Efficacy of ceramic water purifiers coated with colloidal Ag doped TiO₂ against polyaromatic hydrocarbons and pathogens in Sierra Leone

With the urgency and demand for access to safe drinking water still present across the developing world this paper assesses the potential for combining the photocatalytic properties of titanium dioxide (TiO₂) doped with silver (Ag) with the ceramic water purifier (CWP), a simple point of use water treatment device developed by Potters for Peace. The aim of the work is to provide a low cost, low energy and low environmental impact water treatment solution, suitable for use in rural and peri-urban Sierra Leone. The ability of TiO₂ and colloidal Ag to remove humic substances, ubiquitous organic contaminants (PAHs) and pathogens in solution and as a CWP coating has been investigated under similar conditions to those found in Sierra Leone. This study showed an almost complete removal of Escherichia coli using TiO₂, Ag or Ag doped TiO₂ coatings (>99%); a high removal (80%) of PAHs in the permeate by CWP coated with Ag doped TiO₂, and a removal of 40 and 60% HA in the permeate by CWP coated with Ag and TiO₂, respectively.