CuO as efficient photo catalyst for photocatalytic decoloration of wastewater containing Azo dyes

Abstract

Cupric oxide nanoparticles (CuO NPs) were prepared via a chemical precipitation method using the precursor of copper (II) nitrate trihydrate. X-ray diffraction analysis confirms that the CuO NPs were a monoclinic crystal structure. The energy band gap of CuO NPs was found to be about 1.76 eV. The obtained CuO NPs were used as a photo catalyst to decolorize various dyes, such as methylene blue (MB), acid yellow 23 (AY 23) and reactive black 5 (RB 5), with a low concentration in the presence of visible light. The results show that the highest decolorization achieved was 67.8% and 66.3% for RB-5 dye and AY-23 dye, while 43.5% for MB dye from aqueous solution at 5 h illumination. The obtained CuO NPs were used as a photo catalyst to decolorize various dyes, RB-5, AY-23 and MB dye obeys pseudo first order kinetics with values of −0.112, −0.174 and −0.201 h−1, respectively. HIGHLIGHTS Chemically prepared Cupric oxide nanoparticles (CuO NPs) were used as efficient photo catalyst for degrading Azo dyes.; The energy band gap of CuO NPs was found to be about 1.76 eV.; Azo dyes like RB-5, AY-23 and MB obey pseudo first order kinetics.; The photocatalysis results show that the highest degradation achieved was 67.8% and 66.3% for RB-5 dye and AY-23 dye, while 43.5% for MB dye from aqueous solution at 5 h illumination.; The enhanced photo catalytic degradation of Azo dye can be explained in terms of ion charge and molecular weight.; Evaluation of photocatalytic degradation of RB5 and MB with reported literature data.;

Keywords

• acid yellow 23
• cuo nps
• methylene blue
• molecular weight
• photo decolorization
• reactive black 5