UNE TYPOLOGIE POUR LES QUARTIERS INFORMELS A BISKRA

Au milieu d’une crise économique contraignante ayant provoqué une hausse vertigineuse des prix de terrain à bâtir, de matériaux de construction et même de main d’oeuvre, le logement en Algérie devient aujourd’hui inaccessible y compris pour les couches moyennes. La faiblesse des réalisations du logement social urbain, la rapide croissance démographique et l’exode rural massif ont favorisé la naissance et la prolifération de l’habitat informel. La ville de Biskra n’a pas échappé à ce fléau. Cet article tente une approche typologique des quartiers démunis pour une meilleure compréhension des mécanismes de leur évolution et de la manière de les aborder en vue d’améliorer les conditions de vie de leurs habitants

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

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