Yazar "Haldhar, Rajesh" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • Küçük Resim Yok
    Öğe
    An effective and smart corrosion inhibitor in acidic environment: Experimental & theoretical studies
    (Korean Institute Chemical Engineers, 2023) Bouoidina, Asmae; Haldhar, Rajesh; Salim, Rajae; Ech-chihbi, Elhachmia; Ichou, Hamza; El-Hajjaji, Fadoua; Kim, Seong-Cheol
    The application of corrosion inhibitors is the best way to protect metals from degradation. Therefore, the P-anisidine molecule was investigated as a corrosion inhibitor for mild steel in a 1 M HCl medium. This study used different methods, such as electrochemical impedance spectroscopy, polarization potentiodynamic curves, scanning electron microscopy, and theoretical method. The addition of this molecule to the aggressive medium achieved inhibition of 81% at a concentration of 10(-3)M. The potentiodynamic polarization curves reveal a mixed type character (anodic and cathodic) and adsorb on the metal surface according to Langmuir adsorption isotherm. This adsorption was also proved by scanning electron microscopy proving the presence of a protective layer on the steel surface used. The theoretical results confirmed the experimental part and showed that P-anisidine adsorbed parallel onto the steel surface covering a large surface area.
  • Küçük Resim Yok
    Öğe
    Corrosion inhibition, surface adsorption and computational studies of Momordica charantia extract: a sustainable and green approach
    (Springer International Publishing Ag, 2021) Haldhar, Rajesh; Prasad, Dwarika; Kamboj, Divya; Kaya, Savas; Dagdag, Omar; Guo, Lei
    The aerial parts extract of Momordica charantia plant were used for the corrosion resistance of carbon steel in the acidic medium (0.5 M H2SO4) utilizing weight loss method, Tafel and Electrochemical Impedance Spectroscopy. The state of mixed inhibitor adsorption on the carbon steel surface is shown by potentiodynamic polarization. M. charantia achieved the extraordinary inhibition efficiency of 93.51% at 500 mg/L of inhibitor concentration. Scanning electron microscopy and atomic force microscopy were used to know about the thin layer which was formed on the surface of carbon steel for its protection from corrosion and the adsorption of inhibitor was shown by UV-vis. spectroscopic technique. Fourier Transform Infrared Spectroscopy technique confirmed the existence of functional groups and the heteroatoms exhibit in the inhibitor. Adsorbance by the inhibitory molecules on the carbon steel surface followed the Langmuir adsorption isotherm. Hypothetical investigations (computational) showed a very valuable report. All acquired outcomes ensure that M. charantia extract can procedure an effectual preventing layer and restrict the corrosion procedure.
  • Küçük Resim Yok
    Öğe
    Corrosion inhibition, surface adsorption and computational studies of Swertia chirata extract: A sustainable and green approach
    (Elsevier Science Sa, 2021) Haldhar, Rajesh; Prasad, Dwarika; Nguyen, Le T. D.; Kaya, Savas; Bahadur, Indra; Dagdag, Omar; Kim, Seong-Cheol
    The aerial parts extracted from Swertia chirata (S. chirata) plant were employed for the corrosion resistance of carbon steel in the acidic medium (0.5 M H2SO4) utilizing by weight-loss method, Tafel and EIS. The state of mixed inhibitor adsorption on the carbon steel surface were shown by potentiodynamic polarization. S. chirata achieved the extraordinary inhibition efficiency of 92.32% at 500 mg/L of inhibitor concentration. SEM and AFM were used to know about the thin layer formed on the surface of carbon steel for its protection from corrosion and the adsorption of inhibitors shown by UV-vis analysis FT-IR technique confirmed the existence of functional groups and the heteroatoms exhibited in the inhibitor. Adsorbance by the inhibitory molecules on the carbon steel surface followed the Langmuir adsorption isotherm. Theoretical investigations (computational) showed a precious report which was supported by experimental results. All acquired outcomes ensure that S. chirata extract can procedure an effectual preventing layer and restrict the corrosion procedure.
  • Küçük Resim Yok
    Öğe
    Investigation of plant waste as a renewable biomass source to develop efficient, economical and eco-friendly corrosion inhibitor
    (Elsevier, 2021) Haldhar, Rajesh; Prasad, Dwarika; Bahadur, Indra; Dagdag, Omar; Kaya, Savas; Verma, Dakeshwar Kumar; Kim, Seong-Cheol
    Various concentration of Solanum surattense (S. surattense) aerial parts extract was utilized for low carbon steel (LCS) in the presence of corrosive medium (0.5 M sulfuric acid) utilizing weight-loss technique and electrochemical methods (Tafel and EIS). The mixed adsorption status on the LCS was exhibited by potentiodynamic polarization. S. surattense accomplished 93% corrosion inhibition effectiveness at an inhibitor concentration of 500 mg/L. SEM and AFM was utilized to distinguish the thin film framed on the outside of the metal alloy to protect it from corrosion. The molecular adhesion of the inhibitor was demonstrated to be Ultraviolet-visible (UV-Vis) spectroscopic method. The FT-IR strategy supported the existence of different functional groups and different atoms other than Carbon and Nitrogen in the protective extract. Thin layer adhesion of the inhibitor molecules outside of LCS metal substrate obeyed the Langmuir adsorption isotherm and acted as mixed type inhibitor. DFT revealed an entirely important report with high EHOMO and low ELUMO values for active phytoconstituents showing potential nature of inhibitor and good agreements with experimental outcomes. The whole acquired results entail that S. surattense creates protective coat hence limit the degree of LCS degradation. (C) 2021 Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Natural corrosion inhibitors: Adsorption mechanism
    (De Gruyter, 2022) Dagdag, Omar; Haldhar, Rajesh; Kim, Seong-Cheol; Berdimurodov, Elyor; Ebenso, Eno E.; Kaya, Savas
    The motivation behind this chapter is to give an outline of the bibliographic insights expected to structure our segment. We examine modern green corrosion inhibitors and their restraint and adsorption systems. The corrosion repressing impacts of different plant extracts are additionally discussed utilizing weight loss (WL) and electrochemical techniques. Also, this chapter talks about surface investigation, including chemical examination. © 2022 Walter de Gruyter GmbH, Berlin/Boston. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Papaver somniferum as an efficient corrosion inhibitor for iron alloy in acidic condition: DFT, MC simulation, LCMS and electrochemical studies
    (Elsevier, 2021) Haldhar, Rajesh; Kim, Seong-Cheol; Prasad, Dwarika; Bedair, M. A.; Bahadur, Indra; Kaya, Savas; Dagdag, Omar
    The corrosion resistance of iron alloy in 0.5 M sulphuric acid was checked in the presence and absence of Papaver somniferum ( P. somniferum ) seed extract. Notably, P. somniferum showed 95% corrosion resistance efficiency at 500 mg/L concentration. The adsorption of this inhibitor follows the Langmuir isotherm indicating its monolayer formation on the surface of iron alloy. The potentiodynamic experiments indicated its nature as mixed type of inhibition behaviour. The SEM and AFM techniques were used to study the protective layer on iron alloy. FT-IR with ATR confirmed various functional groups containing heteroatoms present in phytochemicals and formed complex with iron respectively. Theoretical studies were given as a valuable report to understand the comparative adsorption of phytochemical. All acquired outcomes confirmed that P. somniferum seed extract act as an efficient corrosion inhibitor. (c) 2021 Elsevier B.V. All rights reserved.
  • Küçük Resim Yok
    Öğe
    Performance of curing epoxy resin as potential anticorrosive coating for carbon steel in 3.5% NaCl medium: Combining experimental and computational approaches
    (Elsevier, 2021) Hsissou, Rachid; Benhiba, Fouad; Echihi, Siham; Benzidia, Bouchra; Cherrouf, Sghir; Haldhar, Rajesh; Alvi, Parvez Ahmad
    Triglycidyl ether triethoxy triazine (TGETET) epoxy resin cured by 1.6-diaminohexane (TGETET/DAH) and 4.4diaminodiphenyl methane (TGETET/DDM) was investigated as potential anticorrosive coating for carbon steel in sodium chloride medium. Polarization curves (PC) and electrochemical impedance spectroscopy (EIS) results displayed the protective efficiency of TGETET/DDM is higher than that of TGETET/DAH in 3.5 %NaCl medium. SEM data showed that both TGETET/DAH and TGETET/DDM could be significantly stopped the chloride ions attack due to adhesion between the protective layer formed on CS coated. Chemical reactivity tendency of TGETET/DAH and TGETET/DDM compounds were evaluated using global quantum chemical descriptors (GQCDs) and molecular dynamics simulation (MDs).
  • Küçük Resim Yok
    Öğe
    Surface adsorption and corrosion resistance performance of modified chitosan: Gravimetric, electrochemical, and computational studies
    (Elsevier, 2024) Haldhar, Rajesh; Raorane, Chaitany Jayprakash; Mishra, V. K.; Tuzun, Burak; Berdimurodov, Elyor; Kim, Seong-Cheol
    Two novel chitosan derivatives (water soluble and acid soluble) modified with thiocarbohydrazide were produced by a quick and easy technique using formaldehyde as links. The novel compounds were synthesized and then characterized by thermogravimetric analysis, elemental analysis, nuclear magnetic resonance spectroscopy, Fourier transform infrared spectroscopy, and differential scanning calorimetry. Their surface morphologies were examined using scanning electron microscopy. These chitosan derivatives could produce pH-dependent gels. The behavior of mild steel in 5 % acetic acid, including both inhibitors at various concentrations, was investigated using gravimetric and electrochemical experiments. According to the early findings, both compounds (TCFACN and TCFWCN) functioned as mixed-type metal corrosion inhibitors. Both inhibitors showed their best corrosion inhibition efficiency at 80 mg L-1. TCFACN and TCFWCN, showed approximately 92 % and 94 % corrosion inhibition, respectively, at an optimal concentration of 80 mg L-1, according to electrochemical analysis. In the corrosion test, the water contact angle of the polished MS sample at 87.90 degrees C was reduced to 51 degrees C. The water contact angles for MS inhibited by TCFACN and TCFWCN in the same electrolyte were greater, measuring 78.10 degrees C and 93.10 degrees C, respectively. The theoretical results also support the experimental findings.