 90 min. The removal efficiency increased from 30% to 42% when 0.5 mL of 30% H2O2 was added to the initial concentration of 50 ppm. The presence of chlorine ions in a solution has been demonstrated to result in the formation of oxidation products. This result has enabled researchers to investigate the toxic and disinfecting properties of the solution. The LC-MS spectra analysis revealed the formation of intermediate degradation products. The identification of these metabolites enabled the suggestion of their structure and degradation mechanism.

Transient absorption study on Red Vermilion darkening in presence of chlorine ions and after UV exposure

The application of no destructive techniques in the field of Cultural Heritage is becoming fundamental to understanding degradation phenomena. In this study, Transient Absorption (TA) spectroscopy was exploited to explain the process which causes the darkening of Red Vermilion, a famous pigment known also as cinnabar. The optical properties involved in the process are studied in pure HgS and chlorine doped HgS samples, before and after exposure to UV light (365 nm). The study was carried out with particular attention on the ground state bleaching signals, directly connected to the formation of intra-gap trap levels responsible for the pigment degradation. First derivative reflectance spectra reveal the presence of these defectivities, while the analysis of Tauc plots from Kubelka Munk function confirms the reduction of energy band gap due to UV exposure. With the help of Density Functional calculations, we simulated the role of S vacancies in producing a defective alpha-phase, the consequent reduction of the energy band gap and, finally, the progressive phase transformation to the cubic metacinnabar. Transient Absorption turns out to be an important tool of diagnosis about the conservation state of pigments applied in the field of Cultural Heritage.

EFFICIENCY OF WATER-BASED ELECTROLYSIS DEPENDING ON TECHNOLOGICAL PARAMETERS OF CORROSIVE AND ANODE DISSOLUTION OF ALUMINUM

The paper presents the features of the synthesis of hydrogen released as a result of dissolution of the aluminum alloy AMg. To more fully determine the technological characteristics of hydrogen synthesis, we studied the volumes of hydrogen released in the reactor as a result of dissolution of the aluminum alloy AMg. The mechanism of alloy dissolution is established taking into account the effect of impurities in the alloy on the anodic dissolution process. The conditions for accelerating the anodic dissolution of the AMg alloy in the presence of chlorine ions under the conditions of the “negative differential effect” are determined. The dissolution of the AMg alloy in an alkaline chloride solution has an electrochemical nature, which is based on the electrochemical mechanism of hydrogen reduction with the subsequent process of its diffusion into the gas phase. Chloride ions accelerate the active dissolution of aluminum at current densities of 5 A/dm2 instead of 3 A/dm2 at room temperature and surface roughness of class 3-5 (≈5 μm). The greatest influence on the dissolution rate of the alloy has the concentration of NaOH, the dissolution temperature and the surface cleanliness class. The main technological indicator of the improvement of hydrogen electrosynthesis is the use of anodic depolarization of aluminum, its negative values and, as a consequence, the evolution of hydrogen on both electrodes. The depolarization effect is achieved by dissolving the aluminum alloy instead of the oxygen evolution reaction at the anode. The voltage on the cell is 2 times lower compared to industrial alkaline water electrolysis. This makes it possible to save up to 50% of electricity. The absence of oxygen evolution makes this process safer.

Methodology for testing pipeline steels for resistance to grooving corrosion

The methodology for testing pipeline steels is suggested on the assumption that for the destruction of pipes in field oil pipelines by the mechanism of grooving corrosion the simultaneous fulfillment of such conditions as the occurrence of scratches on the lower generatrix of the pipe, eventually growing into a channel in the form of a groove, emulsion enrichment with oxygen, presence of pipe wall metal in a stressed state, presence of chlorine-ion in the oil-water emulsion is required. Tests are suggested to be carried out in 3 % aqueous solution of NaCl with continuous aeration by air on bent plates 150×15×3 mm, made of the analyzed steel, the middle part of which is under the action of residual stresses σres, close to the level of maximum equivalent stresses σeqv in the wall of the oil pipeline, with the presence of a cut on this part on the inner side of the plate as an initiator of additional mechanical stresses. Using the value of the modulus of normal elasticity of the analyzed steel, the degree of residual strain of the elastic-plastic body from this material, corresponding to the value σres ≈ σeqv is calculated, based on which the plates are bent to the required deflection angle, after which the cut is applied to them. After keeping the plates in the corrosive medium for each of them the increase in depth of the cut as a result of corrosion of the walls by the corrosive medium is analyzed, from which the rate of steel K by the mechanism of grooving corrosion is calculated taking into account the duration of tests. Corrosion rate values for two pipe steel grades determined by the suggested procedure are given. The comparison of K values obtained leads to the conclusion about the higher resistance to grooving corrosion of 09G2S steel.

A Study of Cordierite Ceramics Synthesis From domestic kaolin

This work aims to study the effect of chlorine ion on the formation of the cordierite phase (2MgO.2Al2O3.5SiO2) from domestic kaolin at various calcined temperatures.. The cordierite phase was synthesized by a solid-state reaction technique from the mixture of kaolin, aluminum nitrate nonahydrate (Al(NO3)3.9H2O), and magnesium chloride hexahydrate (MgCl2.6H2O) which was designed to the stoichiometric composition of cordierite in the absence and presence of chlorine ion (NH4Cl). The structure and formation of cordierite phase were characterized by X-ray diffraction (XRD) and thermogravimetric - differential thermal analysis (TG-DSC). Phase composition of samples calcined at various temperatures was calculated by using Match! (Version 3.7.0) software. It is noteworthy that the presence of chlorine ion in the mixture declined the formation temperature of cordierite by 50 °C. The cordierite phase was calculated to be 61.3 wt.% and 5.5 wt.% at 1150 °C for the present and absent chlorine ion, respectively. The presence of chlorine ion affected the cordierite formation rate and suppressed the temperature of formation. Cordierite phase could be obtained up to 89.6 wt.% at 1250 °C and 30 wt.% NH4Cl. This investigation found that cordierite ceramic could be synthesized from domestic kaolin at lower temperature by using NH4Cl additive.

Preparation of Co/Ti electrode by electro-deposition for aqueous nitrate reduction

Abstract A Co/Ti electrode for nitrate reduction was prepared by electrode-deposition. In the single-compartment electrolysis cell, nitrate (100 mg/L) removal reached nearly 100% after 3 h electrolysis under the current density of 20 mA cm–2 by using the Co/Ti electrode as cathode, and the main reduction products were ammonium nitrogen (66.5%) and nitrogen gas (33.5%). This performance on nitrate removal was comparable to a Co3O4/Ti electrode, and the electroactivity of the Co/Ti electrode towards nitrite reduction was higher than that of a Co3O4/Ti electrode. The Co/Ti electrode exhibited an improved stability with 18.7% of mass loss and 25.5% of Co dissolution compared with the Co3O4/Ti electrode after ultrasonic interference. The presence of chlorine ion (1,000 mg/L) could promote the total nitrogen (TN) removal to approximately 100% after 3 h electrolysis because of the ammonium oxidation by the free chlorine produced from the anode. In the presence of calcium (50 mg/L) and phosphate (0.5 mg/L), the nitrate removal decreased from 85.4 ± 1.5 to 57.7 ± 3.5% after ten reuse cycles. This result suggests that Ca and P should be pre-removed before the electro-reduction of nitrate.

Synthesis and characterization of enhanced silica nanoparticle (SiO2) prepared from rice husk ash immobilized of 3-(chloropropyl) triethoxysilanea

Rice Husk Ash (RHA) is the by-product for rice mill industry and it is considered as waste material. It is considered a way to recycle materials, which is one of the types of renewable energy. Many types of research focused on RHA are targeting the high contain Sodium silicate. Sodium silicate to be converted to silica. The sol–gel technique offered a simple route in producing silica Rice husk ash immobilized with 3-(chloropropyl) trimethoxysilane (RHACCl) from RHA, where 3-(chloropropyl) trimethoxysilane (CPTES) is used to reduce the RHA into high-quality silica nanoparticle. Silica produced from this technique is found to have the presence of carbon; silicon and chlorine were determined by a combination of elemental analysis by EDX. UV–visible absorbance spectra of the RHACCl NPs silica samples having a wavelength of 333 nm showing absorbance in the ultraviolet region. FTIR spectroscopy scanning electron microscopy (FESEM) and energy dispersive spectrometry. The spectral proof obtained in this research showed that CPTES was installed on the SiO 2 surface. The reaction was successful through the presence of chlorine ion, which is considered an important organic function, and the presence of chlorine in the amorphous SiO 2 is an important starting point to developing the wide range from silica-based materials.

EFFICIENCY OF WATER-BASED ELECTROLYSIS DEPENDING ON TECHNOLOGICAL PARAMETERS OF CORROSIVE AND ANODE DISSOLUTION OF ALUMINUM

The paper presents the features of the synthesis of hydrogen released as a result of dissolution of the aluminum alloy AMg. To more fully determine the technological characteristics of hydrogen synthesis, we studied the volumes of hydrogen released in the reactor as a result of dissolution of the aluminum alloy AMg. The mechanism of alloy dissolution is established taking into account the effect of impurities in the alloy on the anodic dissolution process. The conditions for accelerating the anodic dissolution of the AMg alloy in the presence of chlorine ions under the conditions of the “negative differential effect” are determined. The dissolution of the AMg alloy in an alkaline chloride solution has an electrochemical nature, which is based on the electrochemical mechanism of hydrogen reduction with the subsequent process of its diffusion into the gas phase. Chloride ions accelerate the active dissolution of aluminum at current densities of 5 A/dm2 instead of 3 A/dm2 at room temperature and surface roughness of class 3-5 (≈5 μm). The greatest influence on the dissolution rate of the alloy has the concentration of NaOH, the dissolution temperature and the surface cleanliness class. The main technological indicator of the improvement of hydrogen electrosynthesis is the use of anodic depolarization of aluminum, its negative values and, as a consequence, the evolution of hydrogen on both electrodes. The depolarization effect is achieved by dissolving the aluminum alloy instead of the oxygen evolution reaction at the anode. The voltage on the cell is 2 times lower compared to industrial alkaline water electrolysis. This makes it possible to save up to 50% of electricity. The absence of oxygen evolution makes this process safer.

Biosynthesis of Ag@CuO core–shell nanostructures for non-enzymatic glucose sensing using screen-printed electrode

Ag@CuO core shell nanostructures (ACCS NSs) was successfully synthesized using Ocimum tenuiflorum leaf extract when applied for non-enzymatic glucose sensor. SEM, HR-TEM, XRD, UV–vis, and FTIR were used to estimate the structural, optical and morphological properties of ACCS NSs. Cyclic voltammetry and ampherometry were used to determine the electrochemical and electrocatalytic characteristics of 0.2 wt% ACCS NSs with screen-printed electrodes (SPEs) to sense glucose in 0.1 M NaOH solution. Optimum potential was obtained at + 0.4 V of current response with a linear range of 1 to 9.2 mM. In addition, 0.2 wt% ACCS NSs with SPEs had a low detection limit of 0.006 μM and sensitivity of 3763.44 μA mM−1 cm−2. Modified ACCS/SPE electrodes were highly selective for glucose in the presence of chlorine ions, sugars and non-sugar compounds. It could be inferred from the evidence that the ACCS NSs performs effectively in the aspect of non-enzymatic glucose sensing.

Analysis of natural gas hydrate formation in sodium dodecyl sulfate and quartz sand complex system under saline environment

ABSTRACTUnder natural conditions, natural gas hydrate occurs in the pores of porous media found in the sedimentary layer. Thus, the rapid formation and basic properties of the hydrate in the porous medium must be studied. Quartz sand with different particle sizes compounded with Sodium Dodecyl Sulfate solution was used to study the hydrate formation in the system at 275.15 K and 6 MPa under a saline environment. Results were as follows. 1) Methane gas uptake in a saline system with NaCl concentration of 50 mmol was higher than that in pure water. This finding indicated that although the salt is a thermodynamic inhibitor, low concentration of NaCl can promote the formation of hydrates. 2) In the initial stage of the experiment, the rate of hydrate formation in saline environment was significantly higher than that in pure water. After approximately 1 h, the formation rate of hydrate in the compound system decreased under a saltwater environment and was lower than that in the complex system under pure water. 3) The hydrogen bond network inside the high-concentration NaCl solution was seriously damaged. In this case, water molecules cannot easily form a cage structure, and the presence of chlorine ions weakens the stability of a small amount of formed hydrate cage, thereby further inhibiting the formation of hydrates. However, in the low-concentration NaCl system, mass transfer is improved, and the formation of hydrate is promoted because of the weakened hydrogen bonding at the gas–liquid interface.

Effect of polycarboxylate and polyarylate surfactants on corrosion of the steel reinforcement embedded in the concrete

We considered the possibility to inhibit the corrosion of the steel reinforcement embedded in the concrete using different polymeric surfactants, when paired with the passivating and plasticizing chemical additives. Previously [1] the authors proposed the method to form the protective films on the surface of the steel reinforcement embedded in concrete using the polycomponent anticorrosion naphthalene sulfonate superplasticizer based additives. The results of further surveys provided in this article proved, that under the special conditions the polyarylate and polycarboxylate surfactants are capable to keep the steel reinforcement in the passive state in presence of chlorine ions. This is especially relevant, considering the fact, that the polymer additives intended for plasticization of concrete are more widely used for the manufacturing of the monolithic and prefabricated reinforced concrete structures. In the same time Deicing agents having in its composition chlorine ions, are widely used for deicing of roads in different countries. Chlorine ions adversely affect the reinforcement of concrete artificial structures in transport. the corrosion of metals incurs huge losses, the global cost is $ 2.5 trillion, equivalent to 3.4% of world gross domestic product (GDP) for 2013[2]. In 1993, the United States spent 20 billion dollars on the repair of reinforced concrete bridges only because of the impact of chlorides[3].

Effect of Chlorine Ion on the Corrosion of 316L Austenitic Stainless Steel

In this study corrosion resistance of 316L stainless steel has been investigated in a solution containing different percentages of hypochloric solution. In order to examine the rate and mechanism of the occurrence of pitting corrosion in this steel, various corrosion tests have been used. In addition, the locale of the pitting corrosion has been examined by scanning electron microscope. Results show that the presence of chlorine ion with the increase of cathodic reaction rates cause to increase the likelihood of pitting corrosion in 316L steel.

A miniaturized injection-moulded flow-cell with integrated conducting polymer electrodes for on-line electrochemical degradation of azo dye solutions

This study investigates the effectiveness of a novel micro electrochemical flow-cell containing carbon fiber electrodes for the degradation of Azo dye solutions. The flow-cell was fabricated by an injection moulding technique, integrating three electrodes system design using an overmoulding procedure. All electrodes were fabricated from carbon fiber polymer, however, the reference electrode was then coated with Ag/AgCl paste. The effect of the process variables such as flow-rate, NaCl concentration, applied bias current, and solution pH on the degradation process were comprehensively studied. At optimum conditions, complete degradation of the dye was achieved on the bare carbon fiber electrode, without the need for surface modification, in 150min upon the application of 15mA bias current. The degradation process was suggested to follow the indirect oxidation mechanism where the presence of chlorine ions was very essential. Moreover, the micro-flow-cell had proven its stability over the entire operation time, which indicates its practicality for such on-line applications.

Surface controlled generation of reactive radicals from persulfate by carbocatalysis on nanodiamonds

Production of radicals by metal-free catalysis is expected to offer a promising oxidative reaction for remediation of emerging contaminants. In this study, novel metal-free activation of persulfate (PS) on annealed nanodiamonds (ANDs) was investigated, which demonstrated superior performances in decomposition of various pollutants to conventional metal-based catalysis. Comprehensive investigations on the effects of reaction parameters, such as solution pH, reaction temperature, initial phenol concentration, catalyst loading, PS usage, the presence of chlorine ions and humic acid, on phenol degradation were carried out. In addition, nanodiamond (ND) material optimization and reusability were also studied. Electron paramagnetic resonance (EPR) and selective organic degradation unraveled that the PS/AND system may produce both hydroxyl radicals (OH) and sulfate radicals (SO4−), initialized from oxidizing water molecules on the nanodiamond surface. The carbocatalysts served as an excellent electron tunnel to facilitate the charge transfer from water or hydroxide ions to PS, and the oxidized intermediates may play a crucial role in PS activation. Electrochemical analyses in PS oxidant solution and oxygen reduction reaction (ORR) were carried out to understand OO bond activation by the metal-free catalysis. This study provides an environmentally benign and highly efficient oxidative reaction system with reactive radicals along with insights into the metal-free PS activation process.

Effects of Chlorine Ions on the Dissolution Mechanism of Cu Thin Film in Phosphoric Acid Based Solution.

The dissolution mechanisms of Cu thin film were studied with a focus on the effect of chlorine ion concentrations in mixture solutions of phosphoric and nitric acid. The dissolution behaviors of Cu thin film were investigated by using potentio-dynamic curves and impedance spectroscopy with varying chlorine ion concentrations. The copper dissolution rate decreased and as a result of this change, CuCl, salt films formed on the Cu surface in the presence of chlorine ions in the mixture solution. Such behavior was interpreted as being competitive adsorption between chlorine and nitrate ions on the copper surface. The passive oxide film on the Cu surface was further investigated in detail using X-ray photoelectron spectroscopy in both the absence and presence of differing chlorine ion concentrations.

Regularities of electrochemical dissolution of Cu 62 Zn alloy in chloride solutions

The pattern of the electrochemical ionization and passivation of Cu 62 Zn brass in chloride solutions with different compositions is studied. The electrochemical dissolution of Cu 62 Zn alloy is shown to be controlled by ionization of the copper component in the alloy. The dissolution selectivity of the brass Cu 62 Zn components and the modification of the surface of the alloy during electrochemical etching in chloride solutions are studied. The uniform electrochemical dissolution of α-brass in an acid medium was found to occur in the presence of chlorine ions and an Fe3+ oxidizing agent.

Research on the Anti-Sulfate and Chlorine Corrosion Property of Concrete

In this paper wetting-drying cycle in the natural situation and increasing the concentration of sulfate solution is used in the laboratory , in order to accelerate the sulfate corrosion of concrete. The ultrasonic speed of sound on the opposite face is tested by ultrasonic technique regularly in order to reflect the change of concretes strength with the relative dynamic modulus.And at the same time the cube compressive strength test is used to detemine the corrosioned concretes intensity.Though the trend of relative dynamic modulus development which are in four different conditions to explain that the presence of chlorine ions affected the sulfate corrosion on concretes.Although in the compound solution, the corrosion degree should be depended on the concentration of sulfate ions and chloride ions in compound solution.

ENHANCEMENT MECHANISM OF NANOSTRUCTURE FORSTERITE FORMATION RATE BY MECHANICAL ACTIVATION AND AMMONIUM CHLORIDE

The single-phase nanostructure forsterite powder was successfully synthesized by mechanical activation of talc and magnesium carbonate powder mixture followed by annealing in the presence and absence of ammonium chloride. Mechanical activation was used as an efficient method for the optimization of powder properties by means of combination and uttermost homogenization of the powder mass. Besides, the presence of chlorine ion affected the forsterite formation rate via producing smaller particle size during subsequent annealing which is very important in the case of diffusion-controlled reactions. The single-phase nanostructure forsterite powder with crystallite size of about 36 nm was successfully synthesized by 10 h mechanical activation with subsequent annealing at 1000°C for 1 h. While in the presence of chlorine ion, the single-phase nanostructure forsterite powder with crystallite size of about 20 nm could be obtained by 5 h of mechanical activation with subsequent annealing at 1000°C for 2 min.

High-Performance Rubber Sealant for Preventing Water Leaks

Considerable amounts of water are being lost due to leaks. One of the main reasons for experiencing such large water leaks is the premature failure of rubber sealants in valves. Water leaks commonly originate from the presence of chlorine ions in tap water. Here, we demonstrate that the incorporation of surface-modified and highly crystalline carbon nanotubes allows the rubber sealants to maintain their sealing properties without experiencing any distinctive degradation over a wide range of temperature and environmental conditions over their expected lifetime. It is envisaged that environmentally friendly nanotechnology will save huge amounts of energy for purifying and transporting water around the whole world.

Effects of mechanical activation and chlorine ion on nanoparticle forsterite formation

This paper reports the positive effects of chlorine ion on the forsterite formation rate. The influence of mechanical activation of talc and magnesium carbonate mixture on the formation of forsterite structure was studied in the presence of chlorine ion. Mechanical activation increased the contact surface area of the reacting phases as a consequence of intensively reduced particle size, which is very important in the case of diffusion-controlled reactions. Besides, the presence of chlorine ion affected the forsterite formation rate following annealing. The single-phase nanostructure forsterite powder with a crystallite size of about 20 nm was obtained by 5 h of mechanical activation and subsequent annealing at 1000 °C for 2 min in the presence of the chlorine ion.