Corrosion inhibition of mild steel in hydrochloric acid solution by the expired Ampicillin drug.

This study examines the utilization of the expired drug, namely ampicillin, as a mild steel corrosion inhibitor in an acidic environment. The inhibitor was evaluated using weight loss and electrochemical measurement accompanied with surface analytical techniques. The drug showed a potential inhibitory efficiency of > 95% at 55 °C. The inclusion of the inhibitor increased the charge transfer resistance at the steel-solution interface, according to impedance analyses. According to potentiodynamic polarisation measurements, expired ampicillin drug significantly decreased the corrosion current density and worked as a mixed-type corrosion inhibitor. The Langmuir adsorption isotherm was followed by the adsorption of ampicillin drug on the steel substrate, exhibiting an association of physical and chemical adsorption mechanisms. The surface study performed using contact angle and scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) measurements supported the inhibitor adsorption on the steel substrate.

Metal/metal oxide-carbohydrate polymers framework for industrial and biological applications: Current advancements and future directions.

Recently, the development and consumption of metal/metal oxide carbohydrate polymer nanocomposites (M/MOCPNs) are withdrawing significant attention because of their numerous salient features. Metal/metal oxide carbohydrate polymer nanocomposites are being used as environmentally friendly alternatives for traditional metal/metal oxide carbohydrate polymer nanocomposites exhibit variable properties that make them excellent prospects for a variety of biological and industrial uses. In metal/metal oxide carbohydrate polymer nanocomposites, carbohydrate polymers bind with metallic atoms and ions using coordination bonding in which heteroatoms of polar functional groups behave as adsorption centers. Metal/metal oxide carbohydrate polymer nanocomposites are widely used in woundhealing, additional biological uses and drug delivery, heavy ions removal or metal decontamination, and dye removal. The present review article features the collection of some major biological and industrial applications of metal/metal oxide carbohydrate polymer nanocomposites. The binding affinity of carbohydrate polymers with metal atoms and ions in metal/metal oxide carbohydrate polymer nanocomposites has also been described.

Novel ZrO2-glycine nanocomposite as eco-friendly high temperature corrosion inhibitor for mild steel in hydrochloric acid solution.

We report the green synthesis of novel ZrO2-Glycine nanocomposite referred to as ZrO2-Gly NC followed by its characterization using X-ray diffraction (XRD), Fourier transforms infrared (FT-IR) spectroscopy, SEM/EDX, and transmission electron microscopy (TEM) techniques. Further, the inhibition effect of the varying concentration of ZrO2-Gly NC on the corrosion of mild steel (MS) in 1 M HCl was investigated by weight loss and electrochemical measurements at 40-80 °C. The percentage inhibition efficacy of NC increased with the increase of concentration and temperature and reached about 81.01% at 500 ppm at 70 °C which decreased at 80 °C and exhibited 73.5% inhibition efficiencies. According to the polarization measurements, the investigated ZrO2-Gly NC works as a mixed-type inhibitor with predominantly inhibiting cathodic reaction. Also, the adsorption isotherm analysis indicated that the adsorption was spontaneous and followed the Langmuir adsorption isotherm. Furthermore, the contact angle measurement revealed the water-repelling property of the investigated inhibitor. The surface morphological study via SEM-EDS micrograph affirmed the appearance of a smooth surface in presence of inhibited media suggesting the formation of protective film by the adsorption of ZrO2-Gly NC on the surface of the MS even at higher temperature.

An investigation on the synthesis, characterization and anti-corrosion properties of choline based ionic liquids as novel and environmentally friendly inhibitors for mild steel corrosion in 5% HCl.

The development of green corrosion inhibitors is a challenging task as it has to comply with strict environmental regulations. Ionic liquids (ILs) have recently been proposed as promising corrosion inhibitors. The present paper reports on two ILs designed to act as green and efficient high-temperature corrosion inhibitors. The prepared ILs, namely, choline formate (ChF) and choline acetate (ChA), are composed of biologically active ions. To elucidate their structure and corrosion inhibition effect on mild steel in 5% HCl the ILs were subjected to characterization tests like proton nuclear magnetic resonance (1H NMR), carbon nuclear magnetic resonance (13C NMR) and Fourier Transform infra-red (FT-IR) spectroscopy and corrosion tests like weight loss measurements, potentiodynamic polarization measurements (PDP), and electrochemical impedance spectroscopy (EIS). The effectiveness of the inhibition (%IE) increased with increasing concentrations and temperature up to 50 °C. ChF and ChA exhibited the highest inhibition efficacies of 96.9% and 99.5%, respectively at a temperature of 50 °C and concentration of 2 × 10-3 M. Above 50 °C their inhibition performance diminished, displaying an efficacy of 77.6% for ChF and 79.3% for ChA at 80 °C. The results of polarization measurements suggested mixed type behavior of inhibitors, and adsorption followed Langmuir adsorption isotherm. Furthermore, surface studies like scanning electron microscopy-energy dispersive spectroscopy (SEM-EDS) revealed protecting capability of the investigated inhibitors. FT-IR, and Raman spectroscopic studies revealed the adsorption of ILs on the Fe surface, and an ultra-violet visible (UV-vis.) spectroscopy study confirms the formation of Fe2+- ILs complex. X-ray Photoelectron Spectroscopy (XPS) was conducted to study the formation of corrosion products and protective film over the mild steel surface. Density functional theory (DFT) calculations and molecular dynamics (MD) simulations were also done to understand the inhibition mechanism of ILs.

Molecular binding interaction of pyridinium based gemini surfactants with bovine serum albumin: Insights from physicochemical, multispectroscopic, and computational analysis.

To study the interaction of the series of pyridinium based gemini surfactants (GS) (referred to as m-Py-m, m = 14, 16); 4,4'-(propane-1,3-diyl)bis(1-(2-(tetradecyloxy)-2-oxoethyl) dipyridinium chloride (14-Py-14), and 4,4'-(propane-1,3-diyl) bis(1-(2-(hexadecyloxy)-2-oxoethyl)dipyridinium chloride (16-Py-16) with bovine serum albumin (BSA), various physicochemical and spectroscopic tools such as tensiometry, steady-state fluorescence, synchronous fluorescence, pyrene fluorescence, UV-visible, far-UV circular dichroism (CD) were utilized at physiological pH (7.4) and 298 K in combination with computational molecular modeling analysis. The tensiometric results show significant modifications in interfacial and thermodynamic parameters for m-Py-m GS upon BSA combination, deciphering the gemini surfactant-BSA interaction. Steady-state fluorescence analysis evaluates the structural alterations of BSA with the addition of m-Py-m GS. The plots of Stern-Volmer, modified Stern-Volmer, and thermodynamic parameters were used to determine the binding type of m-Py-m GS to BSA. The synchronous fluorescence spectra state a mild effect of gemini surfactants on the emission intensity of tyrosine (Tyr) residues, on the other hand, tryptophan (Trp) residues showed a significant effect. Post addition of GS, the plot of pyrene fluorescence reveals the mild micropolarity fluctuations via the probe (pyrene) molecules encapsulated in BSA. UV-visible experiments support the complex formation between the BSA and m-Py-m GS. Far-UV CD measurements revealed the modifications in the secondary structure of protein produced by m-Py-m GS. Furthermore, we also used the computational molecular modeling for attaining deep insight into BSA and m-Py-m GS binding and the results are supported with our experimental results.

Molecular Interaction of Amino Acid-Based Gemini Surfactant with Human Serum Albumin: Tensiometric, Spectroscopic, and Molecular Docking Study.

Binding effect and interaction of N,N'-dialkyl cystine based gemini surfactant (GS); 2(C12Cys) with human serum albumin (HSA) were systematically investigated by the techniques such as surface tension measurement, UV-visible spectroscopy, fluorescence spectroscopy, circular dichroism (CD) spectroscopy, and molecular docking studies. The surface tension measurement exhibited that HSA shifted the critical micelle concentration of the 2(C12Cys) GS to the higher side that confirms the complex formation among 2(C12Cys) GS and HSA which was also verified by UV-visible, fluorescence, and CD spectroscopy. Increase in the concentration of 2(C12Cys) GS increases the absorption of the HSA protein but has a reverse effect on the fluorescence intensity. The analysis of UV-visible study with the help of a static quenching method showed that the value acquired for the bimolecular quenching constant (k q) quenches the intrinsic fluorescence of the HSA protein. Synchronous fluorescence spectrometry declared that the induced-binding conformational changes in HSA and CD results explained the variations in the secondary arrangement of the protein in presence of 2(C12Cys) GS. The present study revealed that the interaction between 2(C12Cys) GS and HSA is important for the preparation and properties of medicines. Molecular docking study provides insight into the specific binding site of 2(C12Cys) GS into the sites of HSA.

L-proline mixed with sodium benzoate as sustainable inhibitor for mild steel corrosion in 1M HCl: An experimental and theoretical approach.

Following standard experimental (gravimetric measurements, potentiodynamic polarization measurements, electrochemical impedance measurements, spectroscopic measurements, scanning electron microscopy technique) and theoretical (DFT) approach, inhibition effect of L-proline (LPr) and LPr mixed with sodium benzoate (LPr + NaBenz) for mild steel (MS) corrosion in 1M HCl was studied at 30, 40, 50 and 60 °C. The concentration of LPr was varied between 100-600 ppm, whereas that of NaBenz was fixed at 10 ppm. LPr lowered the corrosion rates of MS to a considerable extent. Corrosion mitigating efficacy of LPr is synergistically enhanced on adding NaBenz at all concentrations. Evaluation of polarization parameters suggested that both LPr and LPr + NaBenz act as mixed type inhibitor with more control on cathodic reaction whereas impedance parameters suggested inhibition of metal corrosion by adsorption at the MS/solution interface. Surface microscopic examination of corroded and uncorroded MS coupons supported the protective effect of adsorbed inhibitor layer at the MS surface. Spectroscopic studies are suggestive of the complex formation between inhibitor molecules and the metal. When LPr is combined with NaBenz, the corrosion inhibition rate was improved greatly. Corrosion mitigating efficacy of LPr or LPr mixed with NaBenz obtained by different techniques are in good agreement and correlate well with theoretical quantum chemical descriptors.

Sugar based N,N'-didodecyl-N,N'digluconamideethylenediamine gemini surfactant as corrosion inhibitor for mild steel in 3.5% NaCl solution-effect of synergistic KI additive.

The inhibitory behaviour of non-ionic sugar based N,N'-didodecyl-N,N'-digluconamideethylenediamine gemini surfactant, designated as Glu(12)-2-Glu(12) on mild steel (MS) corrosion in 3.5% NaCl at 30-60 °C was explored using weight loss, PDP, EIS and SEM/EDAX/AFM techniques. The compound inhibited the corrosion of mild steel in 3.5% NaCl and the extent of inhibition was dependent on concentration and temperature. The inhibiting action of Glu(12)-2-Glu(12) is synergistically enhanced on addition of potassium iodide (KI) at all concentrations and temperatures. The inhibiting formulation comprising of 2.5 × 10-3 mM of Glu(12)-2-Glu(12) and 10 mM of KI exhibits an inhibition efficiency of 96.9% at 60 °C. Quantum chemical calculations and MD simulation were applied to analyze the experimental data and elucidate the adsorption behaviour and inhibition mechanism of inhibitors. MD simulation showed a nearly parallel or flat disposition for Glu(12)-2-Glu(12) molecules on the MS surface providing larger blocking area to prevent the metal surface from corrosion.

N,N'-Dialkylcystine Gemini and Monomeric N-Alkyl Cysteine Surfactants as Corrosion Inhibitors on Mild Steel Corrosion in 1 M HCl Solution: A Comparative Study.

Gemini surfactant, N,N'-dialkylcystine 2(C12Cys), derived from cystine, and a monomeric N-alkyl cysteine counterpart, (C12Cys), were synthesized and purified. The characterization of surfactants 2(C12Cys) and (C12Cys) was made by Fourier transform infrared, 1H NMR, and elemental analysis. The effect of 2(C12Cys) and (C12Cys) on mild steel (MS) corrosion in 1 M HCl solution was explored as a function of their concentration and electrolyte temperature by means of gravimetric and electrochemical experiments (potentiodynamic polarization and Electrochemical impedance spectroscopy), surface analytical techniques (scanning electron microscopy (SEM)/energy dispersive X-ray spectroscopy (EDAX) and atomic force microscopy (AFM)) and theoretical study. The investigated compounds exhibited surface active properties and performed as good inhibitors for corrosion control of mild steel (MS) in acid solution. However, compared to monomeric (C12Cys), Gemini surfactant 2(C12Cys) showed high corrosion inhibiting ability at very low concentration. The EIS results revealed a greater charge transfer resistance in 2(C12Cys) solution compared to that in (C12Cys) solution. SEM/EDAX observations validate the development of an inhibitive film by the adsorbed molecules of surfactant on the MS surface. The AFM micrographs supported the SEM/EDAX results and exhibited a lowering in the roughness of the corroded MS surface in the presence of both (C12Cys) and 2(C12Cys) surfactants. Further, quantum chemical calculations and Monte Carlo simulations were used to study the dependence of corrosion inhibiting efficacy on the molecular structure and adsorption strength.