Naturally occurring metal oxides from rocks as capacitive deionization electrode materials for antibacterial activities

Abstract

The availability of clean and safe drinking water remains a prominent challenge in most parts of the world. Drinking water should be free from harmful microorganisms, salt as well as other organic and inorganic contaminants that need attention as they have health impacts on human beings. In the present study, naturally occurring metal oxides from rocks embedded in activated carbon (AC/MO) electrodes were evaluated for desalination and anti-bacterial activities against gram-negative (Escherichia coli) and gram-positive (Salmonella aureus) bacteria using capacitive deionization (CDI) technique. The AC/MO electrodes were fabricated for desalination and disinfection of natural and synthetic water with the CDI method. The AC/MO electrode materials were characterized by Scanning Electron Microscope (SEM), Energy Dispersive X-Ray (EDX), X-Ray Diffraction (XRD), X-Ray Fluorescence (XRF), and Fourier-Transform-Infrared spectroscopy (FTIR), and Transmission Electron Microscope (TEM) which affirm the formation of disinfecting electrode materials. The desalination and disinfection CDI experiments were conducted by carrying out batch mode laboratory CDI system using natural water collected from the Nduruma stream (natural water) while applying a potential difference of 1.2V for 4 h. It was found that the AC/MO CDI electrodes achieved 100 ± 0.42% E. coli and 60 ± 0.53% S. aureus bacteria removal and 46.85 ± 0.49% salt removal efficiency. The bacterial disinfection mechanism is through the CDI process and physical adsorption. Therefore, this study presents the AC/MO electrode material which can be considered as an appreciable anti-bacterial agent for the CDI performance