Fast and cost-effective preparation of antimicrobial zinc oxide embedded in activated carbon composite for water purification applications

Activated carbon (AC) has been widely used for water purification. However, the microorganisms attached on the AC can result in microorganism secondary contamination in the purification process. Therefore, antimicrobial AC is being developed as a promising solution. In this paper, ZnO embedded activated carbon (ZnO-AC) is synthesized with an excellent antimicrobial property. The ZnO-AC is prepared using low cost and commercially available zinc oxide powder and granular AC. ZnO is embedded in-situ on the AC through a fast and simple immersion and heating process. EDX mapping and XPS spectra showed that ZnO was evenly embedded on AC. While the ZnO-AC had relatively low level of zinc concentration of 0.593 mg/g, it achieved a high reduction ratio of 99.99% towards E. Coli. To demonstrate the robust antimicrobial property of the ZnO-AC, tap water is applied for flushing. Results showed that ZnO-AC was able to reduce 91.18% of the E. Coli even after 500 L water flushing. Meanwhile, zinc leaching analysis demonstrated that ZnO-AC is safe to be used. Thus, the prepared ZnO-AC provided a promising solution in water purification industry.