Porous ceramic tablet embedded with silver nanopatches for low-cost point-of-use water purification

Environ Sci Technol. 2014 Dec 2;48(23):13901-8. doi: 10.1021/es503534c.

Abstract

This work describes a novel method to embed silver in ceramic porous media in the form of metallic silver nanopatches. This method has been applied to develop a new POU technology, a silver-infused ceramic tablet that provides long-term water disinfection. The tablet is fabricated using clay, water, sawdust, and silver nitrate. When dropped into a household water storage container, the ceramic tablet releases silver ions at a controlled rate that in turn disinfect microbial pathogens. Characterization of the silver-embedded ceramic media was performed using transmission electron microscopy. Spherical-shaped patches of metallic silver were observed at 1–6 nm diameters and confirmed to be silver with energy dispersive spectroscopy. Disinfection experiments in a 10 L water volume demonstrated a 3 log reduction of Escherichia coli within 8 h while silver levels remained below the World Health Organization drinking water standard (0.1 mg/L). Silver release rate varied with clay mineralogy, sawdust particle size, and initial silver mass. Silver release was repeatable for daily 10 L volumes for 154 days. Results suggest the ceramic tablet can be used to treat a range of water volumes. This technology shows great potential to be a low-cost, simple-to-use water treatment method to provide microbiologically safe drinking water at the household level.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Ceramics / chemistry*
  • Disinfectants / chemistry
  • Disinfectants / economics
  • Disinfection / economics
  • Disinfection / methods
  • Escherichia coli / isolation & purification
  • Metal Nanoparticles / chemistry*
  • Microscopy, Electron, Transmission
  • Silver / chemistry*
  • Water Microbiology
  • Water Purification / economics
  • Water Purification / instrumentation*
  • Water Purification / methods*

Substances

  • Disinfectants
  • Silver