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In this study, triphenylaniline-based porous organic polymers (TPA-POPs) were successfully prepared by the Friedel–Crafts reaction and applied to adsorb malachite green (MG) dye from water. The TPA-POP was characterized using TEM, SEM, FTIR, 13C (CP/MAS) NMR, BET surface area, and XRD analysis. The results exhibited that the TPA-POP has a high surface area (1625.14 m2/g) with pore volume (0.353 cm3/g) and pore radius (1.57 nm) that reflect the high quantity of MG adsorbed on the TPA-POP. The polymer was evaluated as an excellent adsorbent for MG adsorption from water using the batch method. MG dye removal was optimized as 99.60% (at pH: 6.0, adsorbent dosage (m): 0.01 g, temperature (T): 45 °C, and contact time (t): 300 min). The kinetic data follow the Elovich model, while the isotherm data fit the Langmuir model well with uptake capacity (755.72 mg/g) at T: 45 °C. According to thermodynamic parameters, the adsorption process was endothermic and spontaneous. The adsorption of MG on the TPA-POP occurred via different mechanisms (π–π interaction, electrostatic attraction, and hydrogen bonding). Reusability experiments exhibited that the TPA-POP still maintained high removal efficiency (82.12%) after five cycles. In conclusion, the TPA-POP is a promising adsorbent owing to its cost-effectiveness, high adsorption capacity, high surface area, excellent reusability, and efficient MG removal from aqueous media. [ABSTRACT FROM AUTHOR]

A new nonionic surfactant (NIS), namely, 17-hydroxy-3,6,9,12,15-pentaoxaheptadecyl-5- ((4-(((17-hydroxy-3,6,9,12,15-penta oxa hepta decyl) oxy) sulfonyl) phenyl) diazenyl)-2-(2-oxo-2H- chromene-3-carboxamido) benzene sulfonate was synthesized based on condensation reaction between an azo dye and polyethylene glycol. The chemical structure was elucidated from IR and 1H NMR spectral data and surface activity was measured. The inhibitive effect of the resultant NIS toward corrosion of steel in 1.0 M HCl was evaluated by potentiodynamic polarization, impedance spectroscopy (EIS), non-electrochemical methods (weight loss), surface morphology (SEM and EDX) and DFT calculations. The anti-corrosion performance showed an optimal efficiency of 96.04% at the concentration of 7.50 × 10−4 M from polarization measurements. Both the anodic and cathodic inhibition were acquired from Tafel plots polarizations (TFP). The adsorption of NIS onto steel surface obeyed Langmuir isotherm. In addition, SEM images showed higher surface protection in presence of inhibitor in agreement with a molecular dynamic simulation which exhibited optimal surface alignment between inhibitor and steel. A good agreement between electrochemical methods and DFT calculations was achieved. [ABSTRACT FROM AUTHOR]

Tetraethyl orthosilicate (TEOS) was used as a chemical precursor to deposit ultra-thin SiOxCy plasma polymer films onto mild steel surfaces for preventing the corrosion process. The structure--property relationships of the coatings were evaluated by X-ray Photo Spectroscopy (XPS), X-Ray Diffraction (XRD), Fourier Transform InfraRed spectroscopy (ATR-FTIR) and Energy Dispersive X-ray spectroscopy (EDX) completed with Scanning Electron Microscopy (SEM). The SEM micrographs confirmed a pinhole-free surface morphology of the low-pressure deposited plasma polymer films. The TEOS molecules become fragmented in the plasma by numerous collisions with energy-rich electrons and heavier particles. Recombination of fragments and condensation onto the steel substrate is responsible for the formation of organic SiO containing plasma polymer layers. Such thin layers consist of predominantly SiOx structures. Their properties are determined largely by the gap distance between the two samples used as electrodes in the plasma. The efficiency of the corrosion-protecting coating was compared with uncoated samples. The corrosion protection was determined by exposure of samples to 3.5% NaCl aqueous solutions. For this purpose, polarization and Electrochemical Impedance Spectroscopy (EIS) were used to monitor the corrosion. The optimal gap distance between the electrodes was determined for corrosion protection. The best protective efficiency reached more than 97% of the total protection as measured at room temperature. [ABSTRACT FROM AUTHOR]

The inhibition process of steel against corrosion in 1.0 M HCl using natural honey in the presence and absence of 0.1 M KI was studied at 25–55 °C utilizing a potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements and gravimetric method. Corresponding surfaces of steel were examined by SEM and EDX techniques. The obtained data demonstrated that inhibition efficiency increased by increasing both natural honey dose and environment temperature. Synergism parameter values were found more than one indicating that the inhibition efficiency of natural honey enhanced by an addition of KI due to synergism. The adsorption of natural honey in the presence and absence of iodide ions on the steel surface was found to follow Langmuir adsorption isotherm. [ABSTRACT FROM AUTHOR]

Two organo-silicon compounds namely; di-triethanolamine siloxane and bis (dithioamine triethanolamine) siloxane were employed as inhibitors for C-steel alloys corrosion in 1 M H2SO4 solution utilizing potentiodynamic polarization, electrochemical impedance and computational studies. According to both polarization and impedance data, it has been found that the investigated organo-silicon compounds work as efficient corrosion inhibitors and the protection aptitude raised by increasing the inhibitor concentration. The shown behavior of the tested compounds is cathodic and anodic type inhibition following Langmuir's adsorption isotherm. The evaluated adsorption parameters, adsorption equilibrium constant (Kads) and Gibbs free energy of adsorption (Δ G ads o) $(\Delta G_{{\rm{ads}}}^o)$ reveal a good association between the inhibitor molecules and the surface of carbon steel in a predominantly chemisorptions manner. In the view of computational quantum and molecular dynamic simulation studies, molecular structure effectiveness and suggested mechanism of protection efficiency were discussed. Surface characterization studies such as scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and X-ray diffraction (XRD) have been utilized as corroborative tools for confirming the presence of the defensive inhibitor film on the surface of a metal. [ABSTRACT FROM AUTHOR]

Two azo derivatives, 4-((4-hydroxy-3-((4-oxo-2-thioxothiazolidin-5-ylidene)methyl)phenyl) diazinyl) benzenesulfonic acid (TODB) and 4-((3-((4,4-dimethyl-2,6-dioxocyclohexylidene) methyl)-4-hydroxyphenyl)diazinyl) benzenesulfonic acid (DODB) were synthesized and characterized using Fourier-transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance ( 1 H-NMR) and mass spectral studies. Gravimetric methods, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), electrochemical frequency modulation (EFM) techniques and inductive coupled plasma-optical emission spectroscopy were used to verify the above two compounds' ability to operate as mild steel (MS) corrosion inhibitors in 1 M HCl. Tafel data suggest that TODB and DODB have mixed-type characteristics, and EIS findings demonstrate that increasing their concentration not only alters the charge transfer ( R ct ) of mild steel from 6.88 Ω cm 2 to 112.9 Ω cm 2 but also changes the capacitance of the adsorbed double layer ( C dl M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate.-2 . At 7.5 × 10 -4 M concentration, the azo derivatives showed the highest corrosion inhibition of 94.9% and 93.6%. The inhibitory molecule adsorption on the metal substrate followed the Langmuir isotherm. The thermodynamic activation functions of the dissolution process were also calculated as a function of inhibitor concentration. UV-vis, scanning electron microscopy (SEM), and energy dispersive X-ray spectroscopy (EDX) techniques were used to confirm the adsorption phenomenon. The quantum chemical parameters, inductively coupled plasma atomic emission spectroscopy (ICPE) measurements, and the anti-bacterial effect of these new derivatives against sulfate-reducing bacteria (SRB) were also investigated. Taken together, the acquired results demonstrate that these compounds can create an appropriate preventing surface and regulate the corrosion rate., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

In this research paper, aromatic sulfonamide-derived ethyl ester ( p -TSAE) and its acyl hydrazide ( p -TSAH) were directly synthesized, characterized, and employed for the first time as prospective anticorrosive agents to protect mild steel in 1.0 M HCl conditions. The corrosion efficiency was probed by electrochemical methods including polarization, impedance, and frequency modulation measurements. Optimal efficiencies of 94% and 92% were detected for the hydrazide and ester, respectively, revealing excellent corrosion inhibition. Moreover, both the hydrazide and ester molecules combat the cathodic and anodic reactions correspondingly in a mixed-type manner. The electron transfer (ET) at the inhibitor/metal interface was evaluated using DFT at the B3LYP/6-31g(d,p) level. Natural bond orbital analysis (NBO) and frontier molecular orbital analysis (FMO) calculations showed superior capabilities of the synthesized inhibitors to easily reallocate charge into the metal surface. However, the hydrazide molecules showed slightly better inhibition efficiency than the ester due to the strong interaction between the lone pairs of the nitrogen atoms and the d-orbitals of the metal. The chemical hardness of the hydrazide and ester are 2.507 and 2.511 eV, respectively, in good accordance with the recorded electrochemical inhibition efficiencies for both molecules. Good and straightforward correlations between the experiments and calculations are obtained., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)

The turbine blades of turbochargers are corroded after being cleaned with water in the presence of gasses produced during the combustion of heavy fuel. For that, manganese oxide (MnO 2 ), titanium dioxide (TiO 2 ), and titanium oxide-graphene (TiO 2 -C) nanomaterials have been coated on the nickel alloy, which is the composition of turbine blades, by the electrophoretic deposition technique for protection against the corrosion process. The anticorrosion performance of nanomaterial coatings has been investigated using electrochemical methods such as open circuit potential, potentiodynamic, electrochemical impedance, and linear polarization resistance in a 1 M H 2 SO 4 solution saturated with carbon dioxide. The corrosion rate of nanomaterial-coated Ni-alloy was lower than bare alloy, and potential corrosion increased from -0.486 V for uncoated Ni-alloy to -0.252 V versus saturated calomel electrode for nanomaterial coated Ni-alloy electrodes. Electrochemical measurements show that TiO 2 coated Ni-alloy corrosion has good protective qualities, with an efficiency of 99.91% at 0.146 mA cm 2 current density in sulfuric acid media. The findings of this study clearly show that TiO 2 has a high potential to prevent nickel alloy turbine blades from corrosion in acidic media. Furthermore, the surface morphologies have revealed that TiO 2 and MnO 2 coatings might successfully block an acid assault due to the high adhesion of the protective layer on the nickel alloy surface. The use of X-ray diffraction (XRD) enhanced the various measures used to determine and study the composition of the alloy surface's protective coating., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (This journal is © The Royal Society of Chemistry.)