African Journal of Education, Science and Technology, May, 2017 Vol 3, No. 4 33 Synthesis, Characterization of ZnO Nanoparticles and their Application in Removal of Heavy Metals from Waste water Lucy J. Chebor School of Science, Department of Chemistry, University of Eldoret, Kenya lucychebor@yahoo.com Lusweti Kituyi School of Science, Department of Chemistry, University of Eldoret, Kenya joluki@yahoo.com Dickson Andala Kenyatta University, Kenya andalad@gmail ABSTRACT Water scarcity and its contamination with toxic metal ions represent a serious worldwide problem in the 21 st century and conditions are particularly bad in developing countries. In an effort to reduce the environmental and health effects of heavy metals in wastewater, various techniques have been employed. However, most of these techniques are expensive and ineffective in complete removal of heavy metals from the waters. Nanotechnology is a promising field in waste water treatment. This study aimed at assessing the efficiency of synthesized ZnO nanoparticles in adsorption of heavy metal ions from waste water. The objectives of this study were to synthesize ZnO nanoparticles, characterize and apply them y it in adsorption of heavy metals from waste waters. Precipitation technique was used to synthesize ZnO nanoparticles by synthesis of two samples L 1 and L 2 which were characterized using power X-ray diffraction (PXRD), fourier transform infra-Red (FTIR), scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX), methods of analysis. The PXRD results showed diffraction peaks which were indexed to ZnO reference as per JCPDS file 80-0075. The size of ZnO nanoparticles was found to be 26 nm. FTIR spectra showed a broad band at around 430 cm -1 with shoulder shape, characteristics of Zn-O bond. The images obtained by SEM showed rod shaped clusters of nanoparticles which were distributed well within a range of 100 nm which is a favorable property to exhibit better photo catalytic activity. The EDX results showed elemental composition of ZnO nanoparticles which showed 54% Zn, 44.07% O and 1.93% Mn impurities for L 1 and 55.34% Zn, 42.3% O and 2.37% Mn impurities for L 2 .The results of heavy metal ions adsorption showed an increase in percentage removal with increase in adsorbent dose and contact time. There was a decrease with increase in heavy metal concentration. Thus, ZnO nanoparticles can be used as an adsorbent of waste water from textile and metallurgical industries. Future studies could focus on possibilities of improving and commercializing this material through designing a treatment facility that incorporates commercial nano ZnO on large scale waste water treatment. Key Words: Heavy Metals, Adsorption, ZnO, Nanoparticles. INTRODUCTION Heavy metals such as cadmium and zinc in environments pose a serious threat to plants, animals and even human beings because of their bioaccumulation, nonbiodegradable property and toxicity even at low concentrations (Trivedi & Axe, 2000). In general, the pollution caused by heavy metals has detrimental effect on the environment all over the world. For example, a variety of toxic effects on aquatic organisms can be produced by endangering ecosystems; human health can be directly or indirectly influenced by multiple channels such as touching with skin, drinking water, and food chain. In addition, in agro-ecological environment, especially in soils, the phenomenon of heavy metals pollution is now quite common. Heavy metals cause great harm to the crop growth, yield and quality. So the removal of heavy metals, such as mercury, lead, zinc, copper, cadmium, and arsenic, from natural waters or soils has attracted considerable attention (Yantasee et al., 2007). The conventional technologies for the removal of heavy metal ions from aqueous solution include chemical precipitation, ion exchange, reverse osmosis, electrochemical treatment and adsorption (Elouear et al., 2008). Among the different treatments described above, adsorption technology is attractive due to its merits of efficiency, economy and simple operation (Crini, 2005). The common adsorbents primarily include activated carbons, zeolites, clays, biomass and polymeric materials (Elouear et al., 2008). However, these adsorbents described above suffer from low adsorption capacities and separation inconvenience. Therefore, efforts are still needed to exploit new promising adsorbents. Nanoparticles have two key properties that make them particularly attractive as sorbents. On a mass basis, they have much larger surface areas than bulk particles. Nanoparticles can also be functionalized with various chemical