Zinc In Acidic Medium Research Articles

Corrosion Inhibition of Zinc in Acid Medium using some Novel Organic Compounds

Corrosion Inhibition of Zinc in Acid Medium using some Novel Organic Compounds

Corrosion Inhibition Potential of Ethanol Extract of Bryophyllum pinnatum Leaves for Zinc in Acidic Medium

The inhibitive and adsorption properties of ethanol extract of Bryophyllum pinnatum leaves were studied using weight loss, potentiodynamic polarization, Scanning Electron Microscopy (SEM) and Fourier transformed infra-red spectroscopy (FTIR) methods of monitoring corrosion. The results obtained, indicated that ethanol extracts of Bryophyllum pinnatum leaves is a good adsorption inhibitor for the corrosion of zinc in sulphuric acid solutions. The adsorption of the inhibitor on zinc surface was found to be spontaneous and supported the Langmuir adsorption model. From the calculated values of free energy of adsorption, the activation energy and the variation of inhibition efficiency with temperature, a physical adsorption mechanism has been proposed for the adsorption of ethanol extract of Bryophyllum pinnatum leaves on zinc surface. Results from potentiodynamic polarization study indicated that Bryophyllum pinnatum is a mixed-type corrosion inhibitor. Analysis of spectra obtained from Fourier transformed infra-red spectrophotometer (FTIR) revealed that some functional groups presence in the spectra of the inhibitors were missing in the spectra of the corrosion products which also indicated that there is an interaction between zinc and the inhibitor.

Corrosion inhibition behavior of Ketosulfone for Zinc in acidic medium

The corrosion inhibition behavior of Ketosulfone for zinc is investigated by polarization and AC-impedance techniques at 303-333K. The Tafel plots indicates that the Ketosulfone is a mixed type inhibitor. The interaction between metal and inhibitor is explained by Langmuir adsorption isotherm. DG 0 ads andDH 0 ads value indicates the electrostatic interactions between metal and inhibitor. Calculated activation parameters explains the corrosion process. SEM images show the difference between inhibited solutions and blank solution.

Inhibition Effect of an Anti-HIV Drug on the Corrosion of Zinc in Acidic Medium

Corrosion inhibition of zinc in 0.1 M HCl by Tenofovir Disproxil Fumarate (TDF) an anti-HIV drug has been investigated by using weight loss, potentiodynamic polarization and electrochemical impedance spectroscopy. The experimental results suggested the inhibition efficiency increases with the increase in inhibitor concentration up to 10 ppm. Polarization results revealed that TDF acts as a mixed type inhibitor. The effect of temperature on the corrosion behavior of zinc in the given temperature range from 303–333 K was studied. Adsorption of the inhibitor followed the Langmuir isotherm. Activation and thermodynamic adsorption parameters were calculated and discussed.

Adsorptive and DFT Studies of Some Imidazolium Based Ionic Liquids as Corrosion Inhibitors for Zinc in Acidic Medium

Adsorptive and DFT Studies of Some Imidazolium Based Ionic Liquids as Corrosion Inhibitors for Zinc in Acidic Medium

Molecular-Level Understanding of the Inhibition Efficiency of Some Inhibitors of Zinc Corrosion by Quantum Chemical Approach

2-[4-(Methylthio) phenyl] acetohydrazide (HYD) and 5-[4-(methylthio)benzyl]-4H-1,2,4-triazole-3-thiol (TRD) are compounds that contain methylthiophenyl moiety and substantially inhibit corrosion of zinc in acidic medium. The relationship between molecular structures and inhibition efficiencies of these intriguing inhibitors remains the subject of intense speculation, as introduction of thiophenyl group in strategic positions of many molecules alters their activity. We have performed density functional theory calculations at the B3LYP/6-311++G(d,p) level to analyze the inhibition mechanisms proposed for these compounds. In agreement with experiments, the results afford a full explanation of the highest efficiency observed for TRD in terms of electronic and structural characteristics.

Inhibition effects of acetyl coumarines and thiazole derivatives on corrosion of zinc in acidic medium

The corrosion inhibition characteristics of acetyl coumarine (AC), bromo acetyl coumarine (BAC) and thiazole derivatives (BTMQ and BTCQ) on the corrosion of zinc in 0·1 M HCl solution were investigated by weight loss, potentiodynamic polarization and impedance techniques. The inhibition efficiency increased with increase in inhibitor concentration upto 5 ×10 − 4 M, then gave almost same inhibition efficiency. The polarization measurements indicated the mixed nature of inhibitors. The adsorption of compounds obeyed Langmuir’s adsorption isotherm. The thermodynamic functions for adsorption processes were evaluated.

High-impact polystyrene/polyaniline membranes for acid solution treatment by electrodialysis: Preparation, evaluation, and chemical calculation

In this study different membranes were produced, aiming to evaluate their use in electrodialysis. These membranes were produced using conventional polymer (high-impact polystyrene) and polyaniline. The membrane characterization was done by FTIR spectroscopy, scanning electron microscopy (SEM), and thermogravimetry (TGA). The studies of the zinc and proton extraction ionic transport through the membranes were evaluated using a three-compartment cell. The results obtained using the produced membranes were compared to the results obtained with the commercial membrane Nafion 450. It was found that a synthesized membrane can be used to recover zinc in acid media. In addition, a preliminary computational essay about the structures of PAni and CSA is presented.

Rapid determination of formaldehyde and sulfur dioxide in food products and Chinese herbals

Simple, sensitive and rapid methods for the determination of formaldehyde and sulfur dioxide were developed. The formaldehyde determination is based on the reaction between formaldehyde and acetylacetone solution, producing yellow 3,5-diacetyl-l-1,4-dihydrolutidine. Sulfur dioxide was detected as the deoxidize of sulfurous acid by zinc in acidic medium, which produces sulfureted hydrogen that make lead acetate paper blackening due to lead sulfide formation. The detection limits were 0.8 μg mL −1 and 6.0 μg mL −1 for formaldehyde and sulfur dioxide, respectively. The linear range were 0.8–20.0 μg mL −1 for formaldehyde and 6.0–100.0 μg mL −1 for sulfur dioxide determination. The main advantages of the new analytical procedure are the low background level, high selectivity, and very little sample preparation for on-site analysis of formaldehyde and sulfur dioxide in food or Chinese herbal samples with reference color card for qualitative or semi-quantitative determination. The results from these methods correlated well with those obtained from the standard methods.

Ethoxylated fatty acids as inhibitors for the corrosion of zinc in acid media

The inhibition effect of ethoxylated fatty acids were used as inhibitors for the corrosion of zinc metal in 1.0 M hydrochloric and 1.0 M sulfuric acid solutions at various temperatures ranging from 25 to 55 °C is investigated by weight loss measurement and electrochemical methods. The protection efficiency depends upon the type and concentration of the inhibitor and the nature of the acid medium. In both acid solutions the protection efficiencies of the inhibitors decrease with the increase in temperature. The inhibition was assumed to occur via the adsorption of the fatty acid molecules on the metal surface. The thermodynamic functions of dissolution and adsorption processes were calculated and discussed.

Studies on the Inhibition Characteristics of Eriochrome Black-T during the Corrosion of Zinc in Acid Media

The corrosion of zinc in acidic medium in the presence of Eriochrome Black-T (EBT) as inhibitor has been studied at four temperatures (303, 313,323 and 333 K) by weight-loss method. The percent inhibiton efficiency, the rate of corrosion (mils per year) and the surface coverage have been evaluated. The heat of adsorption and the activation energy have also been calculated for the corrosion inhibition process. Finally, the free energy change for the corrosion inhibition process has been determined. It is observed that, EBT acts as a good inhibitor for the corrosion of zinc at low temperatures. At higher temperature and at lower concentrations (10 -9 M) it rather acts in a catalytic manner.

An improved method of phosphorus analysis in sea water

A reagent for the determination of phosphorus in sea water which contains Mo(VI) plus Mo(V) may be easily prepared by the reduction of Mo(VI) with metallic zinc in acid medium. This reagent is stable in the air for several months, and the development of the molybdenum blue colour is complete in 20 min at about 100°C; the colour is stable for at least a few months. The salt error is approximately 5 per cent with sea water of chlorinity 19 per milli. The interference due to either arsenate or silicate at their concentrations in sea water is negligible.

Contribution to the electrochemical behaviour of zinc electrode in pyridine media

Galvanostatic anodic polarization studies on zinc in the presence of pyridine reveal the appreciable influence of complex formation on the dissolution potential of zinc in acid media (pH 3·0 and 5·0). particularly at 10%,v/v pyridine concentrations. In neutral solutions the presence of pyridine at as low a concentration as 5% hampers the anodic oxidation of the metal. Anodic charging curves obtained in alkaline solutions (pH 9 and 11) reveal stages which plausibly correspond to the formation of insoluble hydroxy complexes of the probable formulae Zn(py) 2(OH) 2 and Zn(py) 4(OH) 2. These dissolve in the electrolyte on open-circuit. The stability of the complex species Zn(py) 1–4(ClO,) 2 was examined by cathodic reduction of their dilute aqueous solutions. In weak acidic media the discharge of zinc ions seems to be enhanced through protonation of pyridine. At pH 8, the main cathodic process is the discharge of water. This occurs at considerably negative potentials subjected to appreciable overpotential.