Zinc In Acid Solution Research Articles

Pantoprazole Sodium as a Corrosion Inhibitor for Zinc in Acidic Solutions

Pantoprazole Sodium as a Corrosion Inhibitor for Zinc in Acidic Solutions

Sensitive Analysis of Nitroguanidine in Aqueous and Soil Matrices by LC-MS.

Nitroguanidine, a widely used nitramine explosive, is an environmental contaminant that is refractory, persistent, highly mobile in soils and aquifers, and yet under-researched. Nitroguanidine determination in water and soil poses an analytical challenge due its high hydrophilicity, low volatility, charge neutrality over a wide pH range, and low proton affinity which results in low electrospray interface (ESI)-MS sensitivity. A sensitive method for the determination of nitroguanidine in aqueous and soil matrices was developed. The method is based on reduction by zinc in acidic solution, hydrophobization by derivatization, preconcentration on C18 cartridge, and LC-MS quantification. The demonstrated limit of detection (LOD) reaches 5 ng/L and 22 ng/g in water and soil, respectively. Analysis of a contaminated site demonstrates that it is possible to map a contamination plume that extends over 1 km from the source of the contamination.

Benzimidazole derivatives as corrosion inhibitors for zinc in acid solution

The corrosion inhibition characteristics of 2-mercapto benzimidazole (MBI), 2-mercapto benzimidazolyl-ethyl acetate (MBEA), 2-hydroxy benzimidazole (HBI) and 2-hydroxy 5-nitro benzimidazole (HNBI) on zinc corrosion in 0.1 M hydrochloric acid were investigated by weight loss and potentiodynamic polarization techniques. The inhibition efficiency increased with increase in inhibitor concentration but decreased with increase in temperature. The adsorption of MBI and MBEA obeyed Langmuir’s adsorption isotherm but HBI and HNBI followed Temkin’s adsorption isotherm. Thethermodynamic functions for adsorption processes were evaluated. The existence of film on metal surface in presence of inhibitors was established by scanning electron microscopy (SEM) images.

Corrosion inhibition of Zinc by Imidazol in Acidic Media

The inhibitive effect of imidazol on the dissolution of Zn in (1M) HCl has been studied. The inhibion effect of imidazol ,protection efficiency and the corrosion rate of Zn in (1M) HCl were investigated at various concentrations (1x 10-3 – 5x10-3) M and tempearture range (285-328) K. The corrosion inhibitive of Zn by imidazol was studied using weight loss measurement and analytical titration of the amounts of dissolved zinc in acidic solution in presence and absent of imidazol. It was observed that imidazol led to protection efficiency reached to (88.93)% when (10)mM imidazol concentration was used. A linear relationship came true between (C/?) and (C); where (?) is the coverage of Zn surface by imidazol which could be obtained from the rate of corrosion in the presence and absent of inhibitor in the acid solution and (C) is the concentration of imidazol. This linear relationship indicate that the inhibition action occure via Langmiur adsorption mechanism. Eventually, the corrosion rates, activated energy ,Arrhenius constant, changes in free energy, enthalpy and entropy accompanying with imidazol adsorption on Zn surface were calculated.

Corrosion inhibition of Zinc by Imidazol in Acidic Media

The inhibitive effect of imidazol on the dissolution of Zn in (1M) HCl has been studied. The inhibion effect of imidazol ,protection efficiency and the corrosion rate of Zn in (1M) HCl were investigated at various concentrations (1x 10-3 – 5x10-3) M and tempearture range (285-328) K. The corrosion inhibitive of Zn by imidazol was studied using weight loss measurement and analytical titration of the amounts of dissolved zinc in acidic solution in presence and absent of imidazol. It was observed that imidazol led to protection efficiency reached to (88.93)% when (10)mM imidazol concentration was used. A linear relationship came true between (C/?) and (C); where (?) is the coverage of Zn surface by imidazol which could be obtained from the rate of corrosion in the presence and absent of inhibitor in the acid solution and (C) is the concentration of imidazol. This linear relationship indicate that the inhibition action occure via Langmiur adsorption mechanism. Eventually, the corrosion rates, activated energy ,Arrhenius constant, changes in free energy, enthalpy and entropy accompanying with imidazol adsorption on Zn surface were calculated.

CORROSION INHIBITION OF ZINC IN HYDROCHLORIC ACID MEDIUM USING UREA INHIBITOR

The corrosion behavior of Zn in 1 M HCl solution containing various concentration of Urea range (10-3→ 5x 10-3) M at temperature range (285-328) K was investigated. The corrosion inhibitive action of Urea on Zinc metal was studied using weight loss measurement and analytical titration of the amounts of dissolved Zinc in acidic solution in presence and absence of Urea , the results showed that Urea caused to protection efficiency reached to 88% when (50)mM Urea concentration was used . The coverage (θ) of metal surface by Urea could be obtained from the rate of corrosion in the presence and absence of Urea in the acid solution. A linear relationship was found to exist between the value of (C/ θ) and the corresponding Urea concentration (C) indicating that the inhibition action to occur via adsorption mechanism. Changes in the free energy, enthalpy and entropy associated with Urea adsorption have been determined. Apparent energies of activation have been calculated for the corrosion process of Zinc in the acid from corrosion rates and Arrhenius Plots.

Metallic Zinc Reduction of Disulfide Bonds between Cysteine Residues in Peptides and Proteins

The use of powdered metallic zinc in acidic solution for the reduction of disulfide bonds in peptides and proteins has been investigated. The method has several advantages over the traditional mere ...

Tertiary Arsines as Corrosion Inhibitors for Zinc in acid solution

AbstractTertiary arsines such as diphenylethyl arsine (DPEA), diphenylmethyl arsine (DPMA) and triphenyl arsine (TPA) have been used as corrosion inhibitors for zinc in perchloric acid solution. These inhibitors inhibit corrosion effectively even in traces. The percentage inhibitor efficiency of the inhibitors are in the order DPEA > DPMA > TPA. The effect of pH and temperature on the inhibitor efficiency is studied. Steady state anodic and cathodic polarization data reveal that tertiary arsines act as interfacial corrosion inhibitors for zinc in acidic solution. The apparent free energies of adsorption of inhibitors have been reported for different possible modes of adsorption.

Diphenylethylarsine as an interfacial corrosion inhibitor for zinc in perchloric acid solution

Diphenylethylarsine has been tested as a corrosion inhibitor for electropolished zinc in perchloric acid solution, using weight loss and polarization methods. The corrosion of zinc is reduced by 85% in the presence of 2 × 10 -4M diphenylethylarsine. Anodic and cathodic polarization data reveal that diphenylethylarsine acts as an interfacial corrosion inhibitor for zinc in acidic solution. The free energy of adsorption of diphenylethylarsine is reported for different concentrations of solution.

N-Decylamine as a Corrosion Inhibitor for Zinc in Acidic Solution

AbstractThe effect of n-decylamine (nDA) on the chemical dissolution and the anodic and cathodic polarisation of an electropolished zinc surface in an acidic chloride solution has been studied. nDA had a significant effect on the corrosion rate of zinc, maximum corrosion inhibition (90%) being observed at 10−3 M nDA. The weight loss measurements, and polarisation measurements, gave closely similar values for the surface coverage by nDA, the adsorption of which followed the Langmuir adsorption isotherm. nDA acts mainly as a cathodic inhibitor, but with a small degree of anodic control. The negative free energy of adsorption, and the high degree of protection, indicate the strong interaction between nDA and the zinc surface.

On the inverse-voltammetric determination of zinc in acidic solution

Zur Bestimmung kleiner Zinkmengen in salzsauren Losungen ist die inverse Wechselspannungsvoltammetrie geeignet. Besonderheiten des Einflusses der Elektrolysezeit und kleinerer Kupfergehalte werden beschrieben. Die Standardabweichung der Einzelbestimmung mit 50 ng Zn/ml betrug ± 1,6%.

Role of anions in the corrosion and corrosion-inhibition of zinc in aqueous solutions

The effect of SO 4 2−, Cl −, Br −, I −, ClO 4 −, NO 3 −, NO 2 −, WO 4 2−, H 2PO 4 −, HPO 4 2−, and CrO 4 2− on the corrosion of zinc in aqueous solutions was studied by measuring the potential of a pure zinc electrode in neutral, strongly-aerated solutions of these anions as a function of both time and electrolyte concentration. Steady-state potentials for the first six anions varied with concentration C according to: E = a - b log C where a and b are constants. These anions promote corrosion and the extent of corrosion-promotion is related to their catalytic effect on the reduction of oxygen in solution. At high dilutions NO 2 −, H 2PO 4 −, HPO 4 2− and CrO 4 2− develop potentials which are practically independent of concentration. Corrosion is assumed to occur at a rate equal to that of film repair by oxygen. At a certain salt content ennobling of the potential takes place and inhibition or passivation sets in. The corrosion of zinc in acid solutions of NO 3 −, SO 4 2−, Cl −, ClO 4 −, H 2PO 4 − and CrO 4 2− was also studied by the thermometric method. On the basis of Δ T-normality curves distinction can be made between corrosive NO 3 −, SO 4 2−, Cl − and ClO 4 − anions, on the one hand, and inhibiting H 2PO 2 − and bassivating CrO 4 2− anions, on the other.

リボフラビン誘導体の研究 (第3報)

Leucoriboflavin, reduced form of riboflavin, is easily oxidized to riboflavin when shaken with air. To retain the leuco state, riboflavin was reduced with sodium dithionite or with zinc in acid solution to the leuco compound and its acylation with acetic anhydride or benzoyl chloride gave leucoriboflavin acylate. These compounds were stable in solid state but were easily decomposed to riboflavin acylate on exposure to sunlight or by heating, regaining the yellow color. Several decomposition products of leucoriboflavin acylate are described.

Detection of Zinc with?-naphthoquinoline and thiocyanate

β-Naphthoquinoline with thiocyanate provides a sensitive crystal reaction for zinc in acid solution. Even at zinc concentrations as low as 1:200000, characteristic crystals of zinc hydrogenβ-naphthoquinoline thiocyanate are obtained in 2 N sulfuric acid solution. The test can be carried out in the presence of moderate amounts of barium (acetic acid solution of reagent), calcium, magnesium, beryllium, aluminum, chromium, cerium, lead (acetic acid solution), arsenic, manganese and nickel as well as the alkali metals. Cadmium in concentrations below 0,5 per cent does not interfere; ferric iron up to 1 per cent does not interfere if the test is carried out in 50 per cent phosphoric acid solution. Most other metals give precipitates with the reagent.