Sulfuric Acid Medium Research Articles

NEW CORROSION INHIBITORS BASED ON AMINES AND AMIDES

In this work, new inhibitors of metal corrosion in sulfuric acid media are investigated depending on the duration of the process, inhibitor concentration and temperature. The main parameters of the synthesis of new corrosion inhibitors for metals of grade St.3 and St.12 with the use of amine and amide-containing organic substances have been determined, and methods for preparing these inhibitors have been described. The physicochemical properties of amine and amide containing organic inhibitors of corrosion and salt deposition in acidic process media have been studied.

Pd (II) complexes bearing “SNS” pincer‐type thioether ligands: Application as catalysts in the synthesis of vitamin K3

The novel four SNS pincer‐type thioether containing Pd (II) complexes were synthesized and characterized by using FT‐IR, UV‐Vis, mass, elemental analysis techniques. The complexes were used as catalysts in the synthesis of vitamin K3 (2‐methyl‐1,4‐naphthoquinone) from 2‐methyl naphthalene. Hydrogen peroxide was used as green oxidant in acetic acid and sulfuric acid medium. L2‐Pd (II) and L3‐Pd (II) complexes showed the best catalytic activity with 62.63% and 61.05% selectivities in the conversions of 82.61% and 87.84%, respectively. Moreover, in silico studies on Pd (II) complexes have shown that L2‐Pd (II) and L3‐Pd (II) complexes have low band gaps between LUMO and HOMO energy levels and their electrostatic energy values are higher than other complex structures. This reveals that they have better chemical activity than other complexes and also supports the experimental studies carried out in this research. The conversions and the selectivities of these complexes are one of the best compared to the literature. Peroxyacetic acid with sulfuric acid is a very important oxidant in the oxidation of 2‐methyl naphthalene to 2‐methyl‐1,4‐naphthoquinone.

An investigation on corrosion inhibition efficacy of benzodiazepines on mild steel in acid medium

Corrosion inhibition efficacy of the synthesized benzodiazepines namely Dimethyl-[4-(4-phenyl-2,3-dihydro-1H-benzo[b][1,4]diazepin-2-yl)-phenyl]-amine (DPBD) and Dimethyl-[4-(4-methyl-2,3-dihydro-1H-benzo[b][1,4]diazepin-2-yl)-phenyl]-amine (DMBD) on commercially available mild steel in sulphuric acid medium was investigated by Electrochemical and Weight loss studies. From the results, it has been affirmed that DPBD is effective in combating corrosion, exhibiting maximum inhibition efficacy of 86% at 100 ppm at 303 K. The adsorption efficacy of DPBD and DMBD over the metallic surface was identified to comply with the Langmuir adsorption isotherm model. The development of a protective layer on the surface of the mild steel was confirmed by the Scanning Electron Microscopic studies (SEM).

Electrochemical studies and molecular simulations on the use of molybdic acid for stabilization of AISI 304 stainless steel passive film in sulfuric acid medium

In this work, the corrosion of AISI 304 stainless steel (SS) in the absence and presence of different concentrations of molybdic acid was investigated using potentiodynamic polarization, open circuit potential (OCP) measurements, electrochemical impedance spectroscopy (EIS), Mott-Schottky analysis (MS) and theoretical simulations including molecular dynamics (MD), Monte Carlo (MC), and density functional theory (DFT). Although it is obvious that the use of molybdate ions can improve the anti-corrosion properties of austenitic SS, there are fewer comprehensive reports which has been devoted to “investigation of electrochemical properties of passive film” and/or “theoretical studies using molecular-scale simulations”. Therefore, the present study focused on examining these two issues. The results of potentiodynamic polarization showed that molybdic acid not only can reduce the corrosion rate but also decrease the critical current density (icrit) for passive film formation. MS analysis revealed the donor density in the passive film was increased up to 6.6 × 1020 cm−3 by increasing the molybdic acid concentration to 0.02 mM. The computational studies associated with MD and MC simulations showed that the adsorption energy of molybdic acid, as an inhibitor on steel surface, is −35.4 and −98.3 kcal mol−1, respectively. Moreover, the HOMO and LUMO energies and the energy difference between them were calculated by DFT simulation.

Dysphania ambrosioides Essential Oil: An Eco-friendly Inhibitor for Mild Steel Corrosion in Hydrochloric and Sulfuric Acid Medium

Dysphania ambrosioides Essential Oil: An Eco-friendly Inhibitor for Mild Steel Corrosion in Hydrochloric and Sulfuric Acid Medium

Carbon nanotubes functionalized with newly synthesized benzimidazole derivative for corrosion inhibition on the nickel alloy surface in a sulfuric acidic medium

3-methoxy-4-(1-phenyl-1H-benzimidazol-2-yl)phenol (MPBP) was synthesized by adding N-phenyl-o-phenylenediamine, 4-hydroxy-2-methoxybenzaldehyde and ammonium acetate in the presence of ethanol and nano silica at 80 °C. Newly synthesized benzimidazole was characterized by proton NMR, carbon NMR, LC-Mass spectral studies and elemental analysis. Nickel alloys play a major role in fields like automobiles and ship building owing to their stability in Acid, Base and Saline environments. CNT’s are having high stability against corrosion. So it has been planned to prepare 3-methoxy-4-(1-phenyl-1H-benzimidazol-2-yl)phenol-functionalized carbon nanotubes for corrosion-inhibiting barrier layer on nickel alloy surfaces. The evidence of corrosion inhibition efficiency of 3-methoxy-4-(1-phenyl-1H-benzimidazol-2-yl)phenol-functionalized carbon nanotubes coated on nickel alloys was confirmed by FTIR spectral studies (essence of spectra need to include). The nature of inhibition of corrosion was determined using electrochemical methods. 3-methoxy-4-(1-phenyl-1H-benzimidazol-2-yl) phenol functionalized CNTs displayed excellent corrosion inhibition on the nickel alloy surface.

Separation of Uranium(VI) and Vanadium(V) from Sulfuric Acid Media by Amine Based Extractants through Liquid-liquid Extraction Technique#

Separation of Uranium(VI) and Vanadium(V) from Sulfuric Acid Media by Amine Based Extractants through Liquid-liquid Extraction Technique#

Kinetic Study of the Ultrasound Effect on Acid Brown 83 Dye Degradation by Hydrogen Peroxide Oxidation Processes

The effect of ultrasound on the degradation of the dye Acid Brown 83 by seven different degradation methods (blank test using only ultrasound, hydrogen peroxide in a neutral medium, hydrogen peroxide in a sulfuric acid medium and hydrogen peroxide in a sulfuric acid medium in the presence of Fe(II), both without and with ultrasonic irradiation) is studied in this paper. The effectiveness of these methods is compared by analyzing the degradation percentages of the dye and its initial degradation rate. The application of ultrasound leads to a significant increase in the efficiency of any of the degradation method studied. Kinetic study of Acid Brown 83 degradation by the above-mentioned methods is carried out by using four kinetic models (first order, second order, Behnajady and pseudo-first order). The pseudo-first order model is the one that best fits the experimental data in all the used degradation methods. Although when the degradation is performed in the presence of Fe(II), the Behnajady model presents correlation coefficients slightly higher than those of the pseudo-first order, the maximum experimental conversions obtained fit much better in all cases to the pseudo first order model.

A new pyridazine derivative synthesized as an efficient corrosion inhibitor for copper in sulfuric acid medium: Experimental and theoretical calculation studies

A new type of pyridazine-based derivative namely, 2-[(6-ethoxy-3-pyridazinyl) thiyl]-N, N-diethylacetamide (EPD), was synthesized and developed as a corrosion inhibitor of copper in 0.5 M sulfuric acid. Electrochemical and surface characterization were combined to investigate the inhibition performance of EPD. The results show that copper corrosion in sulfuric solution is efficiently inhibited by EPD at different temperatures. The maximun inhibition efficiency (η) obtained by electrochemical impedance spectroscopy (EIS) are 94.1% at 298 K, 93.2% at 308 K, 91.3% at 318 K for 4 mM EPD. The favorable performance is ascribed to the formation of EPD adsorption films on the surface of the copper, which follows the Langmuir adsorption isotherm. Besides, theoretical calculations further revealed the interaction between EPD and copper surface and the mechanism of inhibition of EPD.

Nanocellulose Preparation from Cassava Bagasse via Hydrolysis by Sulfuric Acid and Hydrogen Peroxide Medium

Nanocellulose Preparation from Cassava Bagasse via Hydrolysis by Sulfuric Acid and Hydrogen Peroxide Medium

Pursuing green and efficient process towards recycling of different metals from spent lithium-ion batteries through Ferro-chemistry

Sustainable recycling of different value-added metals from spent lithium-ion batteries (LIBs) can expect significant environmental and economic benefits for the fulfillment of resources utilization. During the separation and recovery of different metals, excessive chemical consumption caused by prolonged processes may eventually spoil the environmentally soundness recycling of spent LIBs. Here, Ferro-chemistry was innovatively proposed towards the recycling of different metals based on transformation of iron morphology from different types of spent LIBs (LiCoO2 and LiFePO4). It can be concluded from the thermodynamic results that redox reaction will take place in dilute sulfuric acid medium without addition of reductant/oxidant, indicating that Fe(II) in LFP can be used as reductant for the direct leaching of LiCoO2. Leaching results indicate that 99.9% Li, Fe, P and 92.4% Co can be dissolved and existed as Fe3+, Li+, PO43− and Co2+ under the optimized conditions, with a decline of over 80% acid consumption. The leaching kinetics of different metals and reaction mechanism suggest that Fe(II) will be promptly liberated to lixivium and then slowly oxidized into Fe(III) with the existence of Co(III), resulting in a synergetic leaching of Co and Fe. Then, Fe(III) can be precipitated as FePO4 at pH of 2.5, which can remove PO43− with the direct generation of LiFePO4 precursors. This above ferro-chemistry strategy can effectively reduce the consumption of chemicals with reduced environmental footprint.

Synthesis and evaluation of poly (Indole/Thiophene) fused ring derivative for C- steel corrosion inhibitor in sulfuric acidic medium

The current study aims to explore the anti-corrosion performance of Poly [2 -amino -4(1 -benzyl -1H -indol - 3 -yl) thiophene - 3 - carbonitrile)] (PABITC) on C-steel in in 0.50 M H2SO4 using weight loss and potentiodynamic polarization measurements (PDP).. PABITC was synthesized with different molecular weights 882, 921, 1388, 15788 g/mol using APS as an oxidizing agent. The chemical structure of the polymer was characterized using H1NMR, DNMR, C13NMR, and FTIR spectroscopy. Polarization results reveal that the synthesized polymer acts as a hybrid-type inhibitor. The adsorption of inhibitory atoms of the polymer on the C- steel surface followed Langmuir isotherm. SEM and EDX assure the development of PABITC adsorbed film on the C- steel surface. Quantum calculations were carried out to elucidate the reactive sites in PABITC. All the results approve that PABITC makes a resistive layer to shrink the corrosion process.

Three piperazine compounds as corrosion inhibitors for copper in 0.5 M sulfuric acid medium

BackgroundSearching for and developing green corrosion-resisting drugs plays an significant role in protecting Cu during its pickling treatment. The toxicities and inhibitive performances are closely correlated with their molecular formulas. MethodsTherefore, Amoxapine, Loxapine and Clozapine, all of which belong to piperazines, were assessed as inhibitive agents to protect Cu from corrosion in 0.5 M H2SO4 via electrochemical measurements, surface morphologies and theoretical calculations. According to the electrochemical results, the anti-corrosion efficiencies of AP, LP and CP reached their maximums at 5 mM, namely 94.0༅, 95.2༅ and 96.6༅, respectively. They were all proved to be cathodic-type corrosion inhibitors. The morphology analysis implied the shaping of protective films on Cu surfaces. Moreover, the absorption of AP, LP and CP on Cu surfaces deferred to the Langmuir isotherm model, confirming the analysis of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS). Theoretical calculations revealed their adsorption models and anti-corrosive mechanisms. Significant FindingsBoth experiment and calculation manifested favourable corrosion-proof properties of the three researched drugs. Further analysis also proved the enhanced inhibitive effect of methyl that connected with benzene ring owing to its conjugative effect. Furthermore, N atom possessed higher electronegativity and accordingly stronger electron-donating ability compared to O atom. The corrosion-resisting efficiency of Clozapine was 96.6%, being higher than that of Loxapine which was 95.2%.

Synthesis and characterization of nanostructured Pb-Co-Sn film for the oxygen evolution reaction in sulfuric acid media

Synthesis and characterization of nanostructured Pb-Co-Sn film for the oxygen evolution reaction in sulfuric acid media

Experimental design modelling for the extraction of vanadium(IV) extraction V(IV)-SO<sub>4</sub> <sup>2-</sup> (H+, Na+)-Cyanex 301-kerosene system

The vanadium(IV) extraction from acidic sulphate medium by Cyanex 301 (bis-(2,4,4-trimethylpentyl) dithiophosphinic acid) dissolved in kerosene is explored from the modelling point of view. The time of equilibration is only 10 min and above pH(eq) = 2, high extraction (>90%) occurs.On keeping organic to aqueous phase ratio of 1, factors affecting the extent of extraction (log D and log CD) are pH(eq), [V(IV)],[SO4 2-], [Cyanex 301]and temperature (T). The high (+) and low (-) levels are considered for the factors. The 25 factorial design is used to find the regression equation for the V(IV) extraction by Cyanex 301. On symbolizing pH(eq), log [V(IV)], , log [SO4 2-], log [Cyanex 301], and 1/T (K-1); where concentration terms are in mol/L, as P , M, S,E, and (1/T), respectively,the regression equation obtained is: log CD = 1.95 - 0.23 M + 1.83 P + 2.07 E + 0.84 S - (888.9/T) - 0.26 PS.The current system shows only the interaction effect among pH(eq) and [SO4 2-]. The equation can well describe the system,and it can be used to optimize factors for satisfactory extraction.
 Bangladesh J. Sci. Ind. Res.56(2), 95-104, 2021

Mixed gel electrolytes: Synthesis, characterization, and gas release on PbSb electrode

Abstract Mixed gel electrolytes were fabricated chemically at a temperature range of 2–5°C using some additives comparing with traditional electrolytes (1.26 g/cm3 H2SO4). The polyacrylamide (PAM) content is kept constant (0.2 wt%), while the propylene glycol (PPG) and nano fumed silica (NFS) contents varied. The material characteristics of samples were assessed by physical appearance observation, electrochemical measurements, and physicochemical methods. The results showed that a hard gel without separation of solutions was found in the case using a PAM/PPG/NFS ternary additive (0.2/0.1/0.6 wt%). The morphological structure (<50 nm) of mixed gel electrolytes was in the range of nanometer. The gas release on the PbSb electrode was strongly inhibited (92.2–93.7% for O2 and ∼55% for H2 at the 120th cycle), which will both contributes to reducing the pressure as well as limiting water loss in the sealed lead acid battery, compared with that in the sulfuric acid medium.

Investigation of Corrosion Performance of Pure Aluminum as Bipolar Plate in PEMFC Environment

Corrosion behavior of pure aluminum in sodium fluoride and sulfuric acid media with different concentrations at 80°C for use as bipolar plate in PEMFC environment was investigated. Open circuit potential, single cell operation, amount of corrosion, and surface roughness of pure aluminum were measured to check the corrosion potential, corrosion resistance, corrosion amount, and surface roughness, respectively. Scanning electron microscopic images and energy-dispersive X-ray spectra were also taken to analyze the surface morphology, and elemental compositions.

Combining experiment and theory researches to insight into anti-corrosion nature of a novel thiazole derivatives

The propensity of acid corrosion for X65 steel substrate leads to application restrictions. In this research, we develop an efficient and new corrosion inhibitor, S-(benzo[d]thiazol-2-yl) (E)-2-(2-aminothiazol-4-yl)-2-(methoxyimino)ethanethioate (BTAE), as a first example of a sulfuric acid medium additive containing both benzothiazole and aminothiazole with multiple anchoring centers, which can inhibit the X65 corrosion in the sulfuric acid medium. The electrochemical experiment test shows that BTAE can effectually control the anodic reaction of X65 steel and belongs to the anodic type corrosion inhibitor. The corrosion inhibition efficiency of BTAE can still be maintained above 97% within a certain temperature range. The surface topography analysis and electrochemical test results are highly consistent. The adsorption of BTAE onto the interface of X65 steel conforms to the Langmuir model. Quantum chemistry and molecular dynamics simulation results have proved that BTAE is an excellent corrosion inhibitor.

Recovery of manganese from a low-grade waste and valorization via the synthesis of a nanostructured magnetic manganese ferrite

This study aims at recovering manganese from a low-grade mining waste and valorizing it through the synthesis of manganese ferrite (MnFe2O4). Full recovery of manganese from the low-grade waste was obtained by heat treatment (700 °C), and leaching optimization of the waste in a reductively promoted sulfuric acid medium. Subsequently, the Fe: Mn molar ratio (2:1) of the leachate was adjusted to prepare the precursors for the MnFe2O4 synthesis through co-precipitation. The optimization of the synthesis parameters including temperature (15–90 °C), aging time (0–120 min), and calcination temperature (800–1200 °C) was investigated. The optimum condition suggested by the response surface method (RSM) led to the synthesis of pure plate-like MnFe2O4. Additionally, nano-sized particles (45 nm) were obtained at the 90 °C synthesis temperature, 120 min aging time, and without any calcination. Both nano-sized and plate-like MnFe2O4 particles with the saturation magnetization of 34.47 and 51.03 emu g−1 presented superior magnetic properties.

Use of Phytic Acid for the Removal of Iron in Hot Acidic Leachate from Zinc Hydrometallurgy

In zinc hydrometallurgy, hot-acidic leaching of calcines leads to Fe/Zn solutions in sulfuric acid medium. Three distinct processes have been previously developed to remove iron: jarosite, goethite and hematite. Each process displays their own drawbacks: important loss of zinc (jarosite, goethite), significant environmental impact of residue (jarosite) or economic cost (hematite). The work reported herein investigated the possibility of using phytic acid, a compound extractable from cereals, to remove iron. Precipitation was studied first at the laboratory-scale using DOE methodology and then with a laboratory pilot. At pH = 2.1, we showed that it is possible to remove up to 99.5% of iron with a loss of zinc equal to 0.6% and a residual concentration of FeIII of 130 mg L−1. Even if the amount of residue is more important than in the jarosite process, leaching tests showed that iron phytate could be stored in less drastic conditions than jarosite.