Improving prussian blue electrodes for salinity and organic energy recovery from wastewater
Abstract/Contents
- Abstract
- In current wastewater treatment plants, dissolved organics and salt gradients are vast untapped energy resources. Microbial batteries (MBs) operate with a bio-anode to oxidize organic matter in wastewater, with a solid-state cathode as an electron receiver. Mixing entropy batteries (MEBs) are redox systems that capture salinity gradient energy; applicable for systems such as treated wastewater being discharged to coastal waters. For coastal treatment plants that adopt both kinds of recovery technologies, this energy could power the plant. This study aims to improve the Prussian blue (PB) cathodes of these batteries to prepare for their future scale-up. This work focuses on a method to protect PB electrodes and stabilize long-term performance using a thin layer of cation exchange polymer on the electrode surface. Results indicated that the polymer improved the performance of PB electrodes in several ways. First, there was no detachment of PB due to mechanical abrasion, demonstrating a reasonably practical mechanical strength. Second, the capacity retention, an important characteristic for long-term use of a battery, improved to ~97% for 190 cycles (around 16 days). By comparison, uncoated PB electrodes had 90% retention over 50 cycles. Third, results indicated that the sulfosuccinic acid (SSA) component of the polymer reduced electrode overpotential by 40 to 51% depending on the proportion of SSA in the polymer, electrolyte concentration, and current density. The coating layer enabled use of a stainless steel wire mesh as a current collector instead of expensive and fragile carbon cloth. The coulombic efficiency and capacity of the stainless steel mesh electrode were nearly constant over 150 charge/discharge cycles. The stainless steel mesh required ~60% less PB than the carbon mesh for recovery of the same amount of net energy per cycle. Coated PB was evaluated as a cathode material in an 800-ml automatic-operated microbial battery. Results demonstrated that the coated PB can be applied for use in microbial batteries with short-term performance that is similar to that of an uncoated electrode. Long-term experiments are needed to understand the performance and biofouling behavior of the PB coated electrode.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2017 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Xu, Jianqiao |
|---|---|
| Associated with | Stanford University, Civil & Environmental Engineering Department. |
| Advisor | Criddle, Craig |
| Thesis advisor | Criddle, Craig |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | Jianqiao Xu. |
|---|---|
| Note | Submitted to the Department of Civil and Environmental Engineering. |
| Thesis | Thesis (Engineering)--Stanford University, 2017. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2017 by Jianqiao Xu
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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