Weak Acid Solution Research Articles

Framework Integrated with Flow Cell Experiments and Simulations for Understanding Etching in Chemical Conversion Treatments

In this study, a new framework integrates simulations and flow cell experimentation to quantitatively understand the mechanism of chemical treatment reactions. Using this framework, the mechanisms of etching reactions induced by weak and strong acids were specifically investigated. A flow cell system experiment was developed for the etching experiment. Two acids (HNO3 and HF) were used, along with HNO3 without electrolytes. Average flow velocities were measured, and the molar flux of Fe2+ ions was determined by sampling the solution passing through the flow cell and measuring the iron content by using inductively coupled plasma. A concentration field simulation of the etching reaction in the flow cell was conducted. The concentration field within the boundary layer was visualized to understand the mechanism of H+ ion supply to the metal surface. In the case of weak acid solutions, H+ ions are primarily supplied by dissociation. In contrast, they were supplied by diffusion in strong acid solutions. A boundary layer formed within 100 μm from the metal surface. The experimental and simulated molar flux of Fe2+ ions were compared. The molar flux attributed to weak acid etching was more than 10 times that attributed to strong acids. The reaction rate constant of the H+ reduction reaction was evaluated through a parameter study. The influence of spectator ions on the etching process was investigated. An experiment was conducted to compare the etching of iron plates using HNO3 solutions with different concentrations of spectator ion. The results confirmed that the higher the concentration of the spectator ion, the greater the etching amount. Numerical analysis revealed that the electric field in the electric migration term acts in a direction that impedes the movement of H+ ions to the metal surface. While it is already known that electric migration inhibits electrode reactions, this study enabled its quantitative visualization and evaluation.

A predictive model for corrosion of carbon steel exposed to organic acids: Theory and validation in formic, azelaic and citric acid

Organic acids can severely corrode metals, despite rarely reaching particularly low pH values. The mechanisms underlying the corrosion process in the presence of organic acids can be different and more complex with respect to the ones in the presence of strong acids. Since organic acids are commonly found in several industrial environments, they pose a serious threat that needs to be carefully addressed and investigated. Throughout the years, many research efforts have been put towards predictive modeling of corrosion. The Tafel-Piontelli model aims at becoming a universal and versatile model for acidic corrosion, able to adapt to different situations and predict corrosion rates of active metals exposed to all kinds of acidic environments. The model foundations are grounded in the principles of the corrosion process, regulated by the Tafel law. The efficacy of the model was tested on carbon steel samples immersed in solutions of weak acids with increasing proticity — formic, azelaic, and citric acid — at temperatures ranging from 20°C to 60°C and pH values from 3 to 4. The validation analysis was conducted using two primary tests: mass loss tests to assess corrosion rates and potentiodynamic polarization tests to determine the kinetic parameters of the cathodic and anodic reactions involved in the corrosion process. The results from the experiments are promising, confirming and extending the predictive capabilities of the model to the case of organic acids. These findings have broad implications for improving safety and durability in industrial applications where organic acids are prevalent, highlighting the model’s potential to significantly enhance preventive strategies and material selection.

In-situ poly(hexahydrotriazine) gels temporary plugging agent suitable for high-temperature reservoirs: Regulation by inorganic chloride salts

A new acid-soluble in-situ temporary plugging agent suitable for high-temperature reservoirs was developed. By regulating the aldehyde-amine condensation reaction using inorganic chlorine salts, the poly(hexahydrotriazine) gels (PHT gels) exhibit good plugging performance and high-temperature resistance and can be degraded in weak acid solutions without residue. Results show that inorganic chlorine salts have a regulating effect on the gelling time of the gelant. Without the salt or the addition of monovalent chlorine salt, the gelant gels at room temperature but does not form a gel at high temperatures. After adding divalent or trivalent inorganic salts, PHT gels are formed at high temperatures, and their gelling time increases with the increase in salt content. Mechanical compression experiments show that the compression resistance of PHT gels is almost unchanged after exposure to high temperature (140 °C) and high salt (200 g/L NaCl and 10 g/L CaCl2). Displacement experiments show that PHT gels have excellent plugging performance with a plugging rate of more than 98.50% and a maximum plugging pressure of 5.34 MPa under the high temperature and high-salt conditions mentioned above. In addition, a hydrochloric acid solution with pH ≤ 5 can achieve residue-free breakage of PHT gels. The gel-breaking fluid has a high surface activity to facilitate flowback and a core unblocking rate of more than 100% after gel-breaking, making the reservoir permeability recoverable. The plugging and acidolysis ability of PHT gels make them excellent in-situ temporary plugging agents. This study aims to provide insights into the preparation of PHT gels and their use in high-temperature reservoirs.

Elemental distributions of solid waste collected from the germanium extraction process.

The solid waste produced from the germanium extraction process has attached much attention to its potential germanium sources. However, the elemental distribution of solid waste is still unclear. Therefore, the solid waste was studied using a sequential extraction procedure and characterizations including XRD, FTIR, XPS, SEM-EDS, and XAFS. It has been found that Ca, S, Fe, and Si could present crystal occurrence forms such as calcium sulfate, iron oxide hydroxide, or quartz. Furthermore, Si and Al can form a certain amount of amorphous substance. Accordingly, the sequential leaching results tell that Ca and S can be mostly leached out in pure water or weak acid solution, and more than 50% of Fe, Al, and Si were leached out in the reducible or oxidizable environment. Additionally, a part of S could be associated with Pb, generating a mostly Pb-bearing sulfate structure. Most of Zn was leached out from the reducible step, and only a very small part of Zn presented in the residual state, indicating that the majority of Zn might exist in an oxidation state and a small amount of Zn is associated in the amorphous phase. In terms of Ge, As, and Cr, almost all of them existed in the residual state. Ge should be in the occurrence of Si/Al amorphous structure. Similarly, Cr should be most likely to associate with silicates. Furthermore, As is mainly associated with iron mineral through the formation of the binuclear bidentate corner-sharing complex.

Non-chromatographic speciation analysis of antimony in water samples assisted by vinylimidazole-based polymeric sorbent

A functional polymeric material was synthesized via precipitation copolymerization of vinylimidazole and trimethylolpropane trimethacrylate and used as а sorbent for selective separation and determination of Sb(V) and Sb(III). The extraction efficiency of the newly synthesized material toward Sb(III) and Sb(V) was studied in batch mode. In weakly acidic aqueous solutions, at pH 5 – 6, Sb(V) was entirely retained on the polymeric sorbent, while Sb(III) remained in the supernatant. Quantitative elution of Sb(V) was accomplished with 1 mM diammonium hydrogen citrate for 30 min. An analytical procedure for non-chromatographic speciation and determination of inorganic antimony was developed. Concentrations of the target Sb(V) and the non-extractable Sb(III) were measured by ICP-OES with limits of quantitation of 4.2 μg/l and 3.4 μg/l, respectively. The method showed good accuracy, high precision, and applicability to low-mineralized waters, enabling up to 25-fold preconcentration of Sb(V).

Determination of corrosion product film on pure Mg in Cl− environment using XPS etching

Abstract X-ray photoelectron spectroscopy (XPS) combined with Ar ion etching was used to analyse the surface film of pure Mg at different depth after immersion in 3.5 % NaCl solution for 10 min. The XPS spectra of specimen surface showed that the corrosion products are mainly made up of Mg(OH)2 and Mg2Cl(OH)3·xH2O. The formation process of Mg2Cl(OH)3 is the reaction of Mg(OH)2 and Cl− and H+ in weak acidic solutions. The XPS results indicated that the intensities of Mg2Cl(OH)3·xH2O decreased with the increase of etching time from 0 s to 4680 s. It is confirmed that the edge of Mg(OH)2 protrudes outward and then splits into Mg2Cl(OH)3 when Cl− attacks the Mg(OH)2 films, so the Mg2Cl(OH)3 attached to Mg(OH)2. Meanwhile, coupling the scanning electron microscope (SEM) and transmission electron microscopy (TEM) with the XPS to analyze the corrosion mechanism. Furthermore, the results displayed that the XPS combined with Ar ion etching is a good characterization method to understand the reaction of corrosion products.

Enhanced Versatility in Thorium Removal: Mesoporous Silica-Coated Magnetic Nanoparticles Functionalized by Phenanthroline Diamide as a Selective Adsorbent.

In order to promote the sustainable development of nuclear energy through thorium (Th(IV)) recycling, we synthesized SiO2-coated magnetic functional nanocomposites (SiO2@Fe3O4) that were modified with 2,9-diamide-1,10-phenanthroline (DAPhen) to serve as an adsorbent for Th(IV) removal. SiO2@Fe3O4-DAPhen showed effective Th(IV) adsorption in both weakly and strongly acidic solutions. Owing to its porous structure that facilitated rapid adsorption kinetics, equilibrium was achieved within 5 and 0.5 min at pH 3 and 1 mol L-1 HNO3, respectively. In weakly acidic solutions, Th(IV) primarily formed chemical coordination bonds with DAPhen groups, while in strongly acidic solutions, the dominant interaction was electrostatic attraction. Density functional theory (DFT) calculations indicated that electrostatic attraction was weaker compared to chemical coordination, resulting in reduced diffusion resistance and consequently faster adsorption rates in strongly acidic solutions. Furthermore, SiO2@Fe3O4-DAPhen exhibited a high adsorption capacity for Th(IV); it removed Th(IV) through chelation and electrostatic attraction at pH 3 and 1 mol L-1 HNO3, with maximum adsorption capacities of 833.3 and 1465.7 mg g-1, respectively. SiO2@Fe3O4-DAPhen also demonstrated excellent tolerance to salinity, adsorption selectivity, and radiation resistance, thereby highlighting its practical potential for Th(IV) removal in diverse contaminated water sources. Hence, SiO2@Fe3O4-DAPhen represents a promising choice for the rapid and efficient removal of Th(IV).

Synthesis of uniformly ordered single-crystalline TiO2 nanorods on flexible Ti substrate

With high conductivity and ionic mobility, one-dimensional (1D) titanium dioxide (TiO2) nanoarrays have attracted great interest in the photoanode of solar cells and the cathode of lithium-ion/sodium-ion batteries. However, the synthesis of TiO2 nanoarrays often requires highly toxic or corrosive solution circumstances. Meanwhile, the case that most TiO2 nanoarrays are grown on rigid conductive substrate can’t satisfy the demand for application in the space of complex shape. In this work, we developed a simple method to prepare highly ordered single crystalline rutile TiO2 nanorod arrays with high density on flexible metal Ti substrate in relatively weak acid solution, and the orientation of the nanorods were more uniform than those by other means ever before. Based on detailed analysis, an ion-assisted and concentration-limited epitaxial growth mechanism by H+ and is proposed for this uniformly ordered rutile TiO2 nanorod array. This work can promote the research and application of flexible solar cells and lithium-ion batteries, especially their integration.

High efficiency and rapid treatment of naproxen sodium wastewater by dielectric barrier discharge coupled with catalysis

Pharmaceutical wastewater has the characteristics of high organic concentration and poor biodegradability, which will cause serious environmental pollution when discharged into water bodies. In this work, naproxen sodium was used to simulate pharmaceutical wastewater by dielectric barrier discharge technology. The effects of dielectric barrier discharge (DBD) and combined catalysis on the removal of naproxen sodium solution were studied. The removal effect of naproxen sodium was affected by discharge conditions, including discharge voltage, frequency, air flow rate and electrode materials. It was found that the highest removal rate of naproxen sodium solution was 98.5%, when the discharge voltage was 7000V, the frequency was 3333Hz, and the air flow rate was 0.3 m3/h. In addition, the effect of the initial conditions of naproxen sodium solution was studied. The removal of naproxen sodium was relatively effective at low initial concentrations as well as under the condition of weak acid or near-neutral solution. However, the initial conductivity of naproxen sodium solution had little effect on the removal rate. The removal effect of naproxen sodium solution was compared by using catalyst combined with DBD plasma and DBD plasma alone. x%La/Al2O3, Mn/Al2O3 and Co/Al2O3 catalysts were added. The removal rate of naproxen sodium solution reached the highest after adding 14%La/Al2O3 catalyst, which played the best synergistic effect. The removal rate of naproxen sodium was 18.4% higher than that without catalyst. The results showed that the combination of DBD and La/Al2O3 catalyst may be a promising method to remove naproxen sodium efficiently and quickly. And this method is a new attempt to treat naproxen sodium.

Экологически безопасные направления использования отходов добычи угля как техногенного сырья алюминия

Purpose: Substantiation and development of new environmentally safe trends for utilization of dump rock of Donbass coal mines as technogenic aluminum deposits. To investigate mineralogical and chemical composition of dump rock samples of metamorphism varying degrees in order to substantiate the possibility of their processing as technogenic poor aluminum raw material. To conduct the experiments on chemical and biochemical (bacterial) leaching of fluid (soluble) aluminum compounds from dump rock samples. Methods: Analysis of chemical transformations and technogenic mineralogy in stored dump rock. Chemical and biochemical acid leaching of aluminum sulfate salts from dump rock of metamorphism varying degrees was carried out. Results: It has been established that according to the content of bauxites, the dump rock of Donbass coal mines can be attributed to poor aluminum raw material. Method of acid chemical leaching of soluble aluminum compounds with sulfuric acid solutions of various concentrations is proposed and effective leaching with weak acid solutions is proved. Method of biochemical (bacterial) leaching of aluminum salts is substantiated and vindicated. Practical significance: It is testified that environmental friendliness and cost–effectiveness of the process of closely-grouped biochemical leaching is ensured by the fact that the main reagent — sulfuric acid - is formed naturally as a result of bacteria vital functions and the process does not need additional technological units for acid production.

A photoelectrochemical sensor for ultrasensitive dopamine detection based on composites of BiOI and Au-Ag nanoparticles

A photoelectrochemical dopamine sensor based on BiOI and AuAgNPs nanoparticles modified indium tin oxide (ITO) electrode was prepared successfully. The noble metal material AuAg significantly improved the shortcomings of poor surface conductivity and easy recombination of photogenerated electron holes in BiOI. The prepared electrode generated a significantly enhanced and stable photocurrent signal under Xe lamp irradiation. In addition, in weak acidic electrolyte solution, dopamine molecules were protonated and preferent existed in the form of cations, which were easily attracted by electrostatic and adsorbed on the surface of negatively charged AuAgNPs. As an electron donor, DA is vulnerable to oxidation to DA+ by BiOI holes, resulting in an increased anodic photocurrent. The detection limit was 0.3 pM (S/N = 3) and the dopamine concentration exhibited a nice linear relationship between 1 pM and 0.1 μM under ideal circumstances. The dopamine photoelectrochemical sensor shown strong sensitivity, a broad linearity range, and good selectivity against potential uric acid and ascorbic acid interference. This work provides a promising PEC detection platform for the detection of small and medium-sized molecules in biological analysis.

High-Pressure Bulk Synthesis of InN by Solid-State Reaction of Binary Oxide in a Multi-Anvil Apparatus.

We present a new method to synthesize bulk indium nitride by means of a simple solid-state chemical reaction carried out under hydrostatic high-pressure/high-temperature conditions in a multi-anvil apparatus, not involving gases or solvents during the process. The reaction occurs between the binary oxide In2O3 and the highly reactive Li3N as the nitrogen source, in the powder form. The formation of the hexagonal phase of InN, occurring at 350 °C and P ≥ 3 GPa, was successfully confirmed by powder X-ray diffraction, with the presence of Li2O as a unique byproduct. A simple washing process in weak acidic solution followed by centrifugation allowed us to obtain pure InN polycrystalline powders as a precipitate. With an analogous procedure, it was possible to obtain pure bulk GaN, from Ga2O3 and Li3N at T ≥ 600 °C and P ≥ 2.5 GPa. These results point out, particularly for InN, a clean, and innovative way to produce significant quantities of one of the most promising nitrides in the field of electronics and energy technologies.

Microwave-assisted two-stage hydrothermal liquefaction of Spirulina to produce high-quality bio-oil with low-carbon ketones

Due to the aggravation of environmental pollution and the massive consumption of fossil fuels, exploring renewable resources has become an important research topic. It is one of the research hotpots to convert algae into bio-oil by hydrolysis. This study studies the preparation of bio-oil with high content of low-carbon ketones by typical algae (Spirulina) using microwave-assisted heating through two-stage hydrothermal liquefaction (HTL). The effects of pre-treatment temperature, pre-treatment time, reaction temperature, reaction time, and reaction environment on the content of low-carbon ketones in the hydrolysate were discussed by setting up the orthogonal experiments. The changes of algae caused by pre-treatment were observed by elemental analysis, TEM and SEM. The samples obtained from the experiment were analyzed by gas chromatography/mass spectrometry (GC/MS) to find the best experimental conditions. Through the research in this study, it is found that the pre-treatment temperature of 80 °C is conducive to the formation of the target product (low-carbon ketones). The pre-treatment time of 20 min is more favorable. At the same time, it is found through experiments that the reaction temperature of 180 °C and the reaction time of 30 min are more conducive to the formation of the ketones. In addition, the weak acid solution environment significantly increases the relative content of the ketones. This study provides the basis for algae to prepare high-quality bio-oil and scientific support for the energy utilization of abundant algae resources.

Corrosion behavior of aluminum in a weak acetic acid solution containing halogen ions as simulated cooling water in HVDC transmission

The effects of F−, Cl−, and Br− on aluminum corrosion in weak acetic acid solutions were studied using a combination of electrochemical methods and physical characterizations, and the pitting factors for aluminum were calculated and used as an effective and intuitive parameter for evaluating aluminum corrosion. The results showed that an increase in the NaCl concentration led to more serious aluminum corrosion, and an increase in the Cl− concentration deepened the degree of pitting corrosion. Among the halogen ions, Cl− was more likely to cause aluminum corrosion. The mechanism for pitting corrosion was developed from these conclusions, which provide guidance for addressing aluminum corrosion.

Formation and characterization analysis of a chromium-free conversion coating on Mg alloy prepared in a Mo-Mn-V based weak acid solution

A molybdenum‑manganese‑vanadium conversion coating (MMVCC) was successfully developed on AZ31B Mg alloy by immersion in a weak acid solution. The FT-IR, SEM, XPS, TEM and electrochemical workstation were used to investigate the morphology, composition, formation process and corrosion resistance of the MMVCC. The results showed that the MMVCC was tightly bonded with the substrate in which the interface exhibited few bubbles and its thickness increased from 273 nm to 1068 nm with the increase of the immersion time from 1 to 15 min. The MMVCC was mainly composed of molybdenum oxides, manganese oxides, vanadium oxides, magnesium hydroxides/oxides, and metal complexes (Mo, Mn, V, Mg, etc). The MMVCC showed superior corrosion properties compared with the substrate and presented optimal corrosion resistance when the forming time was 15 min. The formation process of MMVCC was proposed and discussed based on the results of the XPS and TEM. The main salt (NH4)2MoO4 is changed into MoO2 and MoO3. KMnO4 is an strong oxidizing agent and therefore stable MnO2 is present in conversion coating. The used NaVO3 is changed into VO2 and V2O5 in conversion coating through reductive adsorption and oxidation reaction.The tartaric acid is complexed with metal ions in conversion coating.

DYNAMICS OF DECOMPOSITION OF SOLID HOUSEHOLD WASTE IN THE PRESENCE OF SULFURIC ACID

The article is devoted to the development of technology for obtaining organic-mineral fertilizers and chemical meliorants on the basis of solid waste (SW). The presented article mainly describes the physico-chemical basis of decomposition of solid waste with solutions of different percentages of sulfuric acid, which is the first stage of the study. The purpose of the research is to study the physico-chemical basis of decomposition of solid waste depending on the concentration of sulfuric acid solution, its initial temperature, time and intensity of mixing during the development of technology for obtaining organic-mineral fertilizers and ameliorative substances. During the study, the concentration of sulfuric acid solution from 5% to 70, decomposition dynamics of samples within 36-80 minutes, It was studied under mixing conditions at an intensity of 40 per/min to 180 per/min. It was established that each factor has a great influence on the percentage of decomposition of solid household waste, therefore, the optimal parameters for each factor were determined and clarified as a result of experimental experiments. As a result of the conducted research, it was determined that solid waste from the point of view of the richness of macro-and microelements contained in it is a fully usable raw material for fertilizer production, it has been observed that the extraction of food-repellent elements from the composition of solid household waste with 10-20% sulfuric acid solution is appropriate and in this case, along with the decomposition, the process of neutralization of microorganisms in it takes place. 40-600C optimum temperature of technological process for transition of moisture-repellent elements into solution, it has been proved that the concentration of acid solution is between 10-20% and the mixing intensity is 60-140 per/min., in the end, it is recommended to enrich the composition of the obtained fertilizer with nutritive substances after the completion of the technological process in order to improve the quality of the composition of the obtained liquid fertilizer. As a result of the conducted studies, it was found that during the decomposition of solid waste in the presence of weak acid solutions, about 80-85% of the nutrient elements contained in it can be extracted and used in fertilizer production. Keywords: fertilizer, solid waste, sulfuric acid, ameliorant, salinity, salinization.

Synthesis of freestanding perovskite oxide thin films by using brownmillerite SrCoO2.5 as a sacrificial layer

Freestanding perovskite thin films display many unprecedented properties and exhibit the potential to be easily integrated on other non-oxide substrates or layers. In this work, we demonstrated a pathway to synthesis freestanding perovskite oxide thin films by using brownmillerite SrCoO2.5 as a sacrificial layer. Four representative freestanding perovskite oxide films, e.g., ferromagnetic SrRuO3, La0.7Sr0.3MnO3, dielectric SrTiO3, and ferroelectric Pb(Zr0.2Ti0.8)O3, were produced by etching SrCoO2.5 in Fe(NO3)3 weak acidic solution at room temperature. A 80 nm SrRuO3, which served as an H+ conduction channel, was deposited as a bottom layer of SrCoO2.5 to trigger a quick dissolution for the exfoliation of SrTiO3 and Pb(Zr0.2Ti0.8)O3 poor H+ conductor. Their crystal structure and physical properties were well retained in transferred films. Our work demonstrated the wide applicability of SrCoO2.5 as a sacrificial layer on the synthesis of freestanding perovskite oxide thin films.

Super absorbent glutaric anhydride-modified agar: Structure, properties, and application in biomaterial delivery

Agar was modified with glutaric anhydride (GA) in this study to expand its application in food and medicine. Glutaric anhydride-modified agar (GAR) can maintain high gel strength (1247.4 g/cm2) and improved transparency (82.7 %). The esterified agar formed by GA further formed a cross-linking molecule structure by increasing the reaction temperature. Notably, excellent freeze-thaw stability (24.1 %) and swelling property (3116.6 %) of GAR indicated that the carboxyl-terminal of modified agar improves its affinity with water. Therefore, satisfactory water permeability and expansive stone enable agar films to achieve high water absorption. Furthermore, GAR films exhibit a specific absorption capacity of tetracycline hydrochloride in weak acid solution, thereby suggesting its potential application as a sustainable drug delivery carrier. Finally, the structure of the modified agar was analyzed to explain the mechanism of binding water. Cryo-scanning electron microscopy (SEM) depicted the porous structure of the agar gel responsible for swelling, drug loading, and release. Low-field NMR results showed that GA improves agar gel's binding and free water content. According to our research results, these GAR hydrogel membranes with excellent properties have the potential to be used as effective drug delivery materials.

Deterioration mechanism of hydrothermal aging on the properties of carbon fiber/epoxy composites in various media

This study examined the hydrothermal aging mechanism of carbon fiber reinforced epoxy resin (CF/EP) composites in acidic, alkaline, salt solution, and deionized water (marked as Ac-CF/EP, Al-CF/EP, Sa-CF/EP, and De-CF/EP). The water absorption of carbon fiber reinforced epoxy resin composites followed a two-step process for all four aging mediums, including an initial Fickian diffusion and a subsequent long-term deterioration response. The carbon fiber reinforced epoxy resin composites were degraded more easily in a weak acidic solution due to the degradation of secondary amines and ether bond in an EP molecular chain, which was even degraded into methyl, ethyl, isopropyl, and bisphenol-A monomers. Long-term hydrothermal aging led to significant degradation of the CF/EP composites in all four mediums, the shear strength of the aged composites from small to large was Ac-CF/EP < Al-CF/EP < De-CF/EP < Sa-CF/EP < raw carbon fiber reinforced epoxy resin, which reduced the bending strength by 38.1%, 31.0%, 20.9%, and 11.5%, respectively, compared to the raw carbon fiber reinforced epoxy resin composites. The degradation of the EP matrix and irreversible interface damage caused by hydrothermal aging were considered the main reasons for the degraded mechanical properties of the carbon fiber reinforced epoxy resin composites. It is strongly recommended to apply a protective film on the surface of carbon fiber reinforced epoxy resin composites to reduce the possibility of interaction with humid air.

Behaviour of organic adsorbable corrosion inhibitors containing N, S, and O functional groups on aluminium in weak acetic acid solutions as simulated HVDC cooling water

Functional groups of organic inhibitors containing N, O, S with lone-pair electrons chemically bond with aluminum to inhibit corrosion.