ZnO thin film was synthesized by sol-gel method and dip-coated on granular porous natural scoria. CuO nanoparticles were synthesized on ZnO/scoria using a direct crystallization approach in the presence of sodium borohydride. Structure and characterization of ZnO/scoria and CuO/ZnO/scoria nanophotocatalysts were studied by X-ray diffraction (XRD) analysis, energy-dispersive X-ray spectroscopy (EDS), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). Photocatalytic decolorization of acid blue 113 and a textile wastewater were performed using the CuO/ZnO/scoria nanophotocatalyst under LED visible lamps in a continuous open channel reactor. Effect of pH, flow rate, initial dye concentration and coexisting anions were investigated. The higher acid blue 113 decolorization efficiency was obtained equal to 62.45% at pH=5, initial dye concentration of 20 mgL -1 and flow rate of 15 ml min -1 . For a textile wastewater with initial chemical oxygen demand (COD) of 700 mg L -1 , 72% COD removal was obtained at pH= 4 and flow rate of 2 ml min -1 .
Experimental
MaterialsGranular scoria was obtained from Qorveh mine in Kordestan, west of Iran. AB113 was purchased from Sabet Alvand Company, Hamedan, Iran. Zink acetate dihydrate, oxalic acid, ethanol, CuSO 4 , HNO 3 , NaNO 3 , NaOH, H 2 SO 4 , K 2 Cr 2 O 7 , HgSO 4 , Ag 2 SO 4 , and HCl all were obtained from Merck Company in analytical grade. The textile wastewater containing AB113 with blue color, pH 4.8 ± 0.2, conductivity 3.59 mS cm -1 , and chemical oxygen demand (COD) 700 mg L -1 was obtained from Farsh & Patu factory in Tabriz, Iran.
Measurement of AB113An AB113 aqueous solution (20 mg L -1 ) was used to plot its absorbance versus wave length in the range of 200-800 nm and 566 nm was found as the maximum absorbance wavelength. At this wave length the absorbance values of different known solutions of