Abstract
A new preparation method has been successfully utilized for the fabrication of zinc oxide nanoparticles using the auto-combustion method and fuels (tartaric acid: TA and citric acid: CA) with molar ratio (Zn:TA:CA=1:1:0, 1:0:0.55 and 1:0.5:0.275). The as-fabricated ZTA, ZCA and ZCTA samples annealed at 500 oC for two hours. The calcined zinc oxide nanoparticles were investigated by various tools such as XRD, DRS, FT-IR, and HR-TEM. The average crystallite size of the fabricated zinc oxide was determined to be 24-39 nm. The direct band gap, lattice parameters, unit cell volume (V), the dislocation density (D) and the Zn-O bond length (L) of the synthesized ZTA, ZCA and ZCTA samples were determined. The synthesized zinc oxide nanoparticles are used as nanocatalyst for photodegradation of reactive red 195 and methyl orange dyes under UV light irradiation. The degradation of reactive red 195 dye was 91-94 % after 70 min over the synthesized zinc oxide and the values of degradation increased to be 99-99.8 % in 50 min with H2O2 under UV light irradiation. Also, the degradation of methyl orange dye was 57.55-70.57 % after 300 min over the synthesized zinc oxide (ZTA, ZCA and ZCTA samples) and the values of degradation increased to be 81-95 % in 70 min with H2O2 under UV light irradiation. Finally, the appeared rate constant (Kapp) is determined and the mechanism of the photocatalysis process is suggested for the degradation of the dyes over the synthesized zinc oxide nanoparticles.
Preparation of highly active zinc oxide for photocatalytic removal of phenol: Direct calcination versus co-precipitation method