A new photochemical route is disclosed in the preparation of a wide range of benzimidazoles in air under the illumination of an HP mercury lamp in the absence of any oxidizing species catalyzed by heterogenized W–ZnO@NH2–CBB.

WO3/ZnO@NH2-EY is disclosed in the preparation of chromenes under air in the presence of a green LED. ˙O2−, OH˙, and h+ are proposed as reactive species and hot filtration test assured stability and reusability of the nanocatalyst.

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Ammonium constitutes a hampering element in the production of drinking water. It interferes with the chlorination to form chloramines so modifying the smell and the taste of the water. This paper presents the description and the optimization operations of the biggest biological treatment plant in Morocco for the elimination of ammonium in the presence of sulphides. The difficulties met and the steps taken to surmount them are described. These steps greatly improved performance but did not reach the planned and the contractual requirements. The paper also presents the preliminary results of ammonium removal by an electrodialysis pilot plant. The ED tests showed excellent performance and the water quality was significantly improved, especially the TDS.

In this study, a composite of zinc tungsten oxide nanoparticles (W-ZnO NPs) has been synthesized via mixing Na2WO4 and zinc acetate in water, followed by dropwise addition of NaOH. The synthesized W-ZnO NPs were characterized using measurement methods such as XRD, dynamic light scattering (DLS), Scanning electron microscopy (SEM) and UV-Vis. Also, the results were compared with the pure synthesized ZnO and WO3 NPs. Non-linear optical properties of the synthesized composite were measured using the Z-scan technique with a continuous wave Nd-Yag laser. The negative non-linear absorption coefficient of the components was obtained which indicates that the saturation absorption occurred in this composite. In comparison with pure ZnO NPs, non-linear absorption decreases which can be attributed to the negligible optical response of WO3 structures. Also, the negative value of the close aperture Z-scan curve shows that the thermal lensing effect is the main reason for the third-order non-linear refraction.

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