900-Days long term study of plant microbial fuel cells and complete application for powering wireless sensors

Abstract

Plant microbial fuel cells (PMFCs) are electrochemical systems capable of producing electrical energy from plant growth. Despite their limited power density, PMFCs hold pomise as power source for wireless sensor, without using embedded battery, especially in isolated locations. In this study, a complete wireless system was presented, with Cyperus papyrus-based microbial fuel cell. The Cyperus papyrus system was studied over 900 days. Although there was a slight decrease in power output attributed to anodic decreasing performance, the reduction at the cathode remained stable. This stability is likely due to biocatalyst activity, supported by the oxygen transport from the plant to the roots. Although performance of Cyperus papyrus microbial fuel cell were lower than those found in literature, these plants were stacked to power a microcontroller equipped with a temperature/humidity sensor. This microcontroller transmitted measurements wirelessly to a web server every 2 h. The web server, accessible via a web interface, provided real-time data to users on the local network. Finally, the intervals between measurements could serve as indicators of environmental stress, such as variations in soil moisture content.