Sulfuric Acid Medium Research Articles

A novel corrosion inhibitor for copper in sulfuric acid media: Complexation of iodide ions with Benincasa Hispida leaf extract

In the context of green and low-carbon development, the rapid development of industry brings the problem of metal corrosion costs increase, metal corrosion protection methods are of great concern. Extracts from Benincasa hispida leaves (BHLE), which were obtained through pressurised liquid extraction, were employed as a inhibitor for copper corrosion in 0.5 M H2SO4. Their composition and anti-corrosion properties were subsequently analyzed and evaluated. The electrochemical analysis results indicated that BHLE functions as a cathodic-type corrosion inhibitor. The anti-corrosion performance intensifies with the increase in concentration but diminishes gradually as the temperature rises, when the concentration of BHLE is 400 mg/L, the corrosion inhibition efficiency can reach 91.82 %, when the concentration of added potassium iodide reaches 16 mg/L the slow-release efficiency of the compounded corrosion inhibitor reaches 96.92 %. The addition of I− strengthens the inhibition efficiency through the adsorption form dominated by competitive adsorption. The adsorption of BHLE onto the surface of copper follows the Langmuir monolayer adsorption model.

Corrosion Inhibition Performances of Amino Acids Corrosion Inhibitors on Carbon Steel in Sulphuric Acid Medium

Abstract The amino acids have great potential in inhibiting metal corrosion. The corrosion inhibition performances of amino acids corrosion inhibitors on A3 carbon steel in sulphuric acid medium were investigated by weight loss method. The corrosion inhibition performances of the alanine, glycine, aspartate, arginine and methionine increase gradually with the dosage of amino acid corrosion inhibitor increase gradually. The five composite corrosion inhibitors were prepared by compound of the five amino acid and potassium iodide respectively to improve the corrosion inhibition performances of amino acids. The corrosion inhibition rate of the five composite corrosion inhibitors is about 20% higher than the amino acid corrosion inhibitors respectively. The amino acid and potassium iodide composite corrosion inhibitors have good protective effects on A3 carbon steel at 30-45°C. The amino acid and potassium iodide composite corrosion inhibitors used for sulfuric acid medium have good protective effects on A3 carbon steel.

A Combined Physical-Mechanical and Hydrometallurgical Approach for Recovering Valuable Metals from Spent Lithium-ion Batteries

In this work, the chemical composition of electrode materials from two samples of lithium-ion batteries (LiB) is comprehensively investigated. The material balance of the physical and mechanical processing of the LiBs mixture is determined. The developed dry process scheme made it possible to extract the following components (wt.%): 15.6 plastic (ABS), 1.89 electronic materials (PP), 59.1 black mass (three types), 6.43 plastic (PVC), 2.97 Al, 6.31 Cu and 7.1 magnetic fraction (Fe). The thermodynamics of reductive leaching of LiCoO<sub>2</sub> in the H<sub>2</sub>SO<sub>4</sub>-HCOOH system was studied. It was calculated that the Gibbs energy of the leaching reaction at 363 K is -327.4 kJ/mol, the equilibrium constant is 2.02×10<sup>44</sup>. All these factors showed the potential of using formic acid as a reducing agent instead of the commonly used hydrogen peroxide solution. It is known to be unstable, since when the solution is heated from 20 to 50<sup>0</sup> C, the decomposition of H<sub>2</sub>O<sub>2</sub> increases 20 times, and the presence of copper sulfate, which usually accompanies the decomposition of the black mass in a sulfuric acid medium, leads to the destruction of 76% of hydrogen peroxide. Therefore, from a practical point of view, it was of interest to study the kinetics of cobalt dissolution from the cathode material in the H<sub>2</sub>SO<sub>4</sub>-HCOOH system. It was shown that the Crank-Ginstling-Braunstein equation agrees satisfactorily with the experimental data, which indicates intra-diffusion limitation of dissolution. The activation energy was determined. The optimal composition and conditions of the leaching solution for dissolving cobalt, lithium and associated transition metals from the black mass were determined. The thermodynamics and kinetics of dissolution of Ag, Au and Pd from electrode materials in a bromide-bromine solution were also studied.

Dissolution process and mechanism of montmorillonite in oxalic acid and sulfuric acid media at various pH levels

The dissolution of silicate minerals plays a crucial role in many natural geological processes. In order to better comprehend the reaction mechanisms and dissolution characteristics of montmorillonite in different acidic systems, the effects of interfacial reactions of montmorillonite with oxalic and sulfuric acid solutions at various pH levels on the ionic dissolution, crystal structure, and micro-morphology were studied, and the morphology of aluminum and saturation index of secondary mineral were simulated. It was shown that the dissolution amounts of Mg2+, Al3+ and Si4+ in montmorillonite structure decreased with the increase of pH value, which reflected the dependence of montmorillonite dissolution on the pH value of solution. The dissolution percentages of Mg2+, Al3+ and Si4+ after the reaction of montmorillonite with oxalic acid solution were greater than those in sulfuric acid solution, and the highest dissolution rate of Al3+, indicated that both ligands and protons attacked the surface sites of montmorillonite and accelerated the dissolution of ions. Moreover, oxalate ligands exerted specific binding effects on Al3+ ions. While reacting with oxalate and sulfate, the tetrahedral, octahedral and interlayer cations of montmorillonite exhibited the non-stoichiometric and inconsistent dissolution. The oxalate ligands have a strong complexation effect on Al3+, so that Al3+ in oxalate solution exists in the form of aluminum oxalate complex, which reduces the effective concentration of Al3+ in solution and promotes the dissolution of Al3+ in montmorillonite structure. The Mg2+ ions settled at octahedral substitution sites possessed weak stability, while those from the interlayer featured strong interlayer interchangeability, demonstrating the dissolution percentage up to 10.85 % and 8.62 % even in oxalic and sulfuric acid solutions at pH of 6.5. All secondary mineral phases in the solution were undersaturated, making the montmorillonite dissolution difficult to balance. Montmorillonite has a high cation exchange capacity, which makes it have a strong buffer capacity to exogenous acids. This study helps to explain the dissolution process of montmorillonite in inorganic and organic acid solutions at different pH value.

Sodium salt of dodecyl benzene sulphonic acid as an effective corrosion inhibition for different heat-treated steel in sulphuric acid medium

Abstract The purpose of this work is to use electrochemical and gravimetric techniques to investigate the inhibition of DBSS on the corrosion of heat-treated dual-phase AISI 1040 steel in a 0.5 M sulphuric acid solution at 35 °C. The corrosion studies are performed by potentiodynamic polarization study (PDP), electrochemical impedance study (EIS), and gravimetric method. To confirm the inhibition surface characterization like x-ray diffraction technique (XRD) analysis, scanning electron microscopy (SEM), and EDS analysis are performed. Depending on the phase change of metals due to heat treatment, the corrosion inhibition of the heat-treated metal increased when it was exposed to 0.5 M H2SO4 at 35 °C in the presence of dodecyl benzene sulphonic acid sodium salt (DBSS) inhibitor. The highest inhibition efficiency of 63%, 82%, 87%, 43%, and 63% was obtained for AISI 1040 steel at heat treatment conditions of Normalized, Quenched at 700 °C, Quenched at 750 °C, Quenched at 790 °C and Quenched at 900 °C respectively. In the gravimetric and electrochemical study, the IE increases with the increase with the concentration of DBSS unto 75% from gravimetric analysis and 87% from PDP analysis for Quenched at 750 °C and 790 °C respectively. The metal protection is achieved by heat treatment process as well as by using DBSS as inhibitor. Corrosion inhibition on the metal’s surface was confirmed by SEM and XRD. In addition, the adsorption of DBSS on the anodic and cathodic sites of the metal surface was well explained.

Indole derivatives efficacy and kinetics for inhibiting carbon steel corrosion in sulfuric acid media

The global prevalence of metal corrosion is a significant challenge due to its detrimental effect. Environmentally friendly and non-hazardous alternatives for harmful and poisonous synthetic corrosion inhibitors are urgently necessary due to increasing environmental concerns and regulations prohibiting their application. In this study, indole molecules were employed as carbon steel corrosion inhibitors in acidic conditions. Gravimetrical and scanning electronic microscope (SEM) analysis was used in a preliminary investigation of indole as an organic inhibitor. The results revealed that adding indole to carbon steel before exposing it to sulfuric acid slowed and induced resistance to corrosion. The indole affixed themselves to the steel carbon surfaces, producing a barrier/protection for carbon steel. The efficacy of the indole in preventing corrosion was determined through the weight loss method. Temperature and inhibitory concentration effects on inhibition effectiveness under varying parameters were also reported. The temperatures employed were between 298 K and 328 K, while the inhibitor concentrations ranged from 1.2 × 10−3 M to 7.6 × 10−3 M, and both parameters significantly influenced corrosion inhibition effectiveness. The inhibitory mixture attained optimum efficacy in inhibiting corrosion, at 81 %, when the lowest and highest respective temperature and concentration were applied. The kinetic analysis was conducted under a range of temperatures to determine the reaction mechanisms of the inhibitor. The thermal adsorption isotherm of the inhibitor indicated that the surface adhered to Langmuir's adsorption isotherm. Additionally, investigations on corrosion and inhibition using the electrochemical impedance spectroscopy method (EIS) were conducted. This study can provide in-depth knowledge for advancing inhibitory science and engineering to enhance corrosion resistance in acidic media.

Synthesis, spectroscopic characterization of a new schiff base molecule, investigation as an efficient corrosion inhibitor for copper in sulfuric acid medium: combination of experimental and theoretical researches

A new Schiff base inhibitor known as “N, N’ carbonyl- Bis (para-hydroxy benzaldehyde imine)” has been synthesized and characterized by FTIR, NMR, and UV-Visible spectroscopy, the molecule was then assessed for its ability to prevent copper from corroding in a solution of 0.5 M H2SO4 using potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy SEM combined with energy dispersion spectroscopy EDX, and atomic force microscopy AFM. The tested inhibitor exhibits good copper corrosion inhibition performance in a 0.5 M H2SO4 solution. As inhibitor concentration rises, inhibition performance also rises, reaching a maximum inhibitory efficacy of around 84.76 ± 0.69% at 5.10−4 M. The inhibitor was adsorbable to the metal surface and followed the Langmuir isotherm. It has been done such that the addition of KI increased the inhibitory effectiveness, the mixed additives worked together. There is good agreement between the conclusions drawn from theoretical calculations using DFT and MD simulation and actual observations.

Bidentate pyridine-pyrazole ligand-induced synergistic and antagonistic effects for selective separation of nickel from sulfuric acid medium

Short-process hydrometallurgy is promising for non-traditional resource utilization due to low cost and less consumption, but it presents a great challenge to metal separation of complex leaching solutions. Herein, a bidentate pyridine-pyrazole ligand (BPP) was synthesized to realize the direct extraction of nickel from sulfuric acid leachate of laterite ore. The separation behaviors of nickel over other impurities (Co, Mn, Mg, Al, Ca, Fe, and Zn) were evaluated for the mixtures of BPP and dinonyl naphthalenesulfonic acid (DNNS). This binary system exhibits the synergistic effect on nickel and antagonistic effect on impurities, which improves the selective separation of nickel. The molar ratio of BPP/DNNS, solution pH, extractant concentration, and nickel concentration on metal extraction were investigated. The extraction efficiency of nickel reaches 95.9 % at pH = 2.5, and the separation coefficients of nickel over aluminum, manganese, and iron is 86.2, 95.4, and 69.4 at the optimal DNNS/BPP molar ratio of 1:1, respectively. Furthermore, the component interaction and coordination structure were disclosed through NMR, ATR-IR, XAS, and UV–vis spectroscopies. The mechanism analysis indicated that the exclusion of coordinated water molecules with BPP contributes to the synergistic extraction of nickel, and the intermolecular interaction between DNNS and BPP inhibits the extraction of impurities. Therefore, the pyridine-pyrazole ligand-induced synergistic and antagonistic effects will be helpful to the short process utilization of complex nickel-bearing resources.

Optimisation of the corrosion inhibition performance of isatin 4-ethyl-3-thiosemicarbazone for mild steel in sulfuric acid medium using response surface methodology

Optimisation of the corrosion inhibition performance of isatin 4-ethyl-3-thiosemicarbazone for mild steel in sulfuric acid medium using response surface methodology

Remarkable structural effects on the extraction behavior of uranium from sulfuric acid medium using di-alkylhydrogen phosphonates: Insights from EXAFS and DFT computations

The structural effects of the carbon chain on the extraction of uranium have been examined by dialkylhydrogen phosphonates (DalHPs). The extraction of uranium by 0.55 M solutions of DalHPs in n-dodecane (n-DD) was investigated as a function of aqueous phase sulfuric and phosphoric acid concentration (0.1–6 M), and the obtained results were compared with 0.55 M solution of tri-n-butyl phosphate (TBP) in n-DD system under similar experimental conditions. The batch distribution data for the extraction of uranium from sulfuric acid and phosphoric acid medium indicated that DalHPs showed dual extraction behavior, i.e., cation exchange at lower acidities and solvation at higher acidities. The extraction of uranium from the sulfuric acid medium was found to be higher than that from the phosphoric acid medium. The extracted U-DalHPs complexes were characterized by extended X-ray absorption fine structure (EXAFS) and the local atomic structure was discerned. The coordination number of uranium was derived from the EXAFS fitting data for various sulfuric acid concentrations. Density functional theory (DFT) computations were performed to understand the electronic structure and binding affinity of U-DalHPs. An acid-dependent extraction mechanism was derived computationally to understand the complexation of U-DalHPs. The trends observed in the distribution ratios of uranium, and the coordination number deduced from EXAFS fitting was found to be in good agreement with the DFT computations. These investigations have opened up new avenues for use of DalHPs for the extraction/recovery of heavy metal ions from sulfuric acid medium.

Carbazole derivatives as antioxidant and anticorrosion materials

In this study, a series of new carbazole derivatives were studied using several reactions, including the Vilsmeier–Haack reaction. A cyclization reaction within bromoacetic acid was reported to synthesize thiazolidinone compounds, followed by the Mannich reaction by reacting the prepared compound with formaldehyde and secondary amines, that is, diphenylamine, morpholine, and phthalimide. All synthesized compounds were characterized by infrared spectroscopy, liquid chromatography–mass spectrometry, and 1H and 13C nuclear magnetic resonance spectroscopy. The antioxidant activities of all prepared compounds were studied using the free-radical scavenging method using 2,2-diphenyl-1-picrylhydrazyl, demonstrating their moderate activity compared with ascorbic acid as the standard substance. The effectiveness of the prepared compounds as corrosion inhibitors was studied in an acidic medium of sulfuric acid (0.25 mol/L) using the electrochemical method. Acceptable corrosion-inhibition efficiency was achieved, with the highest inhibition rate of 55.21 % for compound VII.

The inhibitory properties of the boiling extracts from Malus sylvestris and Syringa vulgaris flowers on the corrosion of stainless steel in sulphuric acid medium

The inhibitory properties of the boiling extracts from Malus sylvestris and Syringa vulgaris flowers on the corrosion of stainless steel in sulphuric acid medium

A new extraction mechanism in sulfuric acid media for the recovery of aluminum

The separation of aluminum and manganese from mineral leach solutions has been a challenge at present and has attracted great interest. In this paper, the effects of different extractants on aluminum recovery as well as the effects of the concentration of the most suitable extractant, extraction temperature, initial pH and organic phase/aqueous phase ratio on the recovery of aluminum were investigated. The results showed that for chromite recovery solution(CRS) with an initial aluminum concentration of 0.1221 g/L, S-NA at 0.25 mol/L exhibited good selectivity and extraction efficiency for aluminum, and was able to separate aluminum from other elements and recover it easily for secondary use without scrubbing. The extraction mechanism of aluminum in sulfuric acid medium was investigated through various analyses including the combination of energy and bond length calculations, electrostatic potential (ESP) theory calculations, IGMH analysis, process chemistry analysis, and thermodynamic equilibrium species calculations. These analyses showed that Al(III) was distributed in the recycling solution in the form of AlSO4+ and had strong interactions with naphthenate ions, and that the combination of AlSO4+ with the naphthenate ions(R−)’s formed the stable complex molecule AlSO4R. The study provides a feasible path for the recovery of aluminum in CRS and is of guiding significance for the theoretical study of aluminum in sulfuric acid media.

UV radiation effect on the corrosion inhibition potential of Helichrysum kraussii plant extract on mild steel metal in sulphuric acid medium

The comparison of the effect of UV-radiated and non-radiated Helichrysum kraussii (H. kraussii) extracts was studied for mild steel corrosion in 1.0 M H2SO4 at 30–60 °C using Liquid chromatography-mass spectrometry (LCMS), gravimetric weight loss analysis, electrochemical analysis and Fourier Transform Infrared spectroscopy (FTIR). The LCMS confirmed the trans-to-cis shift geometrical isomerisation for H. kraussii due to UV radiation. From the gravimetric analysis data, the corrosion rate was calculated and found to be decreasing with an increase in the concentration of the inhibitor extracts, with the highest concentration at 30 °C having a corrosion rate of 3.920x10-4 and 1.700x10-4 g.cm2.h−1 for UV-radiated. Non-radiated H. kraussii extract gave the highest inhibition efficiency of 96.663 % compared to 92.503 % of the UV-radiated H. kraussii extract. The semi-circles diameter of the Nyquist plot from the electrochemical impedance spectroscopy (EIS) was found to increase with an increase in the inhibitor concentration, suggesting the increase in inhibition with an increase in the concentration of the two extracts. Functional groups such as C = C, O-H, and N-H, known to be functional groups of the most effective corrosion inhibitors, were observed for both extracts from FTIR. Based on the results obtained, it was found that the UV-radiated H. kraussii extract was more effective in inhibiting the corrosion of mild steel in sulphuric acid than the non-radiated H. kraussii extract. This suggests that UV radiation decreases the efficiency of the H. kraussii extract as a corrosion inhibitor for mild steel in H2SO4. Therefore, it is recommended that the H. kraussii extract be used only as a corrosion inhibitor for mild steel in 1.0 M H2SO4 in its original state without being exposed to UV radiation.

NIR-responsive carbon dots as an oxidative-stress amplifier and hyperthermia-induced superior photothermal in-vitro anticancer activity

A facile wet chemistry-based strategy was developed to synthesize orange emissive Carbon dots (O-CDs) based on dehydration-induced ring-fusion of the precursor (1,3-dihydroxynaphthalene) in a dehydrating sulfuric acid medium. The O-CDs revealed significant Near-infrared (808 nm) light harvesting potential with outstanding photothermal conversion efficiency (∼58%) and hence exhibited excellent NIR-light stimulated photothermal anticancer performance. Furthermore, these fluorescent O-CD nanoprobes displayed excitation-dependent polychromatic emissions in the range of 540–640 nm, with the dual emission maxima at 540 and 580 nm, corresponding to yellow and orange emission at the excitation of 490 nm. Various mitochondrial, as well as cytoplasmic apoptosis-related proteins and genes were upregulated during photothermal treatment, which suggests that hyperthermia and oxidative stress have a major impact on cell death. The anticancer activity of O-CDs is likely due to the elevated reactive oxygen species (ROS) amplification in cooperation with the hyperthermia effect. This study offers a potential alternative to bio-nanomedicine for cancer treatment by carbon-based photothermal therapy.

Enhanced activity and durability of Pt nanoclusters catalyst by using nitrogen-doped carbon layer coated carbon nanotubes as anchors and nanowires for ORR

Platinum-based catalysts remain the top choice for oxygen reduction reaction (ORR) in fuel cells. However, their activity and durability in the acidic medium are still under improvement. In this work, the Pt nanoclusters anchored the nitrogen-doped carbon nanotubes (Pt-NCNTs) have been synthesized by using a series process of pyrrole coating on the CNTs and subsequent pyrolysis to the chemical immersion reduction of Pt ions. The inner CNTs of Pt-NCNTs function as the nanowires offering a high-speed pathway for electron transport, and the Pt nanoclusters increases the active sites. The theoretical calculation demonstrates that the local structural defects and the uneven charge distribution induced by nitrogen-containing functional groups and porous structure are favorable to capture Pt ions for the nucleation of Pt nanoclusters. Compared with the commercial 40 wt% Pt/C (0.94 and 0.80 V), the Pt-NCNTs-1000 with Pt loading amount of 33.0 wt% owns the more positive onset potential and half-wave potential of 0.97 and 0.81 V in the sulfuric acid medium. Meanwhile, the strong attachment of Pt nanoclusters on the nitrogen-doped porous carbon layer results in a stable interface to effectively prevent the metallic species from migration and agglomeration during the electrode reactions. Therefore, the ORR current of Pt-NCNTs-1000 retained 84.3% of the initial value after 50000 s operation superior to the commercial Pt/C (64.6%).

Encapsulation of Acacia bark extract (Acacia mangium) by maltodextrin-carrageenan for corrosion inhibition steel in sulfuric acid medium

Encapsulation of Acacia bark extract (Acacia mangium) by maltodextrin-carrageenan for corrosion inhibition steel in sulfuric acid medium

Justicia brandegeeana as a green corrosion inhibitor for carbon steel in sulfuric acid

ABSTRACT The anti-corrosive effect of the extract in ethanol of Justicia brandegeeana (Acanthaceae) against carbon steel AISI 1020 in sulfuric acid medium 1 mol L−1 was investigated. In addition to the effect of seasonality, several techniques were used to investigate the anti-corrosive activity, such as electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), linear polarization resistance (LPR), and weight loss. The chelating effect was analyzed by UV-Vis spectrophotometry and the surface was analyzed by scanning electron microscopy (SEM). The results showed that the inhibition efficiency is dependent on the concentration of the extract, reaching its maximum at 1500 ppm and despite having good thermal stability (82.41% inhibition at 70°C), it decreases with increasing temperature, indicating a physisorption behavior. The extract obeyed the Langmuir isotherm and the Tafel curves characterized it as a mixed inhibitor, with a tendency to cathodic region. It also presented a 52% chelating effect against Fe+2 ions, and the SEM analysis indicated a protection with the presence of plant extract, thus minimizing surface roughness. These results indicated the J. brangeeana ethanol extract as a green anti-corrosive agent.

Insights into the Corrosion Inhibition Mechanism of Canavalia gladiata Leaf Extract for Copper in Sulfuric Acid Medium.

Canavalia gladiata leaf extract (CGLE) is extracted from crop waste employing a water decoction method. By employing electrochemical techniques, morphology analysis, quantum chemical calculations, and other methods, we extensively investigated the anticorrosion efficacy of CGLE on copper within a H2SO4 solution. The outcomes reveal that at 298 K, a CGLE concentration of 800 mg/L attains a remarkable inhibition efficiency (IE) of 96.8%. Additionally, we examined the impact of CGLE on the corrosion resistance of copper at varying temperatures. Even with rising temperatures, CGLE manages to sustain an IE of over 95%. This indicates that CGLE is mainly chemisorption based on the copper, leading to a strong adsorption. The surface test results show a noteworthy decrease in the extent of copper surface corrosion upon the introduction of CGLE. The study of the adsorption model demonstrates the alignment of CGLE adsorption onto the copper with the Langmuir adsorption.

Synthesis of Green Inhibitor for Mild Steel Corrosion in a Sulphuric Acid Medium

Synthesis of Green Inhibitor for Mild Steel Corrosion in a Sulphuric Acid Medium