Electrochemistry at Deep-Sea Hydrothermal Vents: Utilization of the Thermodynamic Driving Force towards the Autotrophic Origin of Life

Significance 

Applied chemical processes require efficient utilization of energy. For instance, in industrial chemical synthesis, energy efficiency is among the vital parameters used to determine the economic benefits and industrial feasibilities of different chemical processes. Therefore, understanding the various factors controlling the usability of thermodynamic driving forces in driving chemical reactions efficiently is of great significance. Presently, studies on the deep-sea hydrothermal vents and the surroundings have been primarily based on determining the unique strategies for efficiently using the alternative energy sources considering the unavailability of sunlight, which is the main terrestrial energy sources in the ecosystems. This will also ensure effective use of temperature gradients as an alternative source of energy for chemical reactions.

Recently, Biofunctional Research Team from RIKEN Center for Sustainable Resource Science: Dr. Hideshi Ooka, Dr. Shawn E. McGlynn and Professor Ryuhei Nakamura investigated the various chemical processes at deep-sea hydrothermal vents to understand the thermodynamic driving force towards the autotrophic origin of life. In particular, they presented strategies that can be used in the amplification of the driving force using temperature. Additionally, they investigated the feasibility of using spatially separated thermodynamic gradients for regulating reaction selectivity. Their research work is currently published in the research journal, Chemelectrochem.

Prior to this this study, the authors initially published a research work where they tried to understand the energy and chemical conversion taking place at deep-sea hydrothermal vents. In this paper, a review of the past study is presented, with the main objective being to understand how thermal energy can be produced from the deep-sea hydrothermal vents as well as its use in facilitating difficult chemical reactions such as carbon dioxide reactions. Specifically, they investigated the ability of electrically conductive and thermally insulative chimney wall to sufficiently decrease the electrochemical potential. The electrochemical driving force was manipulated based on the Nernst equation and chemical disequilibria that existing across the conducting barrier. To ascertain the practicability of the proposed strategies, their implementation on the metal sulfide minerals such as those obtained from deep-sea hydrothermal vents was discussed.

The unique differences in the deep-sea hydrothermal vents and the terrestrial environments were noted. However, the authors confirmed the possibility of harnessing thermal and chemical energy from the deep-sea environments and using it to drive specific chemical reactions. This was attributed to the thermal insulation and electrical conductivity properties of the chimney walls that ensured the stability of both thermal and chemical gradients. The stability led to variations in the reaction environments that would further result in the creation of a suitable environment for specific chemical reactions such as carbon dioxide reduction. This selectivity was due to electrochemical reactions that exhibited different pH and potential dependencies depending on the nature of the reactions involved.

The study presents insights that rekindle the hope of developing a clean and sustainable chemical process at high pressure and thermal temperatures. This is based on the principles involved in the establishment and utilization of thermodynamic driving force at hydrothermal vents. Altogether, efficient utilization of heat at the deep-sea hydrothermal vents is a promising solution in ensuring efficiency and sustainability of future industrial chemical processes.

Reference

Ooka, H., McGlynn, S., & Nakamura, R. (2019). Electrochemistry at Deep-Sea Hydrothermal Vents: Utilization of the Thermodynamic Driving Force towards the Autotrophic Origin of Life. Chemelectrochem, 6(5), 1316-1323.

Go To Chemelectrochem

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