Abstract: A new nanocomposite namely gold nanoparticles doped cadmium selenium doped tungsten trioxide (Au/CdSe/WO3) photocatalyst was produced under laboratory conditions to photodegrade the toxaphene and tetradifon insecticides from a chemical industry wastewaters producing insecticides. The XRD pathways of WO3 exhibited that it displays a number of peaks at 2θ = 25.09o, 24.63o, 25.60o, 27.09o, 29.09o, 34.011o, 35.99o, 42.86o, 53.40o. FTIR results showed that the band at 976 cm−1 signifies the W = O stretching vibration whereas the band appearing at 1396 cm−1 corroborated to the O–H bending vibration in W–OH. TEM data showed that Au/CdSe/WO3 nanocomposite consisting of Au, CdSe and WO3. Bare WO3 exhibited irregular/non-spherical nano-beads while the CdSe has sheets in huge density with packed sheets . The surface plasmon resonance (SPR) peak at around 590 nm confirms the transformation of Au/CdSe/WO3 nanomaterials to plasmonic Au/CdSe/WO3 nanocomposite. The XPS peak at 288.12 eV signifies the existence of oxygenated functional groups such as C-O, C O, or COOH within nanocomposite, resulting from oxidation of carbon. The bandgap values of nanocomposite calculated with Kubelka-Munk function are 3.05 eV, 3.15 eV and 3.16 eV at 500°C, 650°C and 800°C temperatures,respectively. For maximum toxaphene (99%) and tetradifon (97%) photodegradation yields the optimized operational conditions were as follows: 800 mg/l insecticide concentration, 20oC temperature, 1 mg/l Au/CdSe/WO3 nanocomposite dose, pH=8.0, 10 min retention time and a light power of 20 W/m2. The reusability of the Au/CdSe/WO3 nanocomposite was performed during 80 cycles. From the 1st to the 79th cycle, the photodegradation efficiencies for both toxaphene and tetradifon were consistently recorded as 99%.

Keywords: Chemical industry wastewater, Gold doped cadmium selenide doped tungstene trioxide (Au/CdSe/WO3), Insecticide, Kubelka-Munk function, Nanocomposite, Nanoparticle, Photocatalyst, Photodegradation, Tetradifon, Toxaphene

Pages: 10-49

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