Investigation on electrical surface modification of waste to energy ash for possible use as an electrode material in microbial fuel cells

Abstract

With the world population expected to reach 8.5 billion by 2030, demand for access to electricity and clean water will grow at unprecedented rates. Municipal solid waste combusted at waste to energy (WtE) facilities decreases waste volume and recovers energy, but yields ash as a byproduct, the beneficial uses of which are actively being investigated. Ash is intrinsically hydrophobic, highly oxidized, and exhibits high melting points and low conductivities. The research presented here explores the potential of ash to be used as an electrode material for a microbial fuel cell (MFC). This application requires increased conductivity and hydrophilicity, and a lowered melting point. Three ash samples were investigated. By applying an electric potential in the range 50-125 V across the ash in the presence of water, several key property changes were observed: lower melting point, a color change within the ash, evidence of changes in surface morphologies of ash particles, and completely wetting water-ash contact angles. We analyzed this system using a variety of analytical techniques including sector field inductively coupled plasma mass spectrometry, scanning electron microscopy, X-ray diffraction, differential scanning calorimetry, and tensiometry. Ability to make such surface modifications and significant property changes could allow ash to become useful in an application such as an electrode material for a MFC.

Bioenergy Production from Tannery Waste via a Single-Chamber Microbial Fuel Cell with Fly Ash Cathodic Electrodes

“…There is also an attempt to create a binding geopolymer that will replace classic cement [18,19], as well as the production of more durable ceramic building materials (modern bricks) [16,20]. In addition to the above traditional applications, intense research has been reported in recent years on the use of FA in the fuel cell industry to produce more efficient electrodes [21] and polymeric electrolytic membranes [22]. Also, the simultaneous utilization of FA and sewage sludge has led to the construction of high-performance anodes for MFCs [23], while research effort is also expanding in the field of ion-lithium battery performance optimization, by adding a film of FA to the cathode [24].…”