Copyright © 2018 Authors. This is an open access article distributed under the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. International Journal of Engineering & Technology, 7 (4.14) (2018) 488-492 International Journal of Engineering & Technology Website: www.sciencepubco.com/index.php/IJET Research paper Biosynthesis of Zinc Oxide Nanoparticles for Corrosion Protection Application * Rabiatuladawiyah Md Akhir 1 , Mohamad Haziq Norashikin 2 , Mohd Muzamir Mahat 3 , Noor Najmi Bonnia 4 School of Physics and Material Studies, Faculty of Applied Sciences, Universiti Teknologi MARA, 40450, Shah Alam, Selangor, Malaysia. *Corresponding author E-mail: rabiatul9581@salam.uitm.edu.my Abstract The present study reports the successful synthesis of biosynthesized zinc oxide nanoparticles (ZnONPs). The Pandanus Amaryllifolius leaves extract was used as reducing agent with zinc nitrate hexahydrate as precursor. The effects of synthesis temperature on biosynthesis of ZnONP’s are discussed. The biosynthesized ZnONPs were characterized by X-ray diffraction (XRD) ; and they were found to exhibit the hexagonal wurtzite structure. The diffractograms revealed well-defined, strong and sharp peaks at 2θ positions that correspond to its crystallinity with average size of 16.25 nm. Micrograph images from Field Emission Scanning Electron Microscope (FESEM) have shown polydispersed spherical shape of the biosynthesized ZnONPs. Smaller grain sizes were produced at low synthesis temperature of 60ºC. The elemental composition analysis confirmed the presence of zinc and oxygen by Energy Dispersive X-ray (EDX). The corrosion inhibition efficiency of mild steel in 1.0 M hydrochloric acid (HCl) solution was determined by weight loss method. Of significance, good corrosion inhibition efficiency of 79.43% was obtained by incorporating the biosynthesized ZnONP’s at synthesis temperat ure of 60ºC. Keywords: Zinc oxide nanoparticles, corrosion protection, mild steel, biosynthesis, Pandanus Amaryllifolius. 1. Introduction Metal oxide nanoparticles is one of the multifunctional materials that can be manipulated into wide nanotechnology applications across all sciencetific fields, such as chemistry, biology, physics, materials science, and engineering. In case of nanoparticles, they are effectively a bridge between bulk materials and atomic or mo- lecular structures which draws the attention of scientific research- ers to focus on their synthesis. Among all metal oxide nanoparti- cles, zinc oxide nanoparticles (ZnONPs) are in the forefront of research due to their unique properties and wide applications [1]. ZnONPs exhibit high catalytic efficiency, high absorption of light, strong adsorption ability and fast electron transfer kinetics which make it a promising material in paint products, bio-sensing proper- ties, [2], [3] and hybrid solar cells [4]. Due to such a wide range of applications, numerous methods concerning the fabrication of ZnONPs have been developed. Chemical and physical processes such as sol-gel technique, solvothermal synthesis, chemical reduc- tion, laser ablation and inert gas condensation have been used in obtaining ZnONP’s [5-7]. Even though chemical method of syn- thesis has advantageous as it takes short period of time to synthe- size large quantities of ZnONP’s, however the process and yield could be toxic and lead to it having non-environmentally friendly by-products which may cause harm to human body in the long term. In addition, some chemical reactions require critical condi- tions of temperature and pressure as reported by [8]. Increasing awareness towards green synthesis (biosynthesis) of metal oxide nanoparticles has led to the development of an eco-friendly ap- proach for the synthesis of ZnONP’s. The techniques for obtaining nanoparticles using naturally occurring reagents such as vitamins, sugars, plant extracts, biodegradable polymers, and microorgan- isms as reductants and capping agents have been proven as pre- ferred alternative green synthesis [9-12]. Among the reagents mentioned above, plant based materials can be considered as the best candidates. Nanoparticles produced by plants are more varied in size and shape and more stable compared to those that are pro- duced by microorganisms [13] On top of that, they are suitable for large-scale biosynthesis of nanoparticles [14]. Although biosynthesis of ZnONP’s by plants such as Aloe bar- badensis miller [15], Azadirachta indica [16], Allium sativum [17] have been reported, the potential of plants as biological mate- rials for the synthesis of nanoparticles is yet to be fully explored. From this point of view, this study aims at the biosynthesis of ZnONPs from prepared Pandanus amaryllifolius leaves extract. Hence, the effect of both ZnONPs and Pandanus amaryllifolius as environmentally friendly corrosion inhibitor of mild steel in 1.0 M hydrochloric acid (HCl) solution by weight loss method have been investigated. It is strongly believed that flavonoids natural prod- ucts contained in Pandanus amaryllifolius are responsible to ex- hibit good corrosion inhibition efficiency. The effects of different synthesizing temperature on biosynthesis of ZnONPs is also dis- cussed. This novel synthesis of ZnONPs using aqueous extract of Pandanus amaryllifolius leaves can be utilized as a promising environmentally friendly corrosion inhibitor and simple alternative to alleviate the corrosion rate, protect metal surfaces against corro- sion and preserve industrial facilities.