|Title||Bioelectrochemical metal recovery with microbial fuel cells|
|Author(s)||Rodenas Motos, Pau|
|Source||University. Promotor(en): Cees Buisman, co-promotor(en): Annemiek ter Heijne; Tom Sleutels. - Wageningen : Wageningen University - ISBN 9789463430968 - 126|
Sub-department of Environmental Technology
|Publication type||Dissertation, internally prepared|
This thesis aims to explain the metal recovery through the study of their components using Copper as a model compound of the heavy metals. Different electrochemical cells distribution and sizes were used to improve efficiency and current density. Two different electron donors were tested, acetate as a model compound from the organic matter fermentation and hydrogen as a model compound of inorganic electron donor used in industry. Chapter 1 of the thesis is an introduction to the topic. Chapter 2 shows how a reduction in internal resistance results in a step forward in the power production and current density of an MFC that couples acetate oxidation to copper reduction with an anion exchange membrane. This chapter also identifies limitations of the technology. One of these constraints is the availability of organic electron donor. In remote areas, the technology can be attractive in places where organic electron donors are available. In many places that have metal-containing waste streams, however, no such organic electron donors are available. Therefore, Chapter 3 investigated hydrogen as an electron donor for copper recovery. Hydrogen is available as a waste stream in the metal production industry. We show that hydrogen can be oxidized biologically at a bio-anode, and can be combined with copper recovery while producing electricity. One of the limitations that limited power production was a mass transfer of hydrogen from the gas phase to the biofilm. In Chapter 4, we studied the use of a gas diffusion electrode to improve mass transfer of hydrogen at a bio-anode. Chapter 5 focuses on an up-scaled design of the MFC for copper recovery using as a model the electroplating baths from metallurgy industry. Because considerable energy losses occur in a bipolar membrane, we investigated if carbon dioxide could be used as a charge carrier, resulting in lower energy losses. In Chapter 6, the improvements are discussed with relation to existing technologies, and an outlook for practical application is given.