Silver nanoparticles mediated by extract of Guar plant (Cyamopsis tetragonoloba), and evaluation of their photocatalytic and antibacterial properties

 Elias E. Elemike^1,2,3 , Saiyed Tanzim^1,2, Anthony C. Ekennia⁴, Damian C. Onwudiwe^1,2*

¹Material Science Innovation and Modelling (MaSIM) Research Focus Area, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.

²Department of Chemistry, School of Physical and Chemical Sciences, Faculty of Natural and Agricultural Sciences, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa.

³Department of Chemistry, College of Science, Federal University of Petroleum Resources,  P.M.B 1221, Effurun, Delta State, Nigeria.

⁴Department of Chemistry, Alex Ekwueme Federal University Ndufu-Alike, PMB 1010, Abakaliki, Ebonyi State, Nigeria

DOI: 10.5185/amlett.2018.2198

Publication Date (Web): Oct 26, 2018

Copyright © 2018 VBRI Press

E-mail: Damian.Onwudiwe@nwu.ac.za

Abstract

The green synthesis of silver nanoparticles using Cyamopsis tetragonoloba plant extract, and their photocatalytic and antibacterial properties is reported. Three precursor concentrations of 1 mM, 2 mM and 5 mM were used, and at two different ratios of 1:5 and 1:10 plant extract to the precursor. The formation of the nanoparticles was followed by the periodic study of surface plasmon resonance using the UV-visible spectroscopy, which revealed the formation of nanoparticles with regular bands after 45 min. of reaction. Fourier transform infrared spectroscopy was used to study the functional groups present in the plant biomolecules which aided the reduction and stabilization of the nanoparticles. Transmission electron microscopy analysis and X-ray diffraction pattern showed the particle sizes and crystalline structures, while the zeta potential values indicated the stability of the nanoparticles. The 5 mM concentration gave the largest particle sizes of about 12.90 nm and the most stable particles. The photocatalytic properties of the particles studied using Methyl red showed a low efficiency of 17.85% degradation achieved under 2 h. The antibacterial potency of the nanoparticles was screened against some gram-negative and gram-positive bacteria. The results showed that the nanoparticles have good antibacterial activities.

Keywords

Silver nanoparticles, green synthesis, photocatalysis, antibacterial