Removal of cationic pollutants from water by xanthated corn cob: optimization, kinetics, thermodynamics, and prediction of purification process

The removal of Cr(III) ions and methylene blue (MB) from aqueous solutions by xanthated corn cob (xCC) in batch conditions was investigated. The sorption capacity of xCC strongly depended of the pH, and increase when the pH rises. The kinetics was well fitted by pseudo-second order and Chrastil’s model. Sorption of Cr(III) ions and MB on xCC was rapid during the first 20 min of contact time and, thereafter, the biosorption rate decrease gradually until reaching equilibrium. The maximum sorption capacity of 17.13 and 83.89 mg g-1 for Cr(III) ions and MB, respectively was obtained at 40 °C, pH 5 and sorbent dose 4 g dm-3 for removal of Cr(III) ions and 1 g dm-3 for removal of MB. The prediction of purification process was successfully carried out and the verification of theoretically calculated amounts of sorbent was confirmed by using packed-bed column laboratory system with recirculation of the aqueous phase. The wastewater from chrome plating industry was successfully purified, i.e. after 40 min concentration of Cr(III) ions was decreased lower than 0.1 mg dm-3. Also, removal of MB from the river water was successfully carried out and after 40 min removal efficiency was about 94 %

1,2-bis(4-chlorobenzylidene)Azine as new and effective corrosion inhibitor for copper in 0.1 N HCl A combined experimental and theoretical approach

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Evaluation of the effect of Tetramethylammonium hydroxide on the corrosion inhibition of A9M steel in industrial water an experimental, morphological and MD simulation insights.

International audienceCorrosion inhibition performance of Tetramethylammonium hydroxide (TMAH), for A9M steel in industrial water (IW) was investigated using weight loss, potentiodynamic polarization and EIS measurement. The results showed that the inhibition efficiency of the TMAH increases with the increase of its concentration which acts as anodic inhibitor. The Characterizations that have been performed as the surface morphology by optical microscope, surface roughness and scanning electron microscopy (SEM) have proved that TMAH can exhibit good inhibition ability by forming a protective film on A9M steel surface. Molecular dynamics simulation were used to investigate the strength of the interactions between metal surface and the tested compound. The data obtained from theoretical and experimental studies were in reasonable agreement

Enhanced corrosion inhibition of carbon steel in HCl solution by a newly synthesized hydrazone derivative: Mechanism exploration from electrochemical, XPS, and computational studies

International audienceThe corrosion inhibition properties of a synthesized hydrazone derivative namely, 1-(4-isopropyl phenyl) -2- (2,4-dinitrophenyl) (HYD (iso)) on API 5L-X60 carbon steel (CS) in 1.0 M HCl solution were evaluated by chemical, electrochemical, X-ray photoelectron spectroscopy (XPS) and theoretical studies. The obtained results revealed that the tested compound acted as a good corrosion inhibitor with inhibition efficiency of 96.32% at a concentration of 5 × 10−3 M. The polarization technique indicated that the HYD (iso) belonged to mixed-type inhibitors, preventing simultaneously anodic and cathodic reactions. The binding between the HYD (iso)'s molecule and CS surface follows a Langmuir adsorption type model and its inhibition mechanism is assisted by physical and chemical interactions. Scanning electron microscope (SEM) and contact angle analyses were performed to examine the surface morphology of inhibited and uninhibited samples. Additionally, theoretical studies using Density Functional Theory (DFT) and molecular dynamics (MD) simulation were performed to explore the most reactive sites of the hydrazone molecule and its adsorption mechanism

Hydrazone-based green corrosion inhibitors for API grade carbon steel in HCl: Insights from electrochemical, XPS, and computational studies

International audienceCorrosion protection of carbon steel (CS) is an important challenge in the industry field. The search for an effective protection approach is still a hot research question. In the present work, three hydrazone derivatives (HZ-OH, HZ-Me, and HZ-Cl) were used in 1.0 M HCl solution for API grade CS corrosion mitigation. Their corrosion inhibition performance was evaluated by electrochemical tests while steel surface was analyzed by X-ray photoelectron spectroscopy (XPS), contact angle and scanning electron microscope (SEM). Electrochemical tests showed an inhibition efficiency between 91% and 98% for CS exposed to acidic solution containing 0.05 mol/L of the three hydrazone derivatives. All compounds were classified as mixed type inhibitors, inhibiting both cathodic and anodic corrosion reactions. XPS showed that inhibitor molecules formed a stable layer on steel surface through chemical and physical interactions. The adsorption of molecules onto the steel surface was found to follow Langmuir model. DFT and MD simulations were used to investigate the interaction of hydrazones with Fen (n = 1–4) and Fe2O3(001) surface, respectively. They confirmed that the inhibitor with two hydroxy groups (HZ-OH) had a greater interaction with iron atoms. © 2021 Elsevier B.V