Exploring the synthesis, characterization, and corrosion inhibition of new tris-thiosemicarbazone derivatives for acidic steel settings using computational and experimental studies.

A novel two tri-thiosemicarbazones derivatives, namely 2,2',2''-((2-Hydroxybenzene-1,3,5-triyl)tris(methanylylidene))tris(N-benzylhydrazine-1-carbothioamide) (HBC) and 2,2',2''-((2-hydroxybenzene-1,3,5-triyl) tris (methanylylidene)) tris (N-allylhydrazine-1-carbothioamide) (HAC), have been synthesized and their chemical structures were determined using different spectroscopic and analytical approaches. Then, utilizing methods including open circuit potential, potentiodynamic polarization, and electrochemical impedance spectroscopy, the inhibitory effect of the synthesized thiosemicarbazones on mild steel (MS) in an acidic environment (0.5 M H2SO4) was thoroughly investigated. Remarkably, raising the concentration of our recently synthesized tri-thiosemicarbazones HBC and HAC increased the inhibitory efficiency values. The η values of the two investigated tri-thiosemicarbazones derivatives (HAC and HBC), at each concentration are extremely high, and the maximum values of the efficiencies are 98.5% with HAC and 98.8% with HBC at the 800 ppm. The inhibitors adsorbed on the mild steel surface and generated a charge and mass movement barrier that protected the metal from hostile ions. According to polarization curves, HBC and HAC act as mixed-type inhibitors. Electrochemical impedance testing revealed a notable rise in charge transfer resistance (Rct) readings to 4930-Ω cm2, alongside a reduction in the Constant Phase Element (CPE) value to 5.81 µF, suggesting increased effectiveness in preventing corrosion. Also, density functional theory (DFT) was applied to investigate the assembled tri-thiosemicarbazones HBC and HAC. Moreover, the adsorption mechanism of HBC and HAC on the mild steel surface was explored using Monte Carlo simulation. Finally, the theoretical outputs were discovered to support the practical outcomes.

Combination of practical and theoretical measurements of albumin egg as an eco-friendly inhibitor for copper corrosion in alkaline solutions.

Utilizing environmentally acceptable substances as inhibitors of metal corrosion is one of the most important strategies to reduce corrosion. In alkaline solutions (1.0 M KOH), the influence of albumin egg as a green corrosion inhibitor for copper was studied via a mix of experimental and theoretical investigations. Cyclic voltammetry (CV), open circuit potential (OCP), electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PDP), AFM, and SEM/EDX methods were all utilized to examine the inhibitory effect of albumin egg. By increasing the amount of albumin egg in the corrosive solution, the inhibition efficiency is increased. The albumin egg is a highly effective cathodic type inhibitor, according to electrochemical tests, with an inhibition efficiency of up to 94%. It also follows the Langmuir isotherm during adsorption. Investigations using SEM/EDX and AFM show that the albumin egg can create an adsorption layer on the surface enabling the shielding of the copper surface from harmful ions. In order to better understand the molecular structure of the albumin egg and its inhibitory action against corrosion, computational and molecular dynamics simulation techniques were also employed for calculating the electronic characteristics of inhibitor molecules. Calculations were made for total energy (TE), change in total energy (DET), energy gap (ΔE), ELUMO, EHOMO, dipole moment (D), and softness (δ). Utilizing the Monte Carlo simulation, the mechanism of albumin egg adsorption on the surface of Cu was investigated. The theoretical outcomes were found to confirm the empirical results.

Synthesis and applications of novel Schiff base derivatives as corrosion inhibitors and additives for improvement of reinforced concrete.

The studied Schiff-base compounds in this work are multitasked investigated as corrosion inhibitors and also, to improve the physical and mechanical properties of reinforced concrete. The efficiency inhibition of the two novel Schiff-base compounds named (DHSiMF) and (DHSiB) for corrosion of carbon-steel in aqueous media of 1 M HCl was assessed via electrochemical methods and loss in weight. FT-IR, 1H-NMR spectra and elemental analysis were used to confirm the structure of such compounds. It was found to have successful inhibition even at low concentrations in tested media, as an increase in inhibitor concentration led to an improvement in the inhibition efficiency. The weight loss results clearly demonstrate that DHSiMF of C-steel in 1 M HCl has a higher inhibition efficiency than DHSiB, with a maximum inhibition efficiency (85%) attained at 1 × 10-2 M from DHSiMF. Electrochemical experiments likewise revealed the same order, but with a maximal inhibitory efficiency of 98.1%. The addition of inhibitors to the corrosive media dramatically changed the anodic Tafel constants (ßa) and cathodic Tafel constants (ßc), indicating a mixed type nature. Electrochemical polarization curves illustrated the functions of mixed-type inhibition and the action of adsorption matching with the Langmuir adsorption isotherm. The ∆Gads values for DHSiMF and DHSiB at temperatures (ranging from 303 to 333 K) are - 34.42 kilojoule/mole to - 37.51 kilojoule/mole. These values indicate that the compounds' adsorption types are chemo-physical adsorption. X-ray diffraction (XRD) and Scanning electron microscopy (SEM) experiments were used to check the existence of the protection layer on the surface of carbon steel by analyzing the morphologies of the corrosion effects and the formed chemical compositions of the corrosion outcomes. For the concrete, the findings suggest that the chemical reaction that takes place between the DHSiMF and DHSiB and the concrete mix will result in an increase in the flexural strength, the compressive strength, and the indirect tensile strength of the concrete that is made of the gravel and dolomite aggregate.

Insights into the adsorption and corrosion inhibition properties of newly synthesized diazinyl derivatives for mild steel in hydrochloric acid: synthesis, electrochemical, SRB biological resistivity and quantum chemical calculations.

Two azo derivatives, 4-((4-hydroxy-3-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl) diazinyl) benzenesulfonic acid (TODB) and 4-((3-((4,4-dimethyl-2,6-dioxocyclohexylidene) methyl)-4-hydroxyphenyl)diazinyl) benzenesulfonic acid (DODB) were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H-NMR) and mass spectral studies. Gravimetric methods, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) techniques and inductive coupled plasma-optical emission spectroscopy were used to verify the above two compounds' ability to operate as mild steel (MS) corrosion inhibitors in 1 M HCl. Tafel data suggest that TODB and DODB have mixed-type characteristics, and EIS findings demonstrate that increasing their concentration not only alters the charge transfer (R ct) of mild steel from 6.88 Ω cm2 to 112.9 Ω cm2 but also changes the capacitance of the adsorbed double layer (C dl) from 225.36 to 348.36 µF cm-2. At 7.5 × 10-4 M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate.

Wooden Polymer Composites of Poly(vinyl chloride), Olive Pits Flour, and Precipitated Bio-Calcium Carbonate.

As a filler to be inserted into poly(vinyl chloride) (PVC), low-cost olive pits flour (OPF) and precipitated bio-calcium carbonate (PBCC)-produced PVC/OPF/PBCC composites have been used with high stability and rigidity compared to PVC. Hydrogen bonding is generated between OH cellulose in OPF and H in PVC. Composite tensile modulus increased in PVC grid in the presence of PBCC and OPF, possibly because of a filler restriction effect on the polymer chains. The hardness also increased as both OPF and PBCC increased. The mechanical tendency of the PVC/OPF composite was improved by adding a low content of PBCC particles with the PVC network, resulting in a smart distribution in the range of 10% by weight, and it was reduced by adding more than that percentage. The successful distribution of PBCC in PVC/OPF composite strengthened the mechanical path. The morphology and possible interface adhesion of components in the composite were demonstrated by scanning electron microscopy (SEM). The PVC SEM images showed a homogeneous, smart, and consistent surface, while the PVC/60 wt % OPF SEM images showed a large number of voids that suggested weak PVC/OPF interactions. The SEM images showed outstanding PBCC distribution in the PVC/OPF matrix for the PVC/50 wt % OPF/10 wt % PBCC composite. Due to the accumulation of PBCC particles producing cavities, the distribution of particles became nonhomogeneous at percentages above 10 wt %. At a low filler material, better spread of PBCC particles in the PVC grid was achieved. Owing to the polarity of OPF, the H2O absorption and thickness swelling of PVC/OPF/PBCC composites showed higher amounts than PVC. PBCC improved the thermal stabilization and the neutralization of Cl- negative ions as an acid acceptor of secondary PVC stabilization.

Ethanedihydrazide as a Corrosion Inhibitor for Iron in 3.5% NaCl Solutions.

Corrosion of iron in sodium chloride (3.5% wt) solutions and its inhibition by ethanedihydrazide (EH) have been reported. Electrochemical impedance spectroscopy (EIS), cyclic potentiodynamic polarization (CPP), and change of current with time at -475 mV (Ag/AgCl) measurements were employed in this study. Scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) techniques were utilized to report surface morphology and elemental analysis, respectively. The presence of 5 × 10-5 M EH was found to inhibit the corrosion of iron, and the effect of inhibition profoundly increased with an increase in EH concentration up to 1 × 10-4 M and further to 5 × 10-4 M. The low values of corrosion current and high corrosion resistance, which were obtained from the EIS, CPP, and change of current with time experiments, affirmed the adequacy of EH as a corrosion inhibitor for iron. Surface investigations demonstrated that the chloride solution without EH molecules causes severe corrosion, while the coexistence of EH within the chloride solution greatly minimizes the acuteness of chloride, particularly pitting corrosion.

Anticorrosion Effect of Ethoxylate Sulfanilamide Compounds on Carbon Steel in 1 M Hydrochloric Acid: Electrochemical and Theoretical Studies.

Metal corrosion is an important economic problem globally. One of the best ways to protect metal surfaces from corrosion is by the use of corrosion inhibitors, especially surfactants. This study assesses anticorrosion properties of three inhibitor compounds (S1, S2, and S3) of ethoxylate sulfanilamide containing 2, 10, and 20 units of ethylene oxide on carbon steel in 1 M HCl solution. The anticorrosive performance of S1, S2, and S3 was studied using potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), adsorption isotherm, surface tests (scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectroscopy, and X-ray diffraction (XRD) analysis), and computational studies (density functional theory (DFT) and molecular dynamics (MD) simulations) within the concentration range of 10-6 to 10-2 M at 30 ± 2 °C. The results of the methods used indicate that increasing the concentration of the inhibitor compounds improves the effectiveness of inhibition (from 50.9 to 98%), whereas the inhibition efficiency order for ethoxylated sulfanilamide compounds is S2 > S3 > S1 with the highest inhibiting efficiency, respectively, of 98.0, 95.0, and 90.0% for 10-2 M. Also, PDP indicated that S1, S2, and S3 inhibitors act as mixed-type inhibitors and their adsorption obeys the Langmuir adsorption isotherm model. Surface tests show that the studied compounds can significantly inhibit acid attack via chemical adsorption on the metal. Furthermore, all of the chemical descriptors derived from DFT indicate that the three inhibitors are quite well adsorbed by the adhesion centers on the CS surface. The three compounds' molecular geometries and electronic structures were calculated using quantum chemical calculations. Using theoretical computations, the energy difference between the highest occupied molecular orbital and the lowest occupied molecular orbital has been determined to represent chemical reactivity and kinetic stability of a composition.