Dual action of both green and chemically synthesized zinc oxide nanoparticles: antibacterial activity and removal of Congo red dye
Mohamed A. Hassaan, Shimaa Hosny, Marwa R. Elkatory, Rehab M. Ali, Tauseef Ahmad Rangreez, Ahmed El Nemr
Abstract
ABSTRACT Two routes green and chemical were used to synthesize zinc oxide nanoparticles (ZnO NPs). Gelidium pulchellum extract was used as a bioreducing agent in this work. The formation of ZnO NPs was evaluated by Fourier transform infrared analysis with signals at 441 and 428 cm −1 for green and chemically synthesized ZnO NPs, respectively. ZnO NPs exhibiting hexagonal and cubic mixed phases were observed from the transmission electron microscopy and X-ray diffraction analysis with an average particle size of 17 nm for green and 22 nm for chemical. ZnO NPs showed a considerable antibacterial activity towards gram-positive bacteria Staphylococcus aureus, Bacillus subtilis, and Enterococcus faecalis than toward the gram-negative one. The outcomes of this study revealed the maximum inhibition zone for gram-positive bacteria growth (B. subtilis) was (27.3 ± 2.5 mm) by green ZnO NPs with the concentration of 100%. While the minimum inhibition zone was (11.3 ± 0.57 mm) represented by gram-positive bacteria (S. aureus) by chemically synthesized ZnO NPs with the concentration of 10%. So the antibacterial influences of ZnO NPs might be related to the characteristics of definite bacterial species, the size of the nanoparticles, and the synthesis methods (physical, chemical, or biological). Decolorization of Congo red (CR) dye was 85% after the first 3 min of the contact time with ZnO NPs.