Beslenme ve Diyetetik Bölümü Koleksiyonu

Permanent URI for this collectionhttps://hdl.handle.net/20.500.12514/223

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Adsorption and inhibition effect of 2,4-diamino-6-hydroxypyrimidine for mild steel corrosion in HCl medium: experimental and theoretical investigation
(SPRINGER HEIDELBERG, 2019) Yildiz, Resit; Yıldız, Reşit
2,4-Diamino-6-hydroxypyrimidine (2D6H) was examined as corrosion inhibitor of mild steel (MS) in 0.1M HCl using potentiodynamic measurements, linear polarization resistance (LPR), scanning electron microscopy, electrochemical experiments, and quantum chemical calculations. All measurements show that the corrosion inhibition effectiveness is forthright compared to the concentration of 2D6H ranging from 0.5 to 10.0mM. Adsorption of 2D6H on the MS surface in the presence of HCl is determined to obey Langmuir adsorption isotherm. The electronic features elucidated by quantum chemical calculations were associated with the experimental inhibition productivities. The mechanism of inhibition was revealed by E-pzc measurements.
Corrosion behavior of mild steel in 1 M HCl with Cyclotrichium niveum as a green inhibitor
(Elsevier, 2024) Yıldız, Reşit; Arslanhan, Selim; Döner, Ali; Baran, Mehmet Fırat; Yıldız, Reşit
Recently, green inhibitors are replacing classical inhibitors in the acid cleaning industry due to very low cost, environmentally friendly and none toxic. In this study, Cyclotrichium niveum is used as a potential green corrosion inhibitor to investigate the corrosion behavior of mild steel (MS) in chloride solution using electrochemical, morphological, structural and quantum chemical methods. Fifty-three flavonoids are detected in methanol extract of cyclotrichium niveum by LC/ESI-MS/MS. While icorr values decreased, Rp and inhibition efficiencies values derived from electrochemical impedance spectroscopy (EIS) and linear polarization resistance (LPR) increased in increasing inhibitor concentrations. Maximum inhibition efficiency is found to be 97.3%, that is the almost highest value, when compared to previous studies and plant extract is classified as a mixed type inhibitor with respect to the potentiodynamic polarization (PDP). The model that best fits the experimental values is the Langmuir isotherm. The temperature effect is also studied in the range of 25–55 ○C. Higher activation energy is obtained in the presence of inhibitor, suggesting that it acts as an efficient inhibitor by forming a physical barrier to the charge and mass transfer reaction, leading to reduction in corrosion rate. Scanning electron and atomic force microscopies showed the more uniform, crack and pits free structure, confirming that there is a protective film over the MS surface for inhibited solution. XPS analysis showed the existence of C, O, and Fe atoms on the MS surface. Quantum chemical calculation manifested the adsorption mechanism associated with the electronic structure of the molecules. The findings of this work can be applicable in chemical cleaning process with acid treatment.
Experimental and theoretical investigation of adsorption and inhibition properties of 2-Amino-1,3,5-triazine-4,6-dithiol against corrosion in hydrochloric acid solution on mild steel
(Elsevier, 2023) Arslanhan, Selim; Yıldız, Reşit; Döner, Ali; Yıldız, Reşit
In this work, 2-Amino-1,3,5-triazine-4,6-dithiol (2-ATD) as novel and high efficiency corrosion inhibitor has been investigated for mild steel (MS) corrosion in 0.5 M HCl solution using electrochemical methods, scanning electron microscopy (SEM), energy disperse X-ray spectroscopy (EDX), atomic force microscopy (AFM) and quantum chemical calculation methods. Potentiodynamic polarization (PDP) curves indicate that 2-ATD is mixed type inhibitor, corrosion inhibition efficiency increased with increasing inhibitor concentration and reached its value of 96.5%. Evolution of exposure time versus corrosion behavior of 2-ATD is examined in corrosive medium. While corrosion potential (Ecorr) shifted more negative values, polarization resistances (Rp) decreased after 120 h exposure time due to the corrosion process. H2 volume is measured in uninhibited and inhibited solutions (10 mM 2-ATD) after 120 h exposure time. Very low volume (3.6 mL cm-2) of H2 is obtained on MS electrode in inhibited solution after 120 h of exposure, indicating that 2-ATD covers the entire surface against aggressive attack and retards the both anodic dissolution of MS and cathodic hydrogen evolution reactions. The adsorption process proposal is the Langmuir isotherm which is most suitable. Adsorption and thermodynamic parameters show that 2-ATD has a strong adsorption effect onto MS surface and includes mixed adsorption style (physical and chemical). Corrosion current density increases with increasing temperature and high activation energy (Ea) proves the strong adsorption of 2-ATD on the MS surface. Anti-corrosion mechanism of 2-ATD is described more detail with the potential of zero charge method. SEM, EDX and AFM analysis support the obtained results of electrochemical methods and confirm the existence of protective layer and strong adsorption of 2-ATD on the MS surface. Chronoamperometry test shows that current densities are almost constant whole experiment in the presence of organic film. Finally, quantum chemical calculation method of 2-ATD in blank solution is performed to investigate the active sites for possible attachment with MS surface.
The Study of 2, 4-Diamino-6-methly-1, 3, 5-triazine on the Corrosion Inhibition of Mild Steel in The Hydrochloric Acid Medium: Integrated Theoretical and Experimental Investigations
(Bingol University, 2023) Yıldız, Reşit; Yıldız, Reşit
The aim of this study is the investigation of adsorption and corrosion behaviors of 2,4-Diamino-6-methly-1,3,5-triazine (2-DMT) on mild steel (MS) in 0.5 M HCI solution using many experimental and theoretical studies such as potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), adsorption isotherm, potential of zero charge (PZC), scanning electron (SEM), atomic force microscopies (AFM) and quantum chemical calculations. The results showed that 2-DMT has an outstanding anti-corrosion performance of 94.6% at an optimum concentration of 10 mM and the MS surface, which was exposed to the inhibited solution at 298 K, does not contain pits, cracks or deformations. Values of icorr are found to be 0.51, 0.22, 0.098, 0.072 and 0.039 mA cm-2 for blank solution and each concentration of 2-DMT. Hydrogen volumes are 90 and 4.6 mL cm-2 for blank solution and the existence of 10.0 mM 2-DMT, respectively. The observed adsorption is much more consistent with Langmuir. The high performance is explained by the effective adsorbing of organic matter to the MS surface. HOMO, LUMO energies and the energy gap (∆E) are -7.1980, -1.9959 and 5.2021 eV, respectively. Accordingly, it is suggested that this organic compound can be used in the industrial acid cleaning procedure.

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