Development of substrate-loaded microbial fuel cells for powering remote sensors
Abstract
Development of substrate-loaded microbial fuel cells for powering remote sensors Naval operations often rely on sensors that are deployed in the ocean. These sensors are meant to operate for long periods of time, but are often limited by their energy supply. Replacement of batteries, often used to power these sensors, is cost prohibitive. The development of sediment microbial fuel cells (MFCs) can lead to a reliable, continuous power supply for sensors at the ocean floor. In sediment MFCs, anode-respiring bacteria (ARB) use organic compounds from the sediments as substrate, generating electrical power. Nonetheless, current efforts show that sediment MFCs are often limited by the scarce amount of organic material present in sediments. Our proposed approach is to create an MFC that can be deployed with its substrate, providing years of continuous power supply. This approach is advantageous, because ARB can utilize a wide range of high energy density organic compounds that are cheap and safe. Through this approach, the anode is an enclosed system with optimized conditions for ARB growth, while a solid substrate continuously dissolves as ARB consumes it, ensuring a high substrate concentration at all times, and thus overcoming one of the most important challenges of the current generation of sediment MFCs. In order to design this MFC, we must first test several substrates in Task 1 to ensure that ARB can grow on them at high concentrations. Three substrates have been identified: cellulose, pyruvate, and succinate. These substrates will be tested with pure and mixed culture ARB cultures in two-chamber microbial electrolysis cells that include a high-surface anode made from carbon fiber. We will determine the maximum current densities and Coulombic efficiencies we can achieve with the substrates and cultures. At the end of Task 1, we will select one substrate along with one culture that results in the highest current densities and Coulombic efficiencies, for further testing in Task 2 and 3. In Task 2, several MFC designs will be evaluated. We will study two types of cathodic reactions. First is a cathode that utilizes oxygen from the seawater (similar to a sediment MFC); in this cathode, a careful consideration of ionic currents will play an important role in its design. The second cathode will be fed with an oxidant, hydrogen peroxide, making the system completely enclosed and independent of its environment. Several materials (e.g., catalysts, polymers) will be evaluated during task 2 to reach successful and reliable MFC designs. For Task 3, we will partner with Dr. Bart Chadwick’s group at SPAWAR Systems Center Pacific/Coastal Monitoring Associates to test our best two designs in a coastal deployment. Through this Task, a continuous monitoring of the designs will be performed over a 9-month period, while changes to the design will be implemented if the power production is not optimal during deployment. Through the proposed work, we expect to have a successful MFC capable of producing 0.3 W and scalable to produce higher power due to its modular design. This design can be implemented in further testing and deployments that assess their feasibility to power remote sensors.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 08, 2016
- Source ID
- N000141512571
Entities
People
- César I. Torres
Organizations
- Arizona State University
- Office of Naval Research
- United States Navy