HCl Acid Solution Research Articles

Shale Creep as Leakage Healing Mechanism in CO2 Sequestration

Experiments on shale specimens targeted creep deformation in order to investigate whether this mechanism could be relied upon to close fractures and stop leakage near injection wells. Uniaxial compression tests were conducted with stress ramp up paused near expected failure stress of the tested shale and additional deformation, interpreted as initial creep deformation, was logged. The tests were repeated on shale samples exposed to HCl acid solutions, simulating expected pH conditions near the well upon exposure to injected CO2. The purpose of the tests was to compare the creep propensity of the material after possible dissolution of load-bearing minerals, to the virgin case. The results show slight enhancement of creep deformation. Exposure to super-critical CO2 on the same shale was carried out on hollow cylinder plugs, with radial closure of the borehole measured under radial stress conditions. Results show a doubling in radial deformation when compared to control tests with brine exposure. Finally, analyses of synchrotron beam tomography images were performed to quantify volume change between shale specimens preserved in oil and specimens exposed to HCl, showing that total volume increased by 9%.

A comparative analysis of the dissolution kinetics of lead from low grade oxide ores in HCl, H2SO4, HNO3and citric acid solutions

In this study, the dissolution of lead from a low grade oxide ore in HCl, H2 SO4 , HNO3 and citric acid solutions was investigated in a batch reactor employing parameters expected to affect the dissolution rate such as stirring speed, liquid to solid (L/S) ratio, temperature and acid concentration. The maximum recovery of lead were obtained to be 85.52% after 90 min with inorganic acids at 20%, 80 °C, 500 rpm and L/S = 20 ml/g, while the maximum dissolution was determined to be 73.81% with citric acid. Also, H2 SO4 was not able to dissolve lead from low grade oxide ore. The dissolution kinetics of lead was examined according to heterogeneous models. It was found that the dissolution rate was controlled by the diffusion through the fluid film (1 − (1 − x )2/3 ) in HNO3 and citric acid solutions with the activation energies of 7.71 and 11.62 kJ/mol, respectively. Additionally, when the dissolution was performed in the presence of HCl, the surface chemical reaction in an initial stage (0–30 min) and fluid film diffusion in a second stage (after 30 min) were the rate controlling steps. The activation energies of these sequential steps were determined to be 60.94 and 28.24 kJ/mol, respectively.

Decyltrimethylammonium Bromide Micelles in Acidic Solutions: Counterion Binding, Water Structuring, and Micelle Shape.

Wide-angle neutron scattering experiments combined with empirical potential structural refinement modeling have been used to study the detailed structure of decyltrimethylammonium bromide micelles in the presence of acid solutions of HCl or HBr. These experiments demonstrate considerable variation in micelle structure and water structuring between micelles in the two acid solutions and in comparison with the same micelles in pure water. In the presence of the acids, the micelles are smaller; however, in the presence of HCl the micelles are more loosely structured and disordered while in the presence of HBr the micelles are more compact and closer to spherical. Bromide ions bind strongly to the micelle surface in the HBr solution, while in HCl solutions, ion binding to the micelle is similar to that found in pure water. The hydration numbers of the anions and extent of counterion binding follow the predictions of the Hofmeister series for these species.

Preparation of high stable core/shell magnetic nanoparticles and application in Bacillus thuringiensis Cry1Ac proteins detection

The silicon coated Magnetic nanoparticles (MNps) were prepared and applied to the genetically modified detection for Cry1Ac protein. TEM observations showed the bare MNps were in the size of 3–5nm and the silicon coated core/shell MNps were in the range of 30–60nm 1M HCl acidic solution was used to test the chemical stability of the resultant MNps and results showed the coated MNps were very stable in the acid environment even after 12h. Cy3 labelled IgG tests showed that the probe on the MNps was kept the bioactivity in the immunoassays. MNps based detection results showed that this analytical strategy had similar linear relation which R=0.995 with the commercial ELISA kit. The MNps based detections were reliable for the Cry1 Ac protein in the linear range from 0.1pg/L to 1.0mg/L, and showed better performance in the low concentration of analyte. This study provides a promising technique to detect the Cry1Ac protein with high sensitivity in the examination of the GM products which is of importance in food safety.

Sintering Preparation and Release Properties of K2MgSi3O8 Slow-Release Fertilizer Using Biotite Acid-Leaching Residues as Silicon Source

The sintering preparation of K2MgSi3O8 at 700–950 °C for 2 h using biotite acid-leaching residues, K2CO3, and Mg(OH)2 as the starting materials was investigated in this research. The sintered samples were characterized by X-ray diffraction, X-ray fluorescence, Fourier transformation infrared spectrometry, and scanning electron microscopy. The results indicated that the hexagonal kalsilite-like K2MgSi3O8 with an irregular blocky morphology was prepared at 900 °C for 2 h. The solubility of K2MgSi3O8 in HCl and citric acid solution shows that the extraction of K2O is 38.94% in 0.50 M HCl and 23.58% in 0.10 M citric acid solution, respectively. For the optimal sample dispersed in distilled water, the accumulative release of K2O is 6.06% in the first day and 44.90% in 28 days, which reaches the Chinese national standard of slow-release fertilizer. All the results indicate that the as-prepared K2MgSi3O8 is appropriate for application as slow-release fertilizers supplying nutritional components K, Mg, and Si for...

Towards carboxylic acid-functionalized aniline monomers: Chemical synthesis, electropolymerization and characterization

Polyaniline is one of the most studied conducting polymers because of its high stability and interesting combination of redox and proton doping properties. Moreover, it is possible to use the amino group of polyaniline to graft a substituent to obtain polyaniline derivatives. In the present study, aniline monomers were functionalized by an alkyl chain terminated by a carboxyl group at the N-position of the monomers in an attempt to obtain a series of carboxylic acid-functionalized polyanilines. The electro-oxidation of the modified aniline monomers was studied in HCl and H3PO4 acidic solutions with potentiodynamic and potentiostatic methods. The influence of the nature of the solvent and the length of the grafted alkyl chain on the thickness, morphological features and wettability of the carboxyl-functionalized polyaniline films was studied. In particular, the nature of the acid used strongly impacted the film properties leading to thinner, smoother, more hydrophilic, more adhesive and more homogeneous films when the electropolymerization was performed in phosphoric acid solutions.

Synthesis of nanocrystalline TiB2 powder from TiO2, B2O3 and Mg reactants through microwave-assisted self-propagating high-temperature synthesis method

In this research work, microwave-assisted self-propagating high-temperature synthesis (SHS) process was employed for the fabrication of titanium diboride (TiB2) compound from TiO2–B2O3–Mg mixtures. Thermodynamic evaluations of this system and its relevant subsystems revealed that TiB2–MgO composite powder can be easily produced by a SHS reaction. However, experimental results of a TiO2 : B2O3 : 5Mg mixture heated in a domestic oven showed the formation of some intermediate compounds such as Mg3B2O6, presumably due to some degree of Mg loss. The optimum amount of Mg in TiO2 : B2O3 : xMg mixtures, yielding the highest amount of TiB2 phase, was found to be around 7 mol, i.e., 40 mol% more than the stoichiometric amount. Experimental results revealed that a pure TiB2 compound could be obtained by leaching the unwanted by-products in an HCl acid solution. Scanning electron microscopic observations and Scherrer calculations showed that the produced TiB2 contains sub-micron (150–200 nm) particles, where each particle consists of a number of nanosized (32 nm) crystallites.

Adsorption Aspects, Inhibitory Properties and a Study of Surface Corrosion of Carbon Steel in Acidic Media

The impact of cupral compound on steel in presence of deaerated 0.25 M H2SO4 and 0.5M HClacidic solutions at 298.15K was examined by employing electrochemical measurements. It has been observed that the corrosion efficiency increased by increasing of cupral concentration of the corrosion inhibitor and this enhanced the inhibitory action as mixed type inhibitor. Several different adsorption models were examined which indicate the adsorption of cupral compound as inhibitor on the carbon steel electrode surface follows the Langmuir isotherm equation. The thermodynamic factors governing adsorption, as well as the parameters of kinetics corrosion have been estimated. The role of nanosilica has been observed to reduce the values of current density of corrosion process and this was confirmed by study the surface morphology of electrode via SEM-EDX and AFM techniques by formation a protective layer on carbon steel electrode.

English

The inhibitory potentials of ethanolic extracts and four fractions of the stem bark of Ficus asperifolia – Miq. for the corrosion of mild steel were assessed using weight loss method, Fourier atomic absorption spectroscopy, scanning electron microscopy (SEM). The effects of varying immersion period, concentration of the inhibitors and temperatures for mild steel corrosion in 5 M HCl acid solution were carried out. A detailed kinetic reaction, thermodynamic (Ea, ∆H, ∆S) and adsorption isotherm studies were obtained. The crude extract of F. asperifolia (EFA) has the highest inhibition efficiency of 55%. The inhibitory efficiency of the four fractions of F. asperifolia (EFA) compared with the crude extract was in the order ethyl acetate > n-hexane > butanol > EFA > Aqueous. The inhibition efficiency was found to increase with increase in the extracts concentration but decreased with temperature. Corrosion rate increases with time but decreases with extracts concentration. The kinetic studies of the data followed a first order reaction. Thermodynamic studies revealed that corrosion inhibition may be due to spontaneous mixed adsorption of the plant constituents on the metal surface. Experimental data were fitted to Langmuir, Freundlich and Temkin adsorption isotherms. The plant investigated showed a good potential for green corrosion inhibitors. Investigation of phytochemical constituents showed that the extracts contain alkaloids, flavonoids, saponins, tannins anthraquinones and reducing sugars. Key words: Inhibitory efficiency, corrosion rate, adsorption isotherm.

Adsorption and corrosion inhibition properties of thiocarbanilide on the electrochemical behavior of high carbon steel in dilute acid solutions

The inhibition performance of thiocarbanilide on the electrochemical corrosion behavior of high carbon steel in 1M H2SO4 and HCl acid solutions was studied through weight loss method and potentiodynamic polarization test. Data obtained showed that the organic compound performed effectively in acid solutions at all concentrations with an average thiocarbanilide inhibition efficiency above 70% in H2SO4 acid and 80% in HCl acid from weight loss and potentiodynamic polarization test respectively. Results from corrosion thermodynamic calculations showed that the adsorption of thiocarbanilide onto the steel was through chemisorption mechanism whereby the redox electrochemical process responsible for corrosion and the electrolytic transport of corrosive anions were simultaneously suppressed. Statistical derivations through ANOVA analysis confirm that the influences of both the inhibitor concentration and exposure time on inhibition efficiency values are negligible. Adsorption of the compound was determined to obey the Langmuir and Frumkin isotherm model.

Treatment of copper(II) containing wastewater by a newly developed ligand based facial conjugate materials

A sensitive and selective colorimetric method for simultaneous detection and removal of copper (Cu(II)) ion from contaminated water samples was developed based on the functional ligand embedded mesoporous conjugate materials. The synthesized material’s characterization was also presented. The conjugate materials exhibited an obvious color change from colorless to dark yellow in the presence of Cu(II) ion according to the pH values. Also, the Cu(II) ion were detected and removed through naked-eye. The prepared material exhibited significant color change upon addition of Cu(II) ion even in the presence of other competing ions, and the limit of detection was calculated to be 0.15μg/L. Excellent selectivity toward Cu(II) ion was observed due to a specific complex formation between Cu(II) ion and organic ligand of the conjugate materials. In Cu(II) adsorption operation, several affecting factors, including the solution pH, contact time, initial Cu(II) ion concentration, foreign ions and reuses were investigated. The results showed that the conjugate materials exhibited excellent adsorption capacity and adsorption equilibrium was reached rapidly. The adsorption results were well fitted with Langmuir adsorption isotherms and the maximum adsorption capacity by the materials for Cu(II) ion was 174.76mg/g. We claimed from this study that Cu(II) could be successfully detected and removed by the adsorption method developed in the current work. The present work is obviously much simpler and greener than the conventional comprising multistep processes. The results demonstrated that Cu(II) ion loaded conjugate materials was effectively regenerated using HCl acid solution, and the regenerated materials was repeated to use many cycles without significant capacity loss, indicating the good stability of prepared conjugate materials.

Relative Order of Sulfuric Acid, Bisulfate, Hydronium, and Cations at the Air-Water Interface.

Sulfuric acid (H2SO4), bisulfate (HSO4(-)), and sulfate (SO4(2-)) are among the most abundant species in tropospheric and stratospheric aerosols due to high levels of atmospheric SO2 emitted from biomass burning and volcanic eruptions. The air/aqueous interfaces of sulfuric acid and bisulfate solutions play key roles in heterogeneous reactions, acid rain, radiative balance, and polar stratospheric cloud nucleation. Molecular-level knowledge about the interfacial distribution of these inorganic species and their perturbation of water organization facilitates a better understanding of the reactivity and growth of atmospheric aerosols and of the aerosol surface charge, thus shedding light on topics of air pollution, climate change, and thundercloud electrification. Here, the air/aqueous interface of NaHSO4, NH4HSO4, and Mg(HSO4)2 salt solutions as well as H2SO4 and HCl acid solutions are investigated by means of vibrational sum frequency generation (VSFG) and heterodyne-detected (HD) VSFG spectroscopy. VSFG spectra of all acid solutions show higher SFG response in the OH-bonded region relative to neat water, with 1.1 M H2SO4 being more enhanced than 1.1 M HCl. In addition, VSFG spectra of bisulfate salt solutions highly resemble that of the dilute H2SO4 solution (0.26 M) at a comparable pH. HD-VSFG (Im χ((2))) spectra of acid and bisulfate salt solutions further reveal that hydrogen-bonded water molecules are oriented preferentially toward the bulk liquid phase. General agreement between Im χ((2)) spectra of 1.1 M H2SO4 and 1.1 M HCl acid solutions indicate that HSO4(-) ions have a similar surface preference as that of chloride (Cl(-)) ions. By comparing the direction and magnitude of the electric fields arising from the interfacial ion distributions and the concentration of each species, the most reasonable relative surface preference that can be deduced from a simplified model follows the order H3O(+) > HSO4(-) > Na(+), NH4(+), Mg(2+) > SO4(2-). Interestingly, contrary to some other near-neutral salt solution interfaces (e.g., chlorides and nitrates), cation-specific effects are here overshadowed by hydronium ions.

Corrosion Behavior and Microstructure of Borided Tool Steel

In the present study, the corrosion behaviors of borides formed on cold work tool steel have been investigated in a 4% M HCl acid solution. Boriding was performed in a solid medium consisting of Ekabor-II powders at 850 and 950°C for 6 h. The boride layer was characterized by SEM, EDS, XRD and the hardness tester. XRD analysis of boride layers on the surface of the samples revealed the existence of FeB, Fe2B, CrB, Cr2B and MoB compounds. Depending on the chemical composition of substrates and boriding time, the boride layer thickness on the surface of the steel ranged from 13.14 μm and 120.82 μm. The hardness of the boride compounds formed on the surface of the samples ranged from 1806 to 2342 HV0,05, whereas Vickers hardness values of the untreated the samples was 428 HV0,05. The corrosion resistance of the borided steels was higher compared with that of the unborided steels. The borided steels increased the corrosion resistances of the steels 8-17- fold.

Synchrotron-based XPS studies of AlGaN and GaN surface chemistry and its relationship to ion sensor behaviour

Abstract Soft X-ray photoelectron spectroscopy was used to investigate the fundamental surface chemistry of both AlGaN and GaN surfaces in the context of understanding the behaviour of AlGaN/GaN heterostructures as chemical field-effect transistor (CHEMFET) ion sensors. AlGaN and GaN samples were subjected to different methods of oxide growth (native oxide and thermally grown oxide) and chemical treatment conditions. Our investigations indicate that the etching of the oxide layer is more pronounced with AlGaN compared to GaN. Also, we observed that chloride ions have a greater tendency to attach to the GaN surface relative to the AlGaN surface. Furthermore, chloride ions are comparatively more prevalent on surfaces treated with 5% HCl acid solution. The concentration of chloride ions is even higher on the HCl treated native oxide surface resulting in a very clear deconvolution of the Cl 2p 1/2 and Cl 2p 3/2 peaks. For GaN and AlGaN surfaces, a linear response (e.g. source-drain current) is typically seen with variation in pH of buffered solutions with constant reference electrode voltage at the surface gate; however, an inverted bath-tub type response (e.g. a maximum at neutral pH and lower values at pH values away from neutral) and a general tendency to negative charge selectivity has been also widely reported. We have shown that our XPS investigations are consistent with the different sensor response reported in the literature for these CHEMFET devices and may help to explain the differing response of these materials.

Study on the Pyrolysis Kinetics of HCl-Pretreated Soybean Stalk

To study the influences of the acid-washing on the characteristics of soybean stalk pyrolysis , and search the high-efficiency catalyst for biomass pyrolysis, pyrolysis experiments of soybean stalk pretreated by 0.1mol/L HCl acid solution were performed by nonisothermal thermogravimetric analysis (TGA) at five different heating rates. The results showed the pyrolysis process of HCl-washed soybean stalk can be separated into four stages (water loss, depolymeri-zation and vitrification, thermal decomposition, and carbonization). At the same heating rate, the maximum pyrolysis rate of HCl-washed is larger than untreated soybean stalk, but the corresponding temperature is higher. All the DTG (differential thermogravimetric) curveas appear a smaller shoulder peak respectively. With the heating rate increasing, the main pyrolysis zone of the TG (thermogravimetric) and DTG curves move to the high-temperature direction, and the maximum pyrolysis rate and its corresponding temperature increase too. HCl-wahsed makes the weight loss rate of the final temperature increase 5% approximately. The value area of activation energy of the main pyrolysis area is 140.19~174.59 kJ/mol calculated by the method of Ozawa. The Šatava method inferred the most possible mechanism function of HCl-wahsed soybean stalk is Zhuralev-Lesakin-Tempelman equation, which is three-dimensional diffusion.

The Synergistic Effect of Thiourea and Surfactants on Corrosion Inhibition of Stainless Steel-316 in Hydrochloric Acid

Corrosion and scaling are the common problems to all the industries. A remedy of these problems was sought out through chemical treatment: indigenously available raw materials including thiourea, surfactants (cationic, anionic and nonionic containing pre, critical and post micellar concentration). Evaluation of corrosion inhibition properties stainless steel 316 by thiourea based inhibitor and its synergistic effect with cationic cetyl tri-methyl ammonium bromide (CTAB), anionic sodium dodecyl sulphate (SDS) and nonionic triton X-100 have been carried out by weight loss method as a function of concentration of thiourea and surfactants. These materials were applied to the coupons of stainless steel 316 in different acidic concentration. Corrosion rates were calculated using weight loss method. Excellent results were achieved regarding corrosion inhibition in the presence of thiourea and surfactants assuring the better performance of these chemicals. The results showed that corrosion rate was decreased from 90 mpy to 12.1 mpy after 720 hours by the addition of 200ppm thiourea in critical micellar concentration of SDS in 3M HCl acid solution.

Synthesis and characterization of sulphanilic acid–dithiooxamide–formaldehyde terpolymer resin for adsorption of nickel ions from waste water

A new chelating terpolymer resin of sulphanilic acid–dithiooxamide–formaldehyde (SDTOF) was synthesized. Dithiooxamide–formaldehyde (DTOF) was prepared by the reaction of dithiooxamide and formaldehyde. These resins were characterized using Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, and scanning electron microscopy. Chelating resins beads were applied for adsorption of nickel (II) ions by batch and column techniques. Sorption experiments were performed by varying pH, agitation time, sorbent dosage and initial concentration of nickel (II) ion solution. SDTOF and DTOF resins showed adsorption capacity of 188.3 and 99.8 mg g−1, respectively. Nickel adsorption isotherms data were fitted to Langmuir isotherm. Kinetic studies showed the adsorption process followed pseudosecond‐order rate model. Desorption of Ni(II) ions was done using 0.1 M HCl, HNO3, and ethylenediamine tetraacetic acid solutions. The reusability of SDTOF and DTOF resins for the removal of Ni(II) ions was also determined after 10 sorption−desorption cycles. POLYM. ENG. SCI., 55:163–172, 2015. © 2014 Society of Plastics Engineers

Corrosion Inhibition Effects and Adsorption Characteristics of Ethanol Extract of King Bitters Root (Andrographis paniculata) on Mild Steel in Hydrochloric and Tetraoxosulphate (VI) Acid Media

The corrosion inhibition performance of ethanol extract of Andrographis paniculata (King Bitter) root (EEAPR) on the corrosion of Mild Steel (MS) in 1.0 M HCl and H2SO4 acid solutions at 303K and elevated temperatures of 313, 323 and 333K was investigated and compared. The experimental work was performed by the use of weight loss and hydrogen evolution techniques. The results indicate that the extract inhibit the corrosion of mild steel in both acid media. However, the EEAPR exhibits higher maximum inhibition efficiency of 98.9 % in HCl than in H2SO4 (95.0 %) at 5.0 g/L. Inhibition efficiency was found to increase with increasing concentration of extract in both acid media but decreased with rise in temperature. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of extract on the MS sample in both acid media was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters.Â

The effect of extra framework species and acid properties of dealuminated zeolitic support on the catalytic behavior of palladium in n-hexane isomerization reaction

Isomerization of n-hexane was carried out over palladium based catalysts prepared by aqueous ion exchange with dealuminated NaY-zeolite support. The dealumination was realized using acid solutions of HNO3, HCl and H2SiF6 with different concentrations. The catalysts were characterized by nitrogen physisorption, XRD, 27Al and 29Si-MAS-NMR, the NH3-TPD, the H2-TPR and DRIFT. The catalytic reaction was performed in the temperature range between 498 and 548 K. The results showed that the isomer selectivity and catalytic activity of catalysts increased with increasing the Si/Al ratio of the support and, specially, with the presence of extra framework species which control the active Bronsted and Lewis acid sites.

Effect Formazan of Benzaldehyde as Corrosion Inhibitor on Preventing the Mild Steel Corrosion in Acidic Medium

The effect of formazan of benzaldehyde (FB) on the corrosion of mild steel in acidic media (1 M HCl and 2 M HCl) has been investigated using weight loss measurements, electrochemical studies and surface analysis. These studies have also shown that formazan of benzaldehyde is a good inhibitor for mild steel in 1 M HCl and 2 M HCl acid solutions at room temperature in 2 h. In 1 M HCl the inhibition efficiency was high when compared to 2 M HCl acid solutions. The surface analysis also confirms the corrosion inhibition of the mild steel by the inhibitor (FB).