因為現存的水消毒劑程序會產生消毒副產物，所以產生尋求替代方案之研究需求，在諸多替代技術中，奈米級的氧化鋅因為具有抗菌作用，廣泛引起研究之興趣。因此，本研究使用不同方法合成奈米級氧化鋅，合成後之產品以XRD, SEM, EDS及BET 鑑定其特性，結果顯示所合成之產品確實為氧化鋅，粒徑顆粒約在43 nm左右。隨後將各種不同條件下所合成之氧化鋅進行抗菌測試，結果顯示，所合成的氧化鋅具有中度抑制E. coli 的功效。本研究同時也討論奈米鋅合成條件對抗菌能力之影響，例如藥劑用量、種類及燒結溫度的影響。統計結果顯示，不同合成藥劑種類及濃度影響所合成氧化鋅之抗菌能力，由本研究之結果同時也得知，為增加氧化鋅之抗菌能力，未來需近一步研究。 The limitations of existing technologies for water disinfection particularly the formation of disinfection-by-products, have led to researches on alternative methods. Zinc oxide, specifically in the nanoscale, has attracted research interest as antimicrobial agent. In this study, the ZnO nanoparticles were synthesized by direct precipitation method using zinc nitrate hexahydrate as zinc source and reacted with different precipitating agents such as sodium hydroxide, potassium hydroxide and ammonium carbonate. The synthesized products were characterized by XRD, SEM, EDS and BET. Characterization results ascertained that the product was ZnO with particle sizes with an average of 43 nm. The synthesized zinc oxide samples were tested for their antibacterial properties using standard microbiological methods for disk diffusion. The zone of inhibition, which measures antibacterial activity, showed that the synthesized zinc oxide nanoparticles exhibited antibacterial effect against E. coli. The study also looked into the effect of varying parameters such as dosage, calcination temperature, and precursors. Statistical analysis showed that the effect of varying dosage and precursors used had significant effect on the antibacterial activity, while there was no significant difference in the antibacterial activity across the calcination temperature range used in the experiments. The promising results of ZnO nanoparticles antibacterial activity suggest that its usage in water disinfection as antibacterial agent requires further investigations.