Chemical Synthesis of Zinc Oxide Nanoparticles and Its Application of Dye Decolourization

Document Type: Research Paper


Department of Chemical Engineering, Faculty of Engineering and Technology, Annamalai University, P. O. Box 608002, Cuddalore, India.


   In the present study, various size of Zinc Oxide Nanoparticles (ZnO NPs) was synthesized via Sol-gel method. The photocatalytic activity of the synthesized ZnO NPs was investigated for the Decolourization of three different colored dyes viz. Congo Red, Acid Blue 9 and Coomassie Brilliant Blue R-250 under UV lamp. Zinc Chloride (Zncl2) and Sodium Hydroxide (NaOH) were used for the chemical synthesis. The SEM and FTIR analysis shows that the synthesized ZnO NPs are crystalline in nature. The synthesized NPs were then checked for its efficiency to decolorize the above same dyes under the condition of 20 mg/L dye and 0.3 g/L of photocatalyst dosage. The investigation results showed that each size of ZnO NPs was able to effectively decolorize the dye solution and the efficiency was found to be 88% for Congo red (CR: 27-29 nm), 73% for Acid Blue 9 (AB: 24-27 nm) and 70% for Coomassie Brilliant Blue R-250 (BB: 29-32 nm). Out of which CR dye oxidation rate was higher than the other dyes and especially BB dye possible to decolorize by using synthesized ZnO NPs.  Hence, it was concluded that ZnO NPs by itself is strong enough to decolorize these dye aqueous solutions. Moreover, the photocatalytic activity of NPs on dye was the decisive factor/unique property for dye reduction rather than size and morphology of the ZnO NPs.