Ionic Liquids as Green Corrosion Inhibitors for Industrial Metals and Alloys

Present chapter describes recent advances in the field of development of ionic liquids as green and sustainable corrosion inhibitors for metals and alloys. The present chapter has been divided into several sections and subsections. Recently, development of the green and sustainable technologies for the corrosion prevention is highly desirable due to increasing ecological awareness and strict environmental regulations. In the last two decades, corrosion inhibition using ionic liquids has attracted considerable attention due to its interesting properties such as low volatility, non-inflammability, non-toxic nature, high thermal and chemical stability and high adorability. Several types of ionic liquids have been developed as “green corrosion inhibitors” for different metals and alloys such as mild steel, aluminum, copper, zinc, and magnesium in several electrolytic media. The ionic liquids are promising, noble, green and sustainable candidates to replace the traditional volatile corrosion inhibitors

Electrocatalysis of Lindane Using Antimony Oxide Nanoparticles Based-SWCNT/PANI Nanocomposites

This work describes the chemical synthesis of antimony oxide nanoparticles (AONPs), polyaniline (PANI), acid functionalized single-walled carbon nanotubes (fSWCNTs), and the nanocomposite (AONP-PANI-SWCNT) as catalyst for the trace detection of lindane. Successful synthesis of the nanomaterials was confirmed by Fourier transform infrared (FT-IR) spectroscopy, ultraviolet-visible (UV-Vis) spectroscopy, x-ray diffraction (XRD) spectroscopy, and scanning electron microscopy (SEM). Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used for investigating the electrochemical behavior of the modified electrodes in the ferrocyanide/ferricyanide ([Fe(CN)6]4−/[Fe(CN)6]3−) redox probe. GCE-AONP-PANI-SWCNT exhibited faster electron transport properties as well as higher electroactivity as compared to bare-GCE, GCE-AONPs, GCE-PANI, and GCE-SWCNT electrodes. Electrocatalytic studies further showed that GCE-AONP-PANI-SWCNT modified electrode was stable (after 20 scans) with only a small current drop in lindane (0.57%). The GCE-AONP-PANI-SWCNT electrode with low detection limit of 2.01 nM performed better toward the detection of lindane as compared to other studies in literature. The GCE-AONP-PANI-SWCNT electrode is highly selective toward the detection of lindane in the presence of various organic and inorganic interfering species. Real sample analysis of river water and tap water samples using the developed sensor gave satisfactory percentage recoveries therefore confirming the potential of the proposed sensor for practical application

Adsorption and corrosion inhibition potentials of salicylaldehyde-based Schiff bases of semicarbazide and p-toluidine on mild steel in acidic medium : experimental and computational studies

Experimental studies, supported by comprehensive density functional theory (DFT) and Monte Carlo simulation studies have been carried out on 2-(2-hydroxybenzylidene)hydrazinecarboxamide (SEMISCAD) and 2-((p-tolylimino)methyl)phenol (p-TOLUSCAD), to describe their corrosion inhibition potentials for mild steel in hydrochloric acid (HCl). The newly synthesized Schiff bases inhibit corrosion of mild steel in 1 M HCl, and their corrosion inhibition efficiencies increase with increase in concentration. Inhibition efficiencies of 79 % and 86 % were obtained for SEMISCAD and p-TOLUSCAD, respectively at 303 K and minute concentration (5 × 10-4 M). The results further revealed that p-TOLUSCAD could be an averagely efficient formulation to exhibit 50% inhibition efficiency, even at elevated temperature (343 K). Both compounds were found to inhibit corrosion at the anodic and cathodic sites on the steel, and they are therefore mixed-type inhibitors. Electrochemical impedance spectroscopy (EIS) data revealed the adsorptive nature of the molecules on the steel surface. SEMISCAD and p-TOLUSCAD inhibit steel corrosion by adsorbing at steel/HCl interface via physisorption and chemisorption mechanisms. Reactivity parameters predicted from DFT calculations suggested the involvement of protonated forms of the molecules in the inhibitive process, and p-TOLUSCAD as a potentially better corrosion inhibitor than SEMISCAD, which is also supported by the adsorption characteristics derived from Monte Carlo simulations.The National Research Foundation (NRF) of South Africahttps://www.elsevier.com/locate/surfinhj2021Chemistr

Adsorption and Quantum Chemical Studies on the Inhibition Potentials of Some Thiosemicarbazides for the Corrosion of Mild Steel in Acidic Medium

Three thiosemicarbazides, namely 2-(2-aminophenyl)-N phenylhydrazinecarbothioamide (AP4PT), N,2-diphenylhydrazinecarbothioamide (D4PT) and 2-(2-hydroxyphenyl)-N-phenyl hydrazinecarbothioamide (HP4PT), were investigated as corrosion inhibitors for mild steel in H2SO4 solution using gravimetric and gasometric methods. The results revealed that they all inhibit corrosion and their % inhibition efficiencies (%IE) follow the order: AP4PT > HP4PT > D4PT. The %IE obtained from the gravimetric and gasometric experiments were in good agreement. The thermodynamic parameters obtained support a physical adsorption mechanism and the adsorption followed the Langmuir adsorption isotherm. Some quantum chemical parameters were calculated using different methods and correlated with the experimental %IE. Quantitative structure activity relationship (QSAR) approach was used on a composite index of some quantum chemical parameters to characterize the inhibition performance of the studied molecules. The results showed that the %IE were closely related to some of the quantum chemical parameters, but with varying degrees. The calculated/theoretical %IE of the molecules were found to be close to their experimental %IE. The local reactivity has been studied through the Fukui and condensed softness indices in order to predict both the reactive centers and to know the possible sites of nucleophilic and electrophilic attacks

Can Taxpayers Stand Discrimination?: Lack of Standing and the Religious Freedom Restoration Act Permits the Executive Branch to Fund Discrimination Within Religious Organizations

The Density Functional Theory (DFT) and ab initio (HF and MP2) calculations were performed on the quinoline molecule (QL) and its derivatives, namely quinaldine (QLD) and quinaldic acid (QLDA) to investigate their possible role as corrosion inhibitors for mild steel in acidic medium. Calculations were done for non-protonated and protonated forms in vacuo and in water. Some quantum chemical parameters were calculated and discussed in order to provide insight into the reactivity and selectivity of the molecules. The performance of the different calculation methods were also compared with available experimental data. The results show that DFT/B3LYP basis set is adequate in describing the geometry and quantum chemical parameters of the studied systems. Both experimental and theoretical results established that QLDA has the highest inhibition efficiency. A comparison in the trends of the quantum chemical parameters in water solution and in vacuo shows minimal influence of the solvent effects

Metathesis of Fatty Acid Ester Derivatives in 1,1-Dialkyl and 1,2,3-Trialkyl Imidazolium Type Ionic Liquids

The self-metathesis of methyl oleate and methyl ricinoleate was carried out in the presence of ruthenium alkylidene catalysts 1–4 in [bmim] and [bdmim][X] type ionic liquids (RTILs) (X = PF6−, BF4− and NTf2−) using the gas chromatographic technique. Best catalytic performance was obtained in [bdmim][X] type ionic liquids when compared with [bmim][X] type ionic liquids. Catalyst recycling studies were also carried out in the room temperature ionic liquids (RTILs) with catalysts 1–4 in order to explore their possible industrial application

Comparative supercapacitive properties of asymmetry two electrode coin type supercapacitor cells made from MWCNTS/cobalt oxide and MWCNTs/iron oxide nanocomposite

Supercapacitive properties of synthesized metal oxide nanoparticles (MO) vis a vis iron oxides (Fe2O3) and cobalt oxide (Co3O4) nanoparticles integrated with multi-walled carbon nanotubes (MWCNT) in a two-electrode coin cell type asymmetry supercapacitor assembly was investigated. The synthesised MO and nanocomposite films were characterised using techniques such as transmission electron microscopy (TEM), scan electron microscopy (SEM), electron dispersive X-ray spectroscopy (EDX) and X-ray diffraction spectroscopy (XRD). The supercapacitance of the asymmetry MWCNT-MO based supercapacitor in 1 M H2SO4 and 1 M Na2SO4 electrolytes was measured using cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and galvanostatic constant current charge-discharge (CD) techniques. The asymmetry supercapacitors MWCNT-Fe2O3|MWCNT and MWCNT-Co3O4|MWCNT gave the highest specific capacitance (SC) values of 439.94 mFcm-2 (or 64.74 Fg-1) and 425.83 mFcm-2 (or 45.79 Fg−1) respectively in 1 M H2SO4 using charge-discharge technique. Results obtained from charge-discharge experiment are much higher compared with those obtained using the CV technique since it is the most reliable and accurate method. The values compared favorably and higher compared to those reported in literature using similar technique. MWCNT-Fe2O3|MWCNT cell gave specific power (SP) and specific energy (SE) of 19.31 Wkg-1 and 2.68 WhKg-1 respectively in 1 M H2SO4, while the energy deliverable efficiency (/%) of the cell is 99.6 and 91.3% in 1 M H2SO4 and 1 M Na2SO4 respectively.http://www.electrochemsci.orgam201

Electrochemical determination of serotonin in urine samples based on metal oxide nanoparticles/MWCNT on modified glassy carbon electrode

The electrochemical response of serotonin on the modified electrode based on multiwalled-carbon-nanotube (MWCNT) doped respectively with nickel, zinc and iron oxide nanoparticles coating on glassy carbon electrode (GCE) at physiological pH 7 was determined using cyclic voltammetry (CV) and square wave voltammetry (SWV). The modified GCE/MWCNT-metal oxide electrodes exhibited excellent electrocatalytic activity towards the detection of serotonin at large peak current and lower oxidation potentials compared to other electrodes investigated. The dynamic range for the serotonin determination was between 5.98 × 10−3 μM to 62.8 μM with detection limits 118, 129 and 166 nM for GCE/MWCNT-NiO, GCE/MWCNT-ZnO and GCE/MWCNT-Fe3O4 sensors respectively. GCE-MWCNT-NiO was the best electrode in terms of serotonin current response, electrode stability, resistance to fouling and limit of detection towards the analyte. The developed sensors were found to be electrochemically stable, reusable, economically effective due to their extremely low operational cost, and have demonstrated good limit of detection, sensitivity and selectivity towards serotonin determination in urine samples. Keywords: Metal oxides nanoparticles, Multiwalled carbon nanotubes, Glassy carbon electrode, Serotonin, Cyclic voltammetry, Square wave voltammetr