The Workman-Reynolds Effect: An Investigation of the Ice-Water Interface of Dilute Salt Solutions

Introduction As a dilute aqueous solution of salt rapidly freezes, ions in solution become preferentially differentiated at the ice-water interface. The Workman-Reynolds Effect (WRE) is the resulting potential that forms between the ice and its constituent dilute salt solution. This potential can range from a few to ~230 volts with the magnitude and sign of the potential being primarily dependent on the type of salt, concentration of ions, and freezing rate. As a result, the electrolysis of water could lead to significant H2 and O2 gas production that has the potential to drive the production of life on Snowball Earth and icy satellites such as Europa and Enceladus. Limmited work has been done on the WRE, primarily focusing on dilute solutions of 10 to 10 molar NaCl, and results are largely inconsistent, ranging from ~20 to 43 volts for NaCl [1-6]. Our experiments with 10 molar solutions of NaCl, KCl, and NH4Cl validate the WRE, though our observations conflict with those previously published. We find a WRE of only ~6-10 volts for NaCl. Differences in pH between the resulting ice and water have also been observed [1,2]. Early results demonstrate the factors that affect the outcome of the WRE and gives direction for controlled experiments for further exploration in this topic.