Electrolyte-concentration Cell using Bruguiera Gymnorrhiza

Abstract

An electrolyte-concentration cell was fabricated and its power generating characteristics were evaluated for the first time using salt-tolerant plant Bruguiera Gymnorrhiza. This plant is known to grow in sea water and the chloride concentration in sap is lower than that in the saline surrounding the root.^1,2) Plant tissue that separated the saline and the sap usually contains several ions like potassium and calcium, and was thought to show ionic conductivity. An electrolyte-concentration cell was, therefore, thought to be able to fabricate using the chloride ion concentration difference and the ionic conductivity. One of the two Ag/AgCl electrodes was inserted into the petiole of the plant, and the other among the vermiculites that supported the plant root. The vermiculites were soaked in a 400 mM NaCl solution. Two electrodes were connected to a galvanostat and the voltage was measured under a fixed current (20 nA) mode. The voltage gradually decreased with time from 260 mV to ca. 175 mV in two weeks. A periodical change in the voltage was observed. The internal resistance of the system was estimated to be 1.78 GΩ.