Inhibition Of Zinc Research Articles

Corrosion inhibition of zinc by Mansoa alliacea plant extract in sodium chloride media: Extraction, Characterization and Electrochemical Studies

Ethanol extract of Mansoa alliacea was tested as corrosion inhibitor for zinc in NaCl 3% media using polarization and electrochemical impedance spectroscopy (EIS). Potentiodynamic polarization curves indicated that the plant extract behaves as mixed-type inhibitor. Impedance measurements showed that there are two phenomena in the process of inhibition. The results obtained show that this plant extract could serve as an effective inhibitor for the corrosion of zinc in NaCl 3% media. The extract obtained give inhibition around 90%. The experimental data obtained from EIS method show a frequency distribution and therefore a modelling element with frequency dispersion behaviour, a constant phase element (CPEα,Q) has been used. Graphical methods are illustrated by synthetic data to determine the parameter of CPE (α, Q). Polarization curves show that Mansoa alliacea extract affects the anodic and cathodic reactions and the corrosion potential values were shifted to the positive potentials in the presence of the crude extract. Studies on the phytochemical constituents of the total extract were also established. Electrochemical studies, on the chemical families present in the crude extract, were also carried out to find the main constituents responsible for corrosion inhibition properties of the plant extract.

Corrosion inhibition of zinc by calcium exchanged beidellite clay mineral: A new smart corrosion inhibitor

The corrosion inhibition performances of zinc immersed in 0.1M NaCl solution with and without CaCl2, Na+ and Ca2+ exchanged beidellite (BDT) clay mineral picked up from Agadir bassin (Morocco) was studiedby potentiodynamic measurements and electrochemical impedance spectroscopy. The chemical and microanalysis of Na+-BDT and Ca2+-BDT by different techniques reveal basal distances of clays, of about 1.22 and 1.48nm respectively, consistent with the saturation of beidellite interlayer spaces with Na+ and Ca2+ ions surrounded by one and two equivalent layers of water respectively. EIS results and surface analysis show that Ca2+-BDT acts as a smart inhibitor on zinc surface by modifying the physicochemical parameters of electrolyte near the surface. The exchange reaction in BDT involves the concentration decrease or the “suppression” of Na+, CO32- and Cl− ions near the zinc surface.

Corrosion Inhibition of Zinc Using Some Phenylthiazole Derivatives in Hydrochloric acid Solutions

The inhibitive action of some phenylthiazole derivatives namely: 2-acetylamino-5-p-bromophenylazo-4-phenylthiazole (BPT), 2-acetylamino-5-p-methylphenylazo-4-phenylthiazole (MPT), 2-acetylamino-5-p-methoxyphenylazo-4-phenylthiazole (XPT) and 2-acetylamino-5-p-nitrophenylazo-4-phenylthiazole (NPT), on zinc corrosion in 0.2 M HCl has been studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS)and electrochemical frequency modulation (EFM) measurements. The results showed that the dissolution rate of zinc decreases with increasing the phenylthiazole derivatives concentration and decreases with raising temperature. Polarization curves indicated that the studied inhibitors act as mixed-type inhibitors. The adsorption of the investigated compounds follows Langmuir adsorption isotherm model. The thermodynamic parameters of adsorption and corrosion processes were determined and discussed.

Hydroxamates Inhibit EMMPRIN as well as ADAM17/TACE and MMPs

To study corneal wound healing, organ cultures were injured with nitrogen mustard (NM). This blistering agent causes the epithelium to separate from the stromal layer. Separation is in part due to the activation of ADAM17/TACE. We found that ADAM17 is activated in rabbit corneal organ cultures immediately after NM exposure, and remains activated even at 24 hr post exposure. To inhibit ADAM17 and promote epithelial‐stromal integrity after NM exposure, the hydroxamates olvanil OH (NDH4409) and retro olvanil 8 (NDH4417) were tested for their ability to inhibit ADAM17 and reduce collagen XVII cleavage. The hydroxamates were applied 4 times to organ cultures over the course of 22 hrs, beginning 2 hours post NM exposure. Epithelial‐stromal separation at 24 hr was significantly reduced by the hydroxamate treatments. Surprisingly, both drugs also reduced expression of the matrix metalloproteinase (MMP) inducer, EMMPRIN. Thus, the inhibition of MMP‐9 observed after hydroxamate treatment was likely caused by both direct inhibition of the catalytic zinc as well as the reduction of EMMPRIN. In conclusion, hydroxamates inactivate ADAM17, MMPs, and also preserve corneal epithelialstromal integrity by attenuating the vesicant‐induced upregulation of EMMPRIN. Supported by UMDNJ‐Rutgers Counteract Center of Excellence NIAMSD U54AR055073; NIH NEI EY009056; and NIEHS P30ES005022

Effects of Antioxidant Components of AREDS Vitamins and Zinc Ions on Endothelial Cell Activation: Implications for Macular Degeneration

To investigate whether the benefit of Age-Related Eye Disease Study (AREDS) formula multivitamins and zinc in the progression of age-related macular degeneration (AMD) may occur through inhibiting inflammatory events in the choroid. Mouse C166 endothelial cells (ECs) and, for some experiments, human retinal pigment epithelium (RPE)-choroid organ cultures were treated with AREDS multivitamin solution (MVS) or ZnCl(2). The cytotoxicity of MVS was evaluated using a lactate dehydrogenase colorimetric assay. Cell motility was assessed using a scratch assay. Macrophage adhesion to EC monolayers or ICAM-1 protein was determined after MVS and zinc treatment and with or without lipopolysaccharide (LPS). Quantitative reverse transcription PCR and Western blot analysis were used to determine the effects of MVS on the expression of proinflammatory molecules in treated and untreated cells. AREDS MVS and zinc did not affect C166 EC viability until the 56th hour after treatment. Scratch assays showed partial inhibition of MVS and zinc on EC migration. In cell adhesion assays, MVS and zinc decreased the number of macrophages bound to EC and to ICAM-1 protein. Quantitative PCR showed that LPS increased the expression of ICAM-1 in both C166 and human RPE-choroid cultures, which was partially offset by MVS and zinc. MVS and zinc also mitigated LPS-induced ICAM-1 protein expression on Western blot analysis. Treatment with AREDS MVS and zinc may affect both angiogenesis and endothelial-macrophage interactions. These results suggest that AREDS vitamins and zinc ions may slow the progression of AMD, in part through the attenuation of EC activation.

Potent inhibition of dinuclear zinc(II) peptidase, an aminopeptidase from Aeromonas proteolytica, by 8-quinolinol derivatives: inhibitor design based on Zn2+ fluorophores, kinetic, and X-ray crystallographic study

The selective inhibition of an aminopeptidase from Aeromonas proteolytica (AAP), a dinuclear Zn(2+) hydrolase, by 8-quinolinol (8-hydroxyquinoline, 8-HQ) derivatives is reported. We previously reported on the preparation of 8-HQ-pendant cyclens as Zn(2+) fluorophores (cyclen is 1,4,7,10-tetraazacyclododecane), in which the nitrogen and phenolate of the 8-HQ units (as well as the four nitrogens of cyclen) bind to Zn(2+) in a bidentate manner to form very stable Zn(2+) complexes at neutral pH (K (d) = 8-50 fM at pH 7.4). On the basis of this finding, it was hypothesized that 8-HQ derivatives have the potential to function as specific inhibitors of Zn(2+) enzymes, especially dinuclear Zn(2+) hydrolases. Assays of 8-HQ derivatives as inhibitors were performed against commercially available dinuclear Zn(2+) enzymes such as AAP and alkaline phosphatase. 8-HQ and the 5-substituted 8-HQ derivatives were found to be competitive inhibitors of AAP with inhibition constants of 0.16-29 μM at pH 8.0. The nitrogen at the 1-position and the hydroxide at the 8-position of 8-HQ were found to be essential for the inhibition of AAP. Fluorescence titrations of these drugs with AAP and an X-ray crystal structure analysis of an AAP-8-HQ complex (1.3-Å resolution) confirmed that 8-HQ binds to AAP in the "Pyr-out" mode, in which the hydroxide anion of 8-HQ bridges two Zn(2+) ions (Zn1 and Zn2) in the active site of AAP and the nitrogen atom of 8-HQ coordinates to Zn1 (Protein Data Bank code 3VH9).

Synthesis, structures, and urease inhibition of nickel(II), zinc(II), and cobalt(II) complexes with similar hydroxy-rich Schiff bases

Four new nickel(II), zinc(II), and cobalt(II) complexes, [Zn(L1)2] · H2O (1), [Ni(L1)2] · H2O (2), [Ni(L2)2] (3), and [Co(L3)2] · H2O (4), derived from hydroxy-rich Schiff bases 2-{[1-(5-chloro-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL1), 2-{[1-(2-hydroxy-3-methoxyphenyl)methylidene]amino}-2-ethylpropane-1,3-diol (HL2), and 2-{[1-(5-bromo-2-hydroxyphenyl)methylidene]amino}-2-methylpropane-1,3-diol (HL3) have been synthesized and characterized by elemental analyses, infrared spectroscopy, and single-crystal X-ray determination. Each metal in the complexes is six-coordinate in a distorted octahedral coordination. The Schiff bases coordinate to the metal atoms through the imino N, phenolate O, and one hydroxyl O. In the crystal structures of HL1 and the complexes, molecules are linked through intermolecular O–H···O hydrogen bonds, forming 1-D chains. The urease inhibitory activities of the compounds were evaluated and molecular docking study of the compounds with the Helicobacter pylori urease was performed.

Synergistic effect of polyethylene glycol 600 and polysorbate 20 on corrosion inhibition of zinc anode in alkaline batteries

Polyethylene glycol 600 (PEG 600) and polysorbate 20 (Tween 20) were used as a composite corrosion inhibitor of zinc in alkaline solution for the first time. The effects of the composite and individual inhibitors on corrosion inhibition of zinc were evaluated by weight-loss analysis and electrochemical methods including potentiodynamic, potentiostatic, and electrochemical impedance spectroscopic measurements. It was found that there was a synergistic effect between PEG 600 and Tween 20 on corrosion inhibition of zinc. The corrosion inhibition efficiency of the composite inhibitor, 500 ppm PEG 600 + 500 ppm Tween 20, was 89%, much higher than that of the individual inhibitor, 1000 ppm Tween 20 (71%) or 1000 ppm PEG 600 (55%). The battery (Zn/MnO2) discharge performance tests showed that the composite inhibitor reduced the self-discharge of zinc anode more effectively than the individual inhibitor. The synergistic mechanism between PEG 600 and Tween 20 was discussed.

Corrosion inhibition of zinc in tetra- n-butylammonium bromide aerated aqueous solution by benzotriazole and Na 3PO 4

The effect of benzotriazole (BTA), Na 3PO 4 and their mixture on the corrosion of zinc in 17 wt.% (0.534 mol l −1) tetra- n-butylammonium bromide (TBAB) aerated aqueous solution has been investigated by means of weight-loss test, potentiodynamic polarization test, electrochemical impedance spectroscopy (EIS) and SEM/EDX techniques. The experimental results showed that BTA or Na 3PO 4 or inhibitor mixture could protect zinc in aqueous TBAB solution. The inhibitor combinations led to higher efficiencies compared to those obtained when added individually. An inhibition efficiency of an inhibitor mixture consisting of 0.5 g l −1 BTA and 1 g l −1 Na 3PO 4 was more than 97%.

Blockade of presynaptic K ATP channels reduces the zinc-mediated posttetanic depression at hippocampal mossy fiber synapses

Zinc is one of the most abundant transition metals in the brain, being present in a variety of synaptic processes. The mossy fiber terminals in area CA3 of the hippocampus contain large amounts of vesicular zinc and have an extremely high density of ATP-sensitive potassium (KATP) channels. The activation of these channels by zinc leads to rapid hyperpolarization of these presynaptic terminals and inhibition of transmitter release. It has been previously shown that intense stimulation of the synapses between mossy fibers and CA3 pyramidal cells evokes a posttetanic depression of synaptic activity, accompanied by a decrease in presynaptic calcium and vesicular zinc signals. These results suggest a neuromodulatory role for zinc at these synapses, which could be mediated by inhibition of presynaptic voltage-dependent calcium channels (VDCCs) and/or activation of presynaptic KATP channels. In order to evaluate the contribution of the second mechanism we have applied multiple tetanic stimulations in the absence and presence of the KATP channel blocker tolbutamide. Under control conditions, it was observed that the delivery of six tetani caused a posttetanic depression of synaptic activity. In the presence of tolbutamide, the depression was smaller and had a shorter time course. A similar depression was also observed in the presynaptic zinc and calcium signals. These findings are in agreement with the hypothesis that the activation of KATP channels by tetanically released zinc leads to cell hyperpolarization and subsequent reduction of presynaptic calcium entry, followed by the inhibition of both zinc and glutamate release. Thus, these results suggest that the inhibition of mossy fiber synaptic transmission by intensely released zinc is partially mediated by the activation of KATP channels.

Study of the inhibition of the corrosion of copper and zinc in HNO3 solution by electrochemical technique and quantum chemical calculations

The corrosion inhibition of copper and zinc in 0.1M HNO3 by 1,2,3,4-tetrazole (TTZ) and some of its derivatives has been analysed in a comparative study. Two experimental techniques have been used such as weight-loss and electrochemical polarization measurements. The results obtained reveal that the addition of these compounds reduces preferentially the corrosion of Cu rather than that of Zn. The adsorption of tetrazolic compounds on a copper surface was more favourable than their adsorption on a zinc surface. Moreover the inhibition efficiency calculated for copper was found to attain 95% in the presence of 1-phenyl-5-mercapto-1,2,3,4-tetrazole (PMT) while it remains constant at 1% for all compounds tested using zinc as electrode. Relationship between molecular structure and their inhibition efficiency was elucidated by quantum chemical calculations using the density functional theory (DFT).

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 Using Some Phenylthiazole Derivatives in Hydrochloric acid Solutions

The inhibitive action of some phenylthiazole derivatives namely: 2-acetylamino-5-p-bromophenylazo-4-phenylthiazole (BPT), 2-acetylamino-5-p-methylphenylazo-4-phenylthiazole (MPT), 2-acetylamino-5-p-methoxyphenylazo-4-phenylthiazole (XPT) and 2-acetylamino-5-p-nitrophenylazo-4-phenylthiazole (NPT), on zinc corrosion in 0.2 M HCl has been studied using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS)and electrochemical frequency modulation (EFM) measurements. The results showed that the dissolution rate of zinc decreases with increasing the phenylthiazole derivatives concentration and decreases with raising temperature. Polarization curves indicated that the studied inhibitors act as mixed-type inhibitors. The adsorption of the investigated compounds follows Langmuir adsorption isotherm model. The thermodynamic parameters of adsorption and corrosion processes were determined and discussed.

Schiff bases of ethylenediamine/triethylenetetramine with benzaldehyde/cinnamic aldehyde/salicylaldehyde as corrosion inhibitors of zinc in sulphuric acid

PurposeA survey of technical literature indicates that there is a shortage of excellent corrosion inhibitors for zinc in non‐oxidizing acids, particularly sulphuric acid. This paper aims to describe the behaviour of ethylenediamine‐N‐N′‐dibenzylidene, ethylenediamine‐N‐N′‐disalicylidene, ethylenediamine‐N‐N′‐dicinnamylidene, triethylenetetramine tribenzylidene and triethylenetetramine trisalicylidene as corrosion inhibitors for zinc in sulphuric acid solutions. The objective of this research work also is to have an insight into the action mechanism of these inhibitors.Design/methodology/approachThe effect of the various parameters affecting the action of the above‐mentioned corrosion inhibitors has been studied using weight‐loss data and polarisation measurements. Adsorption data also were utilized.FindingsThe inhibitors showed excellent corrosion inhibition (>99 per cent) at effective inhibitor concentrations. The two salicylidenes were better corrosion inhibitors than were corresponding benzylidenes. It appeared from this study that an efficient inhibitor is characterised by a relatively greater decrease in free energy of adsorption, lower entropy of adsorption and relatively lower heat of adsorption. Basically, these inhibitors were cathodic, as was revealed by polarisation data, and the inhibitors followed Langmuir adsorption isotherm behaviour. In general, the conjoint action of the inhibitor and the cathodic current was synergistic.Research limitations/implicationsPowerful Schiff bases still need to be synthesized so as to be effective at extremely low concentrations. The behaviour with other metals and alloys in diverse media also requires to be investigated.Originality/valueVery few inhibitors demonstrate such excellent corrosion inhibition of zinc in aggressive corrosive media. Such detailed investigations on corrosion inhibitors are unusual.

Corrosion Inhibition of Zinc in KOH Solutions

The influence of electrolyte additions on the corrosion of zinc in aqueous solutions of KOH has been determined using electrochemical and nonelectrochemical techniques. These included anodic and cathodic polarization resistance and potentiodynamic method. The inhibitors studied included ZnO and tetra-alkylammonium bromides in different concentrations. From the data provided corrosion currents were calculated. The effectiveness of the inhibitors was compared and it was found that combinations of zinc oxide with tetra-alkylammonium salts were the most effective. Surface analysis obtained with scanning electron microscopy (SEM) revealed morphology characteristics developed at the zinc surface.

Phytotoxicity of nanoparticles: Inhibition of seed germination and root growth

Plants need to be included to develop a comprehensive toxicity profile for nanoparticles. Effects of five types of nanoparticles (multi-walled carbon nanotube, aluminum, alumina, zinc, and zinc oxide) on seed germination and root growth of six higher plant species (radish, rape, ryegrass, lettuce, corn, and cucumber) were investigated. Seed germination was not affected except for the inhibition of nanoscale zinc (nano-Zn) on ryegrass and zinc oxide (nano-ZnO) on corn at 2000 mg/L. Inhibition on root growth varied greatly among nanoparticles and plants. Suspensions of 2000 mg/L nano-Zn or nano-ZnO practically terminated root elongation of the tested plant species. Fifty percent inhibitory concentrations (IC 50) of nano-Zn and nano-ZnO were estimated to be near 50 mg/L for radish, and about 20 mg/L for rape and ryegrass. The inhibition occurred during the seed incubation process rather than seed soaking stage. These results are significant in terms of use and disposal of engineered nanoparticles.

Study of (3-mercaptopropyl)trimethoxysilane reactivity on zinc: Comparison with organothiol and organosilane thin films

To assess the reactivity of both terminal functions of the (3-mercaptopropyl)trimethoxysilane molecule, three types of zinc substrate (mechanically polished, electrochemically reduced and electrochemically oxidized) were modified concurrently by 1H,1H,2H,2H-perfluorooctyl-triethoxysilane and 1H,1H,2H,2H-perfluorooctanethiol. Surface characterization has been carried out with X-ray photoelectron spectroscopy, polarization modulation infrared reflection–absorption spectroscopy and contact angle measurements. Classical electrochemical techniques were employed to investigate corrosion inhibition of zinc along with thin films grafting. It is found that electrochemical oxidation enhances the grafting of the –Si(OCH 3) 3 groups while electrochemical reduction facilitates the formation of thiolate bonds, leading both to modified surfaces of much better quality compared to modified polished zinc samples.

Concerning the Efficiency of Corrosion Inhibitors as Given by SVET

The possibility of obtaining corrosion inhibition efficiency from the Scanning Vibrating Electrode Technique (SVET) is investigated. Results are compared with those obtained by Electrochemical Impedance Spectroscopy (EIS) for the inhibition of iron and zinc with cerium nitrate and 1H-benzotriazole. Examples of good and bad estimations are given and an interpretation for the discrepancies observed is advanced. Large deviations occur when corrosion products are formed since this leads to an underestimation of the currents measured by SVET. Visual inspection of the samples may identify the cases more susceptible to deviation. The approach discussed here can be used to obtain more quantitative information from SVET measurements but should not replace the traditional ways used to determine the inhibition efficiency.

Corrosion Inhibition of Zinc on HCl using Nypa fruticans Wurmb Extract and 1,5 Diphenyl Carbazone

The corrosion inhibition of zinc in hydrochloric acid by extract of Nypa Fruticans Wurmb was studied using weight loss techniques. Maximum inhibition efficiency (and surface coverage) was obtained at an optimum concentration. However increase in temperature decreased the inhibition efficiency at the temperature range studied. The inhibition action of Nypa Fruticans Wurmb extract compared closely to that of 1, 5 Diphenyl Carbazone (DPC). Optimum inhibition efficiency for zinc in the presence of Nypa Fruticans Wurmb extract was 36.43% and 40.70% with DPC. The phenomenon of physical adsorption has been proposed from the activation energy values (19.33 kJ mol-1 and 21.11 kJ mol-1) with Nypa Fruticans Wurmb extract and DPC respectively. A first order kinetics has been deduced from the kinetic treatment of the results. The heat of adsorption, Qad range from (-33.63 to - 58.52 kJ mo l-1) for both additives studied. Mean ΔGoads values (-7.82 to 8.68 kJ mol-1) are negative and suggestive of adsorption on metal surface. The data obtained from this study fits well into the Langmuir isotherm. Evidence is hereby provided to show that Nypa Fruticans Wurmb extract and DPC inhibits the corrosion of zinc comparatively. Journal of Applied Sciences and Environmental Management Vol. 8 (1) 2004:57 - 61