Preparation of Copper Oxide (CuO) Nanoparticles and their Bactericidal Activity

Single crystalline nanoparticles of copper oxide (CuO) having almost uniform particle size of ~40±10nm have been synthesized by a facile and versatile route. The technique employed is free from toxic solvents, organics, and amines, and is based on a simple reaction of copper powder and de-ionized water (DI) at very low temperatures of 180oC. The morphology, chemical composition, and crystalline structure of the nanoparticles were carefully investigated by the various characterization techniques. Besides simplicity, the advantages of producing nanoparticles by this method are that it is easeful, flexible, fast, cost effective, and pollution free. The synthesized nanoparticles are under investigations for various applications including their antibacterial activity. carbon monoxide, hydrocarbon and phenol in supercritical water. CuO can also be used as gas sensor, optical switch, magnetic storage media, lithium batteries and solar cells owing to its photoconductive and photochemical properties (Sambandan et al., 2005; Liu et al., 2006). It is well known that copper oxide have been used to disinfect liquids, solids and human tissue for centuries. Today it is used as water purifier, an algaecide, a fungicide and a nematocide as well as an antibacterial and antifouling agent (Ren et al., 2009). It is well known that copper oxides can be conveniently obtained by thermal decomposiDOI: 10.4018/ijmmme.2011100104 International Journal of Manufacturing, Materials, and Mechanical Engineering, 1(4), 58-64, October-December 2011 59 Copyright © 2011, IGI Global. Copying or distributing in print or electronic forms without written permission of IGI Global is prohibited. tion of copper salts (Han et al., 2008; Wang et al., 2002; Mang et al., 2008; Xu et al., 1999). However, it is too difficult to control the grain size of resulting copper oxide (CuO) particles through methods available, which is one of the essential requirements/conditions for the synthesis of nanomaterials. Moreover, the production in all cases required either elevated temperatures including prolonged reactions under special conditions or other tedious procedures in presence of harmful gases. In addition, most of the pathways suggested for the synthesis of CuO nanocrystals involve environmentally malignant chemicals and organic solvents which are toxic and not easily degraded in the environment. Environmental friendly chemical synthesis requires alternative solvents such as ionic liquids, liquid and water. Water is particularly attractive because it is inexpensive, safe, environmentally benign and bestowed with many virtues especially under supercritical conditions (Vostriko et al., 2009). Encouraged by the interesting and useful results (Shah et al., 2009), we decided to apply the approach to copper metal. Interestingly, uniform sized nanoparticles were obtained by a simple reaction of copper powder and de-ionized water at very low temperature of 180oC. The diameter of nanoparticles ranges from 30-50nm with an average diameter of 40nm. The bactericidal efficacy of the as prepared nano-CuO against Escherichia coli (Grame negative) and Staphylococcus aureus (Grame positive) bacteria was investigated. The reported method besides being organics free is economical, fast, environmentally benign and free of pollution, which will make it suitable for large scale production. The aim of the study is to provide the feasibility of the simple route for the preparation of copper oxide nanostructures without additives and to test their antibacterial efficiency. The prospects of the process are bright and promising.