Directory

Emeka Oguzie | FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA - Academia.edu

Skip to main content

Emeka Oguzie

FEDERAL UNIVERSITY OF TECHNOLOGY, OWERRI, NIGERIA, Department of Chemistry,, Faculty Member

Followers

84

Following

13

Co-authors

2

Public Views

Web Page: www.emru-futo.com

less

JAMIU KOLAWOLE ODUSOTE

University of Ilorin

Sodiya Ezekiel Folorunso

Talabi Segun Isaac

University of Ilorin, Ilorin Kwara State Nigeria

olamide olawale

Landmark University

Engr Yusuf Lanre Shuaib-babata

The Federal Polytechnic, Ado-Ekiti, NIGERIA

sciepub.com SciEP

Covenant University Canaanland, Ota.

Federal University of Technology Akure

Edo State Institute Of Technology And Management Usen

Interests

Uploads

Papers by Emeka Oguzie

Corrosion inhibition of mild steel in acidic media by some organic dyes

Materials Letters, 2005

Inhibition of corrosion of mild steel in sulphuric acid by acidic extract of Jatropha Curcas leav... more Inhibition of corrosion of mild steel in sulphuric acid by acidic extract of Jatropha Curcas leaves has been studied using weight loss and thermometric measurements. It was found that the leaves extract act as a good corrosion inhibitor for mild steel in all concentrations of the extract. The inhibition action depends on the concentration of the Jatropha Curcas leaves extract in the acid solution. Results for weight loss and thermometric measurements indicate that inhibition efficiency increase with increasing inhibitor concentration. The adsorption of Jatropha curcas leaves extract on the surface of the mild steel specimens obeys Langmuir adsorption isotherm. Based on the results, Jatropha curcas leaves extract is recommended for use in industries as a replacement for toxic chemical inhibitors.

Inhibition of Mild Steel Corrosion in HCl Solution by Pentaclethra macrophylla Bentham Extract

by Israel Owate and Emeka Oguzie

The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild stee... more The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl was investigated by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy, and UV-visible analysis. The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60°C and then drops to 93 % at 70°C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic partial reactions. Impedance results indicate that chitosan was adsorbed on the metal/ solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism.

Experimental and theoretical assessment of the inhibiting action of Aspilia africana extract on corrosion aluminium alloy AA3003 in hydrochloric acid

by CHIDIEBERE MADUABUCHI and Emeka Oguzie

The adsorption of Aspilia africana extract and subsequent corrosion inhibition of aluminium alloy... more The adsorption of Aspilia africana extract and
subsequent corrosion inhibition of aluminium alloy AA3003
in hydrochloric acid solutions have been investigated using
gravimetric and electrochemical techniques. Inhibition
efficiency increased with extract concentration and temperature
rise. Polarization studies revealed that the extract
essentially inhibited the cathodic reaction. An adsorption
mechanism involving physisorption and chemisorption of
extract constituents at low and high temperatures, respectively,
has been proposed from the trend of adsorption-free
energies. Quantum chemical computations and molecular
dynamics simulations described the individual contributions
of some extract constituents to the observed inhibiting
effect.

Phytochemical screening on the leaves of Sansevieria trifasciata

J. Chem. Soc. Nigeria, Jan 1, 2004

Extract of Allium cepa and Allium sativum as corrosion inhibitors of mild steel in HCl solution

Transactions of the SAEST, Jan 1, 2006

Adsorption and corrosion-inhibiting effect of Dacryodis edulis extract on low-carbon-steel corrosion in acidic media

Journal of colloid and …, Jan 1, 2010

The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H 2 SO 4 by extracts of Dacryod... more The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H 2 SO 4 by extracts of Dacryodis edulis (DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic matter onto the steel surface in a concentration-dependent manner and involved both protonated and molecular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract.

Electronic structure of monomeric water adsorption on Ni {111}: Beyond the general model

The Journal of Physical …, Jan 1, 2008

The adsorption of an H 2 O molecule on Ni{111} has been investigated by density functional theory... more The adsorption of an H 2 O molecule on Ni{111} has been investigated by density functional theory (DFT) calculations. In addition to the consensus between previously reported experimental data and our DFT results arrived at via the surface relaxation pattern, the electron work function and energy levels of a free H 2 O, as well as the adsorption energy, we have further presented a previously unrecognized electronic picture for the stable on-top adsorption, by analysis of projected density of states. We have provided clear evidence that the Ni 3p orbitals (p z and p y ), specifically the hybrid orbitals: 3p z -2p z , 3p y -2p z , 3p z -2p y , and 3p y -2p y , play crucial roles in the water bonding at the surface. Our results thus offer a new and inclusive understanding of the electronic nature, which is beyond the conventional model of 3a 1 -3p z and 3a 1 -3p y interactions.

Ground water contamination: A simulation study of buried waste metallic contaminant penetration through the aquifers

J. Chem. Soc. Nig, Jan 1, 2002

Corrosion and corrosion inhibition characteristics of bulk nanocrystalline ingot iron in sulphuric acid

Journal of Solid State …, Jan 1, 2008

The corrosion and corrosion inhibition of bulk nanocrystalline ingot iron (BNII) fabricated from ... more The corrosion and corrosion inhibition of bulk nanocrystalline ingot iron (BNII) fabricated from conventional polycrystalline ingot iron (CPII) by severe rolling was studied in 0.5 M H 2 SO 4 solution using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicate that BNII was more susceptible to corrosion in the acidic environment essentially because of an increase in the kinetics of the anodic reaction. An amino acid cysteine (cys) was employed as a corrosion inhibitor at concentrations of 0.001 and 0.005 M. Tests in inhibited solutions revealed that cys reduced the corrosion rates of both metal specimens by different mechanisms. For CPII cys inhibited the cathodic reaction but had a stimulating effect on the anodic process at low concentration and a trivial effect at higher concentration. For BNII, cys inhibited both the cathodic and the anodic reactions, although the former effect was more pronounced. Iodide ions improved the inhibitive effect of cys without altering the inhibition mechanism.

Inhibition of corrosion of aluminum in alkaline solution by methylene blue

Bulletin of …, Jan 1, 2004

Corrosion inhibition properties of thiosemicarbozone and semicarbazone derivatives in concentrated acid environment

Global Journal of Pure …, Jan 1, 2008

Influence of iron microstructure on corrosion inhibitor performance in acidic media

The Journal of Physical …, Jan 1, 2009

Electrochemical measurements employing ac and dc techniques as well as atomic force microscopy we... more Electrochemical measurements employing ac and dc techniques as well as atomic force microscopy were used to study the electrochemical corrosion behavior of ingot iron with two different microstructures: conventional polycrystalline ingot iron (CPII) and bulk nanocrystalline ingot iron (BNII) fabricated from CPII by severe rolling, without and with inhibitors. The corrosive media was 0.1 M H 2 SO 4 solution, while thiourea (TU) was employed as inhibitor, with a concentration of 5.0 mM, as well as a 1:1 combination of TU and KI. Impedance and polarization results show that BNII was more susceptible to corrosion in the uninhibited acid. The presence of TU improved the corrosion resistance of both specimens comparably, while KI reduced the inhibition efficiency of TU. Infrared spectrophotometry revealed that the interfacial species for CPII and BNII in the presence of TU were quite identical and markedly different from that in TU + KI. Molecular dynamics (MD) simulations were performed to illustrate the adsorption process of TU at a molecular level, and the theoretical predictions showed good agreement with the electrochemical results.

Corrosion inhibition of mild steel in 1 MH2so4 by polyvinyl pyrrolidone and synergistic iodide additives

Portugaliae Electrochimica Acta, Jan 1, 2008

The corrosion inhibition of mild steel in 1M H 2 SO 4 by polyvinyl pyrrolidone (PVP) and the syne... more The corrosion inhibition of mild steel in 1M H 2 SO 4 by polyvinyl pyrrolidone (PVP) and the synergistic effect of iodide ions were investigated using weight loss and hydrogen evolution methods in the temperature range of 30 -60 o C. The corrosion rates of mild steel decreased with the increasing concentration of PVP, while the inhibition efficiency (%I) increased. The inhibition efficiency of PVP decreased with rise in temperature, suggesting a physical adsorption mechanism, which was found to follow Freundlich and Temkin adsorption isotherms. The inhibition mechanism was further collaborated by the values of kinetics/thermodynamic parameters obtained from the experimental data. The inhibiting action of PVP was considerably enhanced in the presence of iodide ions and values of the synergism parameter (S 1 ) obtained point to synergistic interactions between PVP and iodide ions.

Inhibition of mild steel corrosion in acidic media by aqueous extracts from Garcinia kola seed

Bulletin of …, Jan 1, 2006

The extract from the seeds of Garcinia kola was investigated as a corrosion inhibitor for mild st... more The extract from the seeds of Garcinia kola was investigated as a corrosion inhibitor for mild steel in 2M HCl and 1M H 2 SO 4 solutions using the gasometric technique. The results indicate that the extract inhibited the metal corrosion in the acidic environments and inhibition efficiency increased with concentration. Temperature studies revealed a decrease in efficiency with rise in temperature and corrosion activation energies increased in the presence of the extract. A mechanism of physical adsorption is proposed for the inhibition behaviour.

Corrosion inhibition and adsorption behaviour of bismark brown dye on aluminium in sodium hydroxide solution

Materials Letters, Jan 1, 2006

The adsorption and corrosion inhibition of bismark brown (BB) on aluminium (AA 1060) in 0.1 M sod... more The adsorption and corrosion inhibition of bismark brown (BB) on aluminium (AA 1060) in 0.1 M sodium hydroxide solutions was studied at 25 and 70°C using gravimetric technique. The results indicate that BB acts as an inhibitor in the alkaline environment by adsorption on the metal surface and the inhibition efficiency was found to increase with dye concentration. The adsorption of BB on the aluminium surface has been discussed vis-à-vis the variation of inhibition efficiency with temperature as well as kinetic and activation parameters evaluated from the experimental data.

The inhibition of aluminium corrosion in potassium hydroxide by “Congo Red” dye, and synergistic action with halide ions

Anti-Corrosion Methods …, Jan 1, 2005

Purpose -To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in st... more Purpose -To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the inhibition efficiency. Design/methodology/approach -Corrosion rates of aluminium test coupons were determined by gravimetric technique at 30 and 608C. Inhibition efficiencies of the additives (0.01-5.0 mM CR and 5.0 mM CR þ 0.5 mM halides) were evaluated by comparing corrosion rates of the test coupons in 2 M KOH solution in the absence and presence of the additives. Findings -CR inhibited aluminium corrosion in 2 M KOH by physical adsorption of the dye molecules on the corroding metal surface. Maximum efficiency at 30 and 608C was 31.72 and 19.32 per cent, respectively. Dye adsorption was enhanced in the presence of halides in the order KCl , KBr , KI, with KI increasing efficiency up to 48.63 and 41.70 per cent at 30 and 608C, respectively.

Effect of< IT> Gongronema latifolium</IT> extract on aluminium corrosion in acidic and alkaline media

Pigment & Resin …, Jan 1, 2007

Purpose -This paper aims to appraise the effectiveness of Gongronema latifolium extract as an env... more Purpose -This paper aims to appraise the effectiveness of Gongronema latifolium extract as an environmentally friendly corrosion inhibitor for aluminium in strong acid (2 M HCl) and alkaline (2 M KOH) environments. Design/methodology/approach -Corrosion rates were determined using the gas-volumetric technique. The efficiency of inhibition was estimated by comparing corrosion rates in absence and presence of the additive, while the mechanism of inhibition was assessed by considering temperature effects on corrosion and inhibition processes. Findings -The results show that the extract was well adsorbed on the metal surface and significantly repressed aluminium corrosion in both environments. Inhibition efficiency generally increased with concentration up to maximum values of 97.54 and 90.82 per cent in 2 M HCl and 2 M KOH, respectively. Temperature dependence studies revealed that the extract was chemically adsorbed on the aluminium surface at all concentrations in 2 M HCl and physically adsorbed in 2 M KOH, with likely tendency to become chemisorbed at higher concentration. Originality/value -Gongronema latifolium has been studied for the first time as an inhibitor of aluminium corrosion and the results suggest that the extract could find practical application in corrosion control in aqueous acidic and alkaline environments. The findings are particularly useful, considering the scarcity of reports on the effective inhibition of aluminium corrosion in strong alkaline solutions.

Monitoring the corrosion susceptibility of mild steel in varied soil textures by corrosion product count technique

Materials chemistry and …, Jan 1, 2004

The corrosion susceptibilities of buried steel in natural soil and laboratory simulated buried st... more The corrosion susceptibilities of buried steel in natural soil and laboratory simulated buried steel in varied soil textures were monitored by weight loss and corrosion product count technique. The result shows that the corrosion product counts in these soils are in the order: clay sand < loam. Adsorption dynamics revealed that Weber and Morris equation was obeyed in all soil textures studied while the applicability of Lagergren equation was limited to sandy and clay soil textures. Also, in the absence of insidious ions, fairly identical pH values, limited aeration and moisture laden, soil depth and textures were corroborated for the observed high corrosion susceptibility of the buried steel.

Effect of hexamethylpararosaniline chloride (crystal violet) on mild steel corrosion in acidic media

Corrosion Science, Jan 1, 2008

The corrosion inhibition of mild steel in 0.5 M H 2 SO 4 and 1 M HCl by hexamethylpararosaniline ... more The corrosion inhibition of mild steel in 0.5 M H 2 SO 4 and 1 M HCl by hexamethylpararosaniline chloride (HMPC) was investigated using the gravimetric technique in the temperature range 303-333 K. The results indicate that HPMC inhibited the corrosion reaction in both acid media at all temperatures and inhibition efficiency increased with HMPC concentration. The inhibiting action is attributed to general adsorption of protonated and molecular HPMC species on the corroding metal surface. Adsorption followed a modified Langmuir isotherm and the Temkin isotherm, with very high negative values of the free energy of adsorption (DG 0 ads ). An increase in temperature reduced the inhibition efficiency of HPMC in 0.5 M H 2 SO 4 but increased efficiency in 1 M HCl. Activation parameters such as activation energy (E a ), activation enthalpy (DH * ) and activation entropy (DS * ) as well as the adsorption heat (Q ads ) were evaluated from the effect of temperature on corrosion and inhibition processes.

Corrosion inhibition and adsorption behaviour of< IT> Ocimum basilicum</IT> extract on aluminium

Pigment & resin …, Jan 1, 2006

Purpose -To appraise the inhibiting effect of Ocimum basilicum extract on aluminium corrosion in ... more Purpose -To appraise the inhibiting effect of Ocimum basilicum extract on aluminium corrosion in 2 M HCl and 2 M KOH solutions, respectively, at 30 and 608C. Design/methodology/approach -Corrosion rates were determined using the gas-volumetric technique and the values obtained in absence and presence of extract was used in calculation of the inhibition efficiency. The mechanism of inhibition was estimated from the trend of inhibition efficiency with temperature. Findings -Ocimum basilicum extract was found to inhibit aluminium corrosion in the acidic and alkaline environments. Inhibition efficiency increased with extract concentration but decreased with rise in temperature, suggesting physical adsorption of the organic matter on the metal surface. These results were corroborated by kinetic and activation parameters for corrosion and adsorption processes evaluated from the experimental data at the temperatures studied. Halide additives synergistically improved the inhibition efficiency of the extract. Originality/value -This paper provides new information on the possible application of Ocimum basilicum extract as an environmentally friendly corrosion inhibitor. The mixed extract -iodide formulation provides an effective means for retarding aluminium corrosion even in highly aggressive alkaline environments.

Corrosion inhibition of mild steel in acidic media by some organic dyes

Materials Letters, 2005

Inhibition of corrosion of mild steel in sulphuric acid by acidic extract of Jatropha Curcas leav... more Inhibition of corrosion of mild steel in sulphuric acid by acidic extract of Jatropha Curcas leaves has been studied using weight loss and thermometric measurements. It was found that the leaves extract act as a good corrosion inhibitor for mild steel in all concentrations of the extract. The inhibition action depends on the concentration of the Jatropha Curcas leaves extract in the acid solution. Results for weight loss and thermometric measurements indicate that inhibition efficiency increase with increasing inhibitor concentration. The adsorption of Jatropha curcas leaves extract on the surface of the mild steel specimens obeys Langmuir adsorption isotherm. Based on the results, Jatropha curcas leaves extract is recommended for use in industries as a replacement for toxic chemical inhibitors.

Inhibition of Mild Steel Corrosion in HCl Solution by Pentaclethra macrophylla Bentham Extract

by Israel Owate and Emeka Oguzie

The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild stee... more The efficiency of chitosan (a naturally occurring polymer) as a corrosion inhibitor for mild steel in 0.1 M HCl was investigated by gravimetric, potentiodynamic polarization, electrochemical impedance spectroscopy measurements, scanning electron microscopy, and UV-visible analysis. The polymer was found to inhibit corrosion even at a very low concentration. Inhibition efficiency increases with a rise in temperature up to 96 % at 60°C and then drops to 93 % at 70°C, while it slightly increases with an increase in chitosan concentration. Polarization curves indicate that chitosan functions as a mixed inhibitor, affecting both cathodic and anodic partial reactions. Impedance results indicate that chitosan was adsorbed on the metal/ solution interface. Adsorption of chitosan at the mild steel surface is found to be in agreement with Langmuir adsorption isotherm model. Chemical adsorption is the proposed mechanism for corrosion inhibition considering the trend of protection efficiency with temperature. Calculated kinetic and thermodynamic parameters corroborate the proposed mechanism.

Experimental and theoretical assessment of the inhibiting action of Aspilia africana extract on corrosion aluminium alloy AA3003 in hydrochloric acid

by CHIDIEBERE MADUABUCHI and Emeka Oguzie

The adsorption of Aspilia africana extract and subsequent corrosion inhibition of aluminium alloy... more The adsorption of Aspilia africana extract and
subsequent corrosion inhibition of aluminium alloy AA3003
in hydrochloric acid solutions have been investigated using
gravimetric and electrochemical techniques. Inhibition
efficiency increased with extract concentration and temperature
rise. Polarization studies revealed that the extract
essentially inhibited the cathodic reaction. An adsorption
mechanism involving physisorption and chemisorption of
extract constituents at low and high temperatures, respectively,
has been proposed from the trend of adsorption-free
energies. Quantum chemical computations and molecular
dynamics simulations described the individual contributions
of some extract constituents to the observed inhibiting
effect.

Phytochemical screening on the leaves of Sansevieria trifasciata

J. Chem. Soc. Nigeria, Jan 1, 2004

Extract of Allium cepa and Allium sativum as corrosion inhibitors of mild steel in HCl solution

Transactions of the SAEST, Jan 1, 2006

Adsorption and corrosion-inhibiting effect of Dacryodis edulis extract on low-carbon-steel corrosion in acidic media

Journal of colloid and …, Jan 1, 2010

The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H 2 SO 4 by extracts of Dacryod... more The inhibition of low-carbon-steel corrosion in 1 M HCl and 0.5 M H 2 SO 4 by extracts of Dacryodis edulis (DE) was investigated using gravimetric and electrochemical techniques. DE extract was found to inhibit the uniform and localized corrosion of carbon steel in the acidic media, affecting both the cathodic and anodic partial reactions. The corrosion process was inhibited by adsorption of the extracted organic matter onto the steel surface in a concentration-dependent manner and involved both protonated and molecular species. Molecular dynamics simulations were performed to illustrate the process of adsorption of some specific components of the extract.

Electronic structure of monomeric water adsorption on Ni {111}: Beyond the general model

The Journal of Physical …, Jan 1, 2008

The adsorption of an H 2 O molecule on Ni{111} has been investigated by density functional theory... more The adsorption of an H 2 O molecule on Ni{111} has been investigated by density functional theory (DFT) calculations. In addition to the consensus between previously reported experimental data and our DFT results arrived at via the surface relaxation pattern, the electron work function and energy levels of a free H 2 O, as well as the adsorption energy, we have further presented a previously unrecognized electronic picture for the stable on-top adsorption, by analysis of projected density of states. We have provided clear evidence that the Ni 3p orbitals (p z and p y ), specifically the hybrid orbitals: 3p z -2p z , 3p y -2p z , 3p z -2p y , and 3p y -2p y , play crucial roles in the water bonding at the surface. Our results thus offer a new and inclusive understanding of the electronic nature, which is beyond the conventional model of 3a 1 -3p z and 3a 1 -3p y interactions.

Ground water contamination: A simulation study of buried waste metallic contaminant penetration through the aquifers

J. Chem. Soc. Nig, Jan 1, 2002

Corrosion and corrosion inhibition characteristics of bulk nanocrystalline ingot iron in sulphuric acid

Journal of Solid State …, Jan 1, 2008

The corrosion and corrosion inhibition of bulk nanocrystalline ingot iron (BNII) fabricated from ... more The corrosion and corrosion inhibition of bulk nanocrystalline ingot iron (BNII) fabricated from conventional polycrystalline ingot iron (CPII) by severe rolling was studied in 0.5 M H 2 SO 4 solution using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicate that BNII was more susceptible to corrosion in the acidic environment essentially because of an increase in the kinetics of the anodic reaction. An amino acid cysteine (cys) was employed as a corrosion inhibitor at concentrations of 0.001 and 0.005 M. Tests in inhibited solutions revealed that cys reduced the corrosion rates of both metal specimens by different mechanisms. For CPII cys inhibited the cathodic reaction but had a stimulating effect on the anodic process at low concentration and a trivial effect at higher concentration. For BNII, cys inhibited both the cathodic and the anodic reactions, although the former effect was more pronounced. Iodide ions improved the inhibitive effect of cys without altering the inhibition mechanism.

Inhibition of corrosion of aluminum in alkaline solution by methylene blue

Bulletin of …, Jan 1, 2004

Corrosion inhibition properties of thiosemicarbozone and semicarbazone derivatives in concentrated acid environment

Global Journal of Pure …, Jan 1, 2008

Influence of iron microstructure on corrosion inhibitor performance in acidic media

The Journal of Physical …, Jan 1, 2009

Electrochemical measurements employing ac and dc techniques as well as atomic force microscopy we... more Electrochemical measurements employing ac and dc techniques as well as atomic force microscopy were used to study the electrochemical corrosion behavior of ingot iron with two different microstructures: conventional polycrystalline ingot iron (CPII) and bulk nanocrystalline ingot iron (BNII) fabricated from CPII by severe rolling, without and with inhibitors. The corrosive media was 0.1 M H 2 SO 4 solution, while thiourea (TU) was employed as inhibitor, with a concentration of 5.0 mM, as well as a 1:1 combination of TU and KI. Impedance and polarization results show that BNII was more susceptible to corrosion in the uninhibited acid. The presence of TU improved the corrosion resistance of both specimens comparably, while KI reduced the inhibition efficiency of TU. Infrared spectrophotometry revealed that the interfacial species for CPII and BNII in the presence of TU were quite identical and markedly different from that in TU + KI. Molecular dynamics (MD) simulations were performed to illustrate the adsorption process of TU at a molecular level, and the theoretical predictions showed good agreement with the electrochemical results.

Corrosion inhibition of mild steel in 1 MH2so4 by polyvinyl pyrrolidone and synergistic iodide additives

Portugaliae Electrochimica Acta, Jan 1, 2008

The corrosion inhibition of mild steel in 1M H 2 SO 4 by polyvinyl pyrrolidone (PVP) and the syne... more The corrosion inhibition of mild steel in 1M H 2 SO 4 by polyvinyl pyrrolidone (PVP) and the synergistic effect of iodide ions were investigated using weight loss and hydrogen evolution methods in the temperature range of 30 -60 o C. The corrosion rates of mild steel decreased with the increasing concentration of PVP, while the inhibition efficiency (%I) increased. The inhibition efficiency of PVP decreased with rise in temperature, suggesting a physical adsorption mechanism, which was found to follow Freundlich and Temkin adsorption isotherms. The inhibition mechanism was further collaborated by the values of kinetics/thermodynamic parameters obtained from the experimental data. The inhibiting action of PVP was considerably enhanced in the presence of iodide ions and values of the synergism parameter (S 1 ) obtained point to synergistic interactions between PVP and iodide ions.

Inhibition of mild steel corrosion in acidic media by aqueous extracts from Garcinia kola seed

Bulletin of …, Jan 1, 2006

The extract from the seeds of Garcinia kola was investigated as a corrosion inhibitor for mild st... more The extract from the seeds of Garcinia kola was investigated as a corrosion inhibitor for mild steel in 2M HCl and 1M H 2 SO 4 solutions using the gasometric technique. The results indicate that the extract inhibited the metal corrosion in the acidic environments and inhibition efficiency increased with concentration. Temperature studies revealed a decrease in efficiency with rise in temperature and corrosion activation energies increased in the presence of the extract. A mechanism of physical adsorption is proposed for the inhibition behaviour.

Corrosion inhibition and adsorption behaviour of bismark brown dye on aluminium in sodium hydroxide solution

Materials Letters, Jan 1, 2006

The adsorption and corrosion inhibition of bismark brown (BB) on aluminium (AA 1060) in 0.1 M sod... more The adsorption and corrosion inhibition of bismark brown (BB) on aluminium (AA 1060) in 0.1 M sodium hydroxide solutions was studied at 25 and 70°C using gravimetric technique. The results indicate that BB acts as an inhibitor in the alkaline environment by adsorption on the metal surface and the inhibition efficiency was found to increase with dye concentration. The adsorption of BB on the aluminium surface has been discussed vis-à-vis the variation of inhibition efficiency with temperature as well as kinetic and activation parameters evaluated from the experimental data.

The inhibition of aluminium corrosion in potassium hydroxide by “Congo Red” dye, and synergistic action with halide ions

Anti-Corrosion Methods …, Jan 1, 2005

Purpose -To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in st... more Purpose -To investigate the inhibitive effect of Congo red dye (CR) for aluminium corrosion in strong alkaline solutions and evaluate the synergistic effect of halide ions on the inhibition efficiency. Design/methodology/approach -Corrosion rates of aluminium test coupons were determined by gravimetric technique at 30 and 608C. Inhibition efficiencies of the additives (0.01-5.0 mM CR and 5.0 mM CR þ 0.5 mM halides) were evaluated by comparing corrosion rates of the test coupons in 2 M KOH solution in the absence and presence of the additives. Findings -CR inhibited aluminium corrosion in 2 M KOH by physical adsorption of the dye molecules on the corroding metal surface. Maximum efficiency at 30 and 608C was 31.72 and 19.32 per cent, respectively. Dye adsorption was enhanced in the presence of halides in the order KCl , KBr , KI, with KI increasing efficiency up to 48.63 and 41.70 per cent at 30 and 608C, respectively.

Effect of< IT> Gongronema latifolium</IT> extract on aluminium corrosion in acidic and alkaline media

Pigment & Resin …, Jan 1, 2007

Purpose -This paper aims to appraise the effectiveness of Gongronema latifolium extract as an env... more Purpose -This paper aims to appraise the effectiveness of Gongronema latifolium extract as an environmentally friendly corrosion inhibitor for aluminium in strong acid (2 M HCl) and alkaline (2 M KOH) environments. Design/methodology/approach -Corrosion rates were determined using the gas-volumetric technique. The efficiency of inhibition was estimated by comparing corrosion rates in absence and presence of the additive, while the mechanism of inhibition was assessed by considering temperature effects on corrosion and inhibition processes. Findings -The results show that the extract was well adsorbed on the metal surface and significantly repressed aluminium corrosion in both environments. Inhibition efficiency generally increased with concentration up to maximum values of 97.54 and 90.82 per cent in 2 M HCl and 2 M KOH, respectively. Temperature dependence studies revealed that the extract was chemically adsorbed on the aluminium surface at all concentrations in 2 M HCl and physically adsorbed in 2 M KOH, with likely tendency to become chemisorbed at higher concentration. Originality/value -Gongronema latifolium has been studied for the first time as an inhibitor of aluminium corrosion and the results suggest that the extract could find practical application in corrosion control in aqueous acidic and alkaline environments. The findings are particularly useful, considering the scarcity of reports on the effective inhibition of aluminium corrosion in strong alkaline solutions.

Monitoring the corrosion susceptibility of mild steel in varied soil textures by corrosion product count technique

Materials chemistry and …, Jan 1, 2004

The corrosion susceptibilities of buried steel in natural soil and laboratory simulated buried st... more The corrosion susceptibilities of buried steel in natural soil and laboratory simulated buried steel in varied soil textures were monitored by weight loss and corrosion product count technique. The result shows that the corrosion product counts in these soils are in the order: clay sand < loam. Adsorption dynamics revealed that Weber and Morris equation was obeyed in all soil textures studied while the applicability of Lagergren equation was limited to sandy and clay soil textures. Also, in the absence of insidious ions, fairly identical pH values, limited aeration and moisture laden, soil depth and textures were corroborated for the observed high corrosion susceptibility of the buried steel.

Effect of hexamethylpararosaniline chloride (crystal violet) on mild steel corrosion in acidic media

Corrosion Science, Jan 1, 2008

The corrosion inhibition of mild steel in 0.5 M H 2 SO 4 and 1 M HCl by hexamethylpararosaniline ... more The corrosion inhibition of mild steel in 0.5 M H 2 SO 4 and 1 M HCl by hexamethylpararosaniline chloride (HMPC) was investigated using the gravimetric technique in the temperature range 303-333 K. The results indicate that HPMC inhibited the corrosion reaction in both acid media at all temperatures and inhibition efficiency increased with HMPC concentration. The inhibiting action is attributed to general adsorption of protonated and molecular HPMC species on the corroding metal surface. Adsorption followed a modified Langmuir isotherm and the Temkin isotherm, with very high negative values of the free energy of adsorption (DG 0 ads ). An increase in temperature reduced the inhibition efficiency of HPMC in 0.5 M H 2 SO 4 but increased efficiency in 1 M HCl. Activation parameters such as activation energy (E a ), activation enthalpy (DH * ) and activation entropy (DS * ) as well as the adsorption heat (Q ads ) were evaluated from the effect of temperature on corrosion and inhibition processes.

Corrosion inhibition and adsorption behaviour of< IT> Ocimum basilicum</IT> extract on aluminium

Pigment & resin …, Jan 1, 2006

Purpose -To appraise the inhibiting effect of Ocimum basilicum extract on aluminium corrosion in ... more Purpose -To appraise the inhibiting effect of Ocimum basilicum extract on aluminium corrosion in 2 M HCl and 2 M KOH solutions, respectively, at 30 and 608C. Design/methodology/approach -Corrosion rates were determined using the gas-volumetric technique and the values obtained in absence and presence of extract was used in calculation of the inhibition efficiency. The mechanism of inhibition was estimated from the trend of inhibition efficiency with temperature. Findings -Ocimum basilicum extract was found to inhibit aluminium corrosion in the acidic and alkaline environments. Inhibition efficiency increased with extract concentration but decreased with rise in temperature, suggesting physical adsorption of the organic matter on the metal surface. These results were corroborated by kinetic and activation parameters for corrosion and adsorption processes evaluated from the experimental data at the temperatures studied. Halide additives synergistically improved the inhibition efficiency of the extract. Originality/value -This paper provides new information on the possible application of Ocimum basilicum extract as an environmentally friendly corrosion inhibitor. The mixed extract -iodide formulation provides an effective means for retarding aluminium corrosion even in highly aggressive alkaline environments.