The assessment of photocatalytic activity of zinc oxide nanoparticles from the roots of Codonopsis lanceolata synthesized by one-pot green synthesis method

Abstract

Codonopsis lanceolata is a perennial herb called as ‘Doedok’ in Korea. The roots of C. lanceolata has been reported to have antioxidant and antimicrobial properties. The chemically reactive saponins of C. lanceolata might be used as a capping agent for the surface of ZnO nanoparticle, ultimately making it an efficient photocatalyst. This paper, reports the one-pot green synthesis of ZnO nanoparticles via Co- precipitation method using root extract of C. lanceolata. The structure of green synthesized Cl-ZnO NPs was characterized using X-ray Powder Diffraction (XRD), Elemental Distribution (EDX) and morphology using Field Emission Transmission Electron Microscopy (FE-TEM). The Fourier-transform infrared spectroscopy (FT-IR) exhibited the information about the functional groups that capped the metal nanoparticle. The formation of metal NPs was confirmed by UV–vis spectra absorbance at 356 nm. The Cl-ZnO NPs were evaluated for their catalytic activity by measuring the degradation of methylene blue (MB) dye in aqueous solution under UV light (365 nm). The result showed efficient degradation of methylene blue, which was degraded 90.3% within 40 min by Cl-ZnO NPs while the photo-degradation reaction rate constant K was found to be 0.057. In brief, the phytochemicals present in C. lanceolata extract are potential reducing agent to produce Cl-ZnO nanoparticles. The Cl-ZnO NPs are proficient to degrade Methylene Blue in short time with high photocatalysis rate due to the extract capped zinc-oxide nanoparticles. Therefore, the use of C. lanceolata for the biosynthesis of nanoparticles may have vast applications as a cost- effective and eco-friendly photocatalyst.