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Efficient cleaning of contaminated water by photocatalysis has become an effective strategy in recent years due to its environmental and ecological designation. The cadmium sulfate (CdS) ) is an excellent photocatalyst in the visible region but has low quantum efficiency. In order to increase the photocataletic efficiency, CdS was modified with gadolinium oxide (Gd2O3) and combined with graphene oxide (GO) nanoparticles. The estimated crystallite size (Ds) for Gd2O3, CdS/Gd2O3 and CdS/Gd2O3@GO was 29.6, 11.6 and 11.5 nm, respectively. The degradation of methylene blue (MB) reaches the highest values after (60 min) under visible light irradiation with a dye concentration of (0.25 ppm). Whereas in powdered composition the efficiency of dye removal has been enhanced under UV irradiation, while it reduced by increasing the MB concentration to 0.50 ppm with visible light irradiation. In addition, the CdS with/without Gd2O3 and GO were integrated into electrospun nanofibrous cellulose acetate (CA) through the electrospinning technique. The compounds of Gd2O3, CdS/Gd2O3 and CdS/Gd2O3/GO were encapsulated into cellulose acetate (CA) nanofibers, for the degradation of MB under visible and UV irradiation. The apparent rate constant (k) achieves a value of 0.006, 0.007 and 0.0013 min− 1 while, the removal efficiency reaches 41.02%, 54.71%, and 71.42% for Gd2O3@CA, CdS/Gd2O3@CA, CdS/Gd2O3/GO@CA respectively after 60 min under UV irradiation.

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Molybdenum plasma in air at atmospheric pressure was carried out by utilizing Nd-YAG laser at fundamental wavelength 1064 nm, 0.206 mJ input energy, 5 ns pulse duration and repetition rate 10 Hz. After plasma formation, the optical fiber was used to collect plasma emission. The spectral analysis was displayed in the Local Thermal Equilibrium (LTE) state. Electron temperature was estimated by Boltzmann plot method and electron density was calculated from Stark broadening and compared with electron density of Hα-line at 656.3 nm which has reliable values. The temperature of plasma and density were evaluated for different positions along the expansion axis. The influence of the input power on plasma was studied. The electron density varied from 5 ×10 18 to 3.5×10 19 cm -3 . These parameters are important in environmental and industrial application. At distance of 10 mm from the target, the electron temperature has a minimum value while the electron density shows a maximum value.