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Irene M. Mavridis - One of the best experts on this subject based on the ideXlab platform.
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NMR Detection of Simultaneous Formation of [2]- and [3]Pseudorotaxanes in Aqueous Solution between α-Cyclodextrin and Linear Aliphatic α,ω-Amino Acids, an α,ω-Diamine and an α,ω-DiAcid of Similar Length, and Comparison with the Solid-State Structures
The Journal of Organic Chemistry, 1999Co-Authors: Kyriaki Eliadou, Konstantina Yannakopoulou, Aliki Rontoyianni, Irene M. MavridisAbstract:The interactions of 11-Aminoundecanoic Acid (1), 12-aminododecanoic Acid (2), 1,12-diaminododecane (3), and 1,13-tridecanoic diAcid (4) with α-cyclodextrin (αCD) were studied in aqueous solution by NMR spectroscopy. The association modes were established with titration and continuous variation plots, variable temperature NMR spectra, and dipolar interactions as recorded in 2D ROESY spectra. The studies were carried out at pH 7.3 and 13.6. These long, linear bifunctional molecules were found to form simultaneously [2]- and [3]pseudorotaxanes with αCD in the aqueous solution. At the higher pH the 1:1 adducts were present at concentrations higher than at the neutral pH. The longer guests formed complexes enriched in the 2:1 constituent at both pH values. There were clear indications that the [2]pseudorotaxanes are present in two isomeric forms. The presence of isomers also in the [3]pseudorotaxanes was not ruled out. Various exchange rate regimes were observed; clearly in neutral solutions the formation of t...
Al-tabbaa A - One of the best experts on this subject based on the ideXlab platform.
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The efficiency of eco-friendly corrosion inhibitors in protecting steel reinforcement
2021Co-Authors: Zomorodian A, Bagonyi R, Al-tabbaa AAbstract:© 2021 Elsevier Ltd Reinforcing steel is used extensively in buildings to provide strength and integrity to the concrete structure. This material is, however, highly susceptible to corrosion in chloride-contaminated environments, which increases the risk of structural instability and failure. This work characterises the mechanisms and efficiency of corrosion protection offered by sodium nitrate, casein, and two amino Acids (11–aminoundecanoic Acid, and p–aminobenzoic Acid) in simulated concrete pore solutions with different contents of chloride ions. The performance of each inhibitor in the critical chloride concentration (Ccirt) was investigated using electrochemical techniques. Open circuit potential and linear polarisation were used to identify the Ccrit in synthetic pore solutions. Potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to evaluate the corrosion activities and the passivation mechanism of inhibitors in Ccrit. Results indicate that reinforcing steel can be protected through an appropriate selection of corrosion inhibitors. Among of the inhibitors studied here, casein demonstrated the highest corrosion inhibition efficiency with minimum current density of 9.19 × 10−8 μA/cm2 and inhibitor efficiency of more than 80%. Casein provides passivity to the reinforcing steel in the presence of the Ccirt in the pore solution
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The efficiency of eco-friendly corrosion inhibitors in protecting steel reinforcement
2021Co-Authors: Zomorodian A, Bagonyi R, Al-tabbaa AAbstract:Reinforcing steel is used extensively in buildings to provide strength and integrity to the concrete structure. This material is, however, highly susceptible to corrosion in chloride-contaminated environments, which increases the risk of structural instability and failure. This work characterises the mechanisms and efficiency of corrosion protection offered by sodium nitrate, casein, and two amino Acids (11–aminoundecanoic Acid, and p–aminobenzoic Acid) in simulated concrete pore solutions with different contents of chloride ions. The performance of each inhibitor in the critical chloride concentration (C ) was investigated using electrochemical techniques. Open circuit potential and linear polarisation were used to identify the C in synthetic pore solutions. Potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to evaluate the corrosion activities and the passivation mechanism of inhibitors in C . Results indicate that reinforcing steel can be protected through an appropriate selection of corrosion inhibitors. Among of the inhibitors studied here, casein demonstrated the highest corrosion inhibition efficiency with minimum current density of 9.19 × 10 μA/cm and inhibitor efficiency of more than 80%. Casein provides passivity to the reinforcing steel in the presence of the C in the pore solution. cirt crit crit cirt −8
Zomorodian A - One of the best experts on this subject based on the ideXlab platform.
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The efficiency of eco-friendly corrosion inhibitors in protecting steel reinforcement
2021Co-Authors: Zomorodian A, Bagonyi R, Al-tabbaa AAbstract:© 2021 Elsevier Ltd Reinforcing steel is used extensively in buildings to provide strength and integrity to the concrete structure. This material is, however, highly susceptible to corrosion in chloride-contaminated environments, which increases the risk of structural instability and failure. This work characterises the mechanisms and efficiency of corrosion protection offered by sodium nitrate, casein, and two amino Acids (11–aminoundecanoic Acid, and p–aminobenzoic Acid) in simulated concrete pore solutions with different contents of chloride ions. The performance of each inhibitor in the critical chloride concentration (Ccirt) was investigated using electrochemical techniques. Open circuit potential and linear polarisation were used to identify the Ccrit in synthetic pore solutions. Potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to evaluate the corrosion activities and the passivation mechanism of inhibitors in Ccrit. Results indicate that reinforcing steel can be protected through an appropriate selection of corrosion inhibitors. Among of the inhibitors studied here, casein demonstrated the highest corrosion inhibition efficiency with minimum current density of 9.19 × 10−8 μA/cm2 and inhibitor efficiency of more than 80%. Casein provides passivity to the reinforcing steel in the presence of the Ccirt in the pore solution
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The efficiency of eco-friendly corrosion inhibitors in protecting steel reinforcement
'Organisation for Economic Co-Operation and Development (OECD)', 2021Co-Authors: Zomorodian A, Bagonyi Regeane, Al-tabbaa AbirAbstract:Reinforcing steel is used extensively in buildings to provide strength and integrity to the concrete structure. This material is, however, highly susceptible to corrosion in chloride-contaminated environments, which increases the risk of structural instability and failure. This work characterises the mechanisms and efficiency of corrosion protection offered by sodium nitrate, casein, and two amino Acids (11–aminoundecanoic Acid, and p–aminobenzoic Acid) in simulated concrete pore solutions with different contents of chloride ions. The performance of each inhibitor in the critical chloride concentration (Ccirt) was investigated using electrochemical techniques. Open circuit potential and linear polarisation were used to identify the Ccrit in synthetic pore solutions. Potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to evaluate the corrosion activities and the passivation mechanism of inhibitors in Ccrit. Results indicate that reinforcing steel can be protected through an appropriate selection of corrosion inhibitors. Among of the inhibitors studied here, casein demonstrated the highest corrosion inhibition efficiency with minimum current density of 9.19×10-8 µA/cm2 and inhibitor efficiency of more than 80%. Casein provides passivity to the reinforcing steel in the presence of the Ccirt in the pore solution.EPSR
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The efficiency of eco-friendly corrosion inhibitors in protecting steel reinforcement
2021Co-Authors: Zomorodian A, Bagonyi R, Al-tabbaa AAbstract:Reinforcing steel is used extensively in buildings to provide strength and integrity to the concrete structure. This material is, however, highly susceptible to corrosion in chloride-contaminated environments, which increases the risk of structural instability and failure. This work characterises the mechanisms and efficiency of corrosion protection offered by sodium nitrate, casein, and two amino Acids (11–aminoundecanoic Acid, and p–aminobenzoic Acid) in simulated concrete pore solutions with different contents of chloride ions. The performance of each inhibitor in the critical chloride concentration (C ) was investigated using electrochemical techniques. Open circuit potential and linear polarisation were used to identify the C in synthetic pore solutions. Potentiodynamic polarisation and electrochemical impedance spectroscopy were performed to evaluate the corrosion activities and the passivation mechanism of inhibitors in C . Results indicate that reinforcing steel can be protected through an appropriate selection of corrosion inhibitors. Among of the inhibitors studied here, casein demonstrated the highest corrosion inhibition efficiency with minimum current density of 9.19 × 10 μA/cm and inhibitor efficiency of more than 80%. Casein provides passivity to the reinforcing steel in the presence of the C in the pore solution. cirt crit crit cirt −8
Zonghuai Liu - One of the best experts on this subject based on the ideXlab platform.
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exfoliation of layered double hydroxides by an electrostatic repulsion in aqueous solution
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2008Co-Authors: Wenyan Hou, Liping Kang, Runguang Sun, Zonghuai LiuAbstract:Abstract Ni/Fe layered double hydroxides (Ni/Fe LDHs) with 11-Aminoundecanoic Acid (AUA) as pillared species (Ni/Fe LDHs-AUA with Ni/Fe = 4) was prepared by a co-precipitation method. The prepared Ni/Fe LDHs-AUA material was successfully delaminated in an aqueous system by a novel host–guest repulsive interaction process. The delaminated LDHs nanosheets were confirmed by XRD, TG-DSC, TEM, AFM, and IR analyses. XRD measurement on the slurry centrifuged from the solution showed an amorphous halo and the crystalline phase of Ni/Fe LDHs-AUA lost its sharp reflections at pH value of 2.0. After freeze-drying the slurry, the broad pattern was converted into a basal diffraction pattern, indicating the restacking of delaminated nanosheets to restore the original stacked form. AFM images showed that a large part of Ni/Fe LDHs-AUA was delaminated into one elementary layer at least, and the delaminated nanosheets had disk-like shapes with a diameter of ca. 100 nm. IR results confirmed the AUA molecules released from the interlayer accompanied with the delamination process and they could not be restacked into the interlayer during freeze-drying the delaminated nanosheets.
Kyriaki Eliadou - One of the best experts on this subject based on the ideXlab platform.
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NMR Detection of Simultaneous Formation of [2]- and [3]Pseudorotaxanes in Aqueous Solution between α-Cyclodextrin and Linear Aliphatic α,ω-Amino Acids, an α,ω-Diamine and an α,ω-DiAcid of Similar Length, and Comparison with the Solid-State Structures
The Journal of Organic Chemistry, 1999Co-Authors: Kyriaki Eliadou, Konstantina Yannakopoulou, Aliki Rontoyianni, Irene M. MavridisAbstract:The interactions of 11-Aminoundecanoic Acid (1), 12-aminododecanoic Acid (2), 1,12-diaminododecane (3), and 1,13-tridecanoic diAcid (4) with α-cyclodextrin (αCD) were studied in aqueous solution by NMR spectroscopy. The association modes were established with titration and continuous variation plots, variable temperature NMR spectra, and dipolar interactions as recorded in 2D ROESY spectra. The studies were carried out at pH 7.3 and 13.6. These long, linear bifunctional molecules were found to form simultaneously [2]- and [3]pseudorotaxanes with αCD in the aqueous solution. At the higher pH the 1:1 adducts were present at concentrations higher than at the neutral pH. The longer guests formed complexes enriched in the 2:1 constituent at both pH values. There were clear indications that the [2]pseudorotaxanes are present in two isomeric forms. The presence of isomers also in the [3]pseudorotaxanes was not ruled out. Various exchange rate regimes were observed; clearly in neutral solutions the formation of t...
