Characterization and application of natural Moroccan material for methyl violet 2B dye removal from aqueous solution.

In this paper, a natural Moroccan material from the Nador area in the north east of Morocco was studied as an adsorbent to remove methyl violet 2B dye from aqueous solutions. This material has never been studied before in this region, and it will be used in its raw state. It was collected and characterized by X-ray diffraction, FTIR spectroscopy, scanning electron microscopy, X-ray fluorescence, thermal analysis, N2 gas adsorption-desorption, pHPZC, and Brunauer-Emmett-Teller (BET). The studies are realized with a 500-µm grain size and 182m2/g BET surface area. XRD showed the presence of significant peaks belonging to natural zeolite type clinoptilolite-Ca and minor phases. Several parameters were studied such as contact time, adsorbent mass, initial dye concentration, initial pH solution, the particle size of the material, and temperature. Out of the three isotherm models investigated after 60 min of contact time in the experiments, the Langmuir model gave the best fit to the experimental data (R2 = 0.99). The results of kinetic and thermodynamic studies revealed that the adsorption process obeyed pseudo-second-order, spontaneous (ΔG° < 0), endothermic (ΔS° > 0). The adsorption of methyl violet 2B dye is chemisorptions and physisorption. The maximum theoretical adsorption capacity was 30.30 mg·g-1 at 23 °C for a particle diameter of 500 µm. The desorption study shows that the material can be desorbed using solvents. The reuse study indicates that the same amount of natural zeolite can be used several times which makes the process efficient and sustainable. The obtained results indicate that the country of Morocco has natural zeolite among its resources and that it can be used as an efficient adsorbent for the removal of dyes.

Performance Evaluation of New Chalcone Oxime Functionalized Graphene Oxide as a Corrosion Inhibitor for Carbon Steel in a Hydrochloric Acid Solution.

This study aims to synthesize new chalcone oxime functionalized graphene oxide (CO-GO) and investigate the enhancement in corrosion protection. The morphology and structure of the synthesized CO-GO have been characterized by elemental analysis: Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), thermal gravimetric analysis (TGA), and scanning electron microscopy (SEM). Moreover, the effectiveness of corrosion inhibition was investigated by utilizing electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The results of the above analyses demonstrate that CO-GO has an outstanding corrosion inhibitor performance of up to 94% and acts as a mixed-type inhibitor with a primarily anodic action. The effect of temperature on a carbon steel surface indicates that the tested composites are chemisorbed. A few techniques were able to provide surface characterization such as scanning electron microscopy and ultraviolet (UV)-visible spectroscopy to confirm inhibitor adsorption on the carbon steel surface.

Elaboration of Lamellar and Nanostructured Materials Based on Manganese: Efficient Adsorbents for Removing Heavy Metals.

The lamellar and nanostructured manganese oxide materials were chemically synthesized by soft and non-toxic methods. The materials showed a monophasic character, symptomatic morphologies, as well as the predominance of a mesoporous structure. The removal of heavy metals Cd(II) and Pb(II) by the synthesized materials Na-MnO2, Urchin-MnO2 and Cocoon-MnO2 according to the mineral structure and nature of the sites were also studied. Kinetically, the lamellar manganese oxide material Na-MnO2 was the most efficient of the three materials which had more vacancies in the MnO6 layers as well as in the space between the layers. The nanomaterials Urchin-MnO2 and Cocoon-MnO2 could exchange with the metal cations in their tunnels and cavities, respectively. The maximum adsorbed quantities followed the order (Pb(II): Na-MnO2 (297 mg/g)?Urchin-MnO2 (264 mg/g)?Cocoon-MnO2 (209 mg/g), Cd(II): Na-MnO2 (199 mg/g)?Urchin-MnO2 (191 mg/g)?Cocoon-MnO2 (172 mg/g)). Na-MnO2 material exhibited the best stability among the different structures, Na-MnO2 presented a very low amount of the manganese released. The results obtained showed the potential of lamellar manganese oxides (Na-MnO2) and nanostructures (Urchin-MnO2 and Cocoon-MnO2) as selective, economical, and stable materials for the removal of toxic metals in an aqueous medium.