Regenerated silk fibroin membranes as separators for transparent microbial fuel cells

Grzegorz Pasternak,Yuejiao Yang,Bruno Bosquiroli Santos,Federico Brunello,Martin M Hanczyc,Antonella Motta

doi:10.1016/j.bioelechem.2018.12.004

Abstract

In recent years novel applications of bioelectrochemical systems are exemplified by phototrophic biocathodes, biocompatible enzymatic fuel cells and biodegradable microbial fuel cells (MFCs). Herein, transparent silk fibroin membranes (SFM) with various fibroin content (2%, 4% and 8%) were synthesised and employed as separators in MFCs and compared with standard cation exchange membranes (CEM) as a control. The highest real-time power performance of thin-film SFM was reached by 2%-SFM separators: 25.7 ± 7.4 μW, which corresponds to 68% of the performance of the CEM separators (37.7 ± 3.1 μW). Similarly, 2%-SFM revealed the highest coulombic efficiency of 6.65 ± 1.90%, 74% of the CEM efficiency. Current for 2%-SFM reached 0.25 ± 0.03 mA (86% of CEM control). Decrease of power output was observed after 23 days for 8% and 4% and was a consequence of deterioration of SFMs, determined by physical, chemical and biological studies. This is the first time that economical and transparent silk fibroin polymers were successfully employed in MFCs.

Highlights

Over the past decade, there has been expanding development of microbial fuel cells with the overall functionality of providing organic waste as input and generating electricity and other value added products as output
In this paper we present the use of a natural silk fibroin membrane (SFM) as a cation exchange membranes (CEM) substitute
The data derived from this initial period suggested that power performance of the microbial fuel cells (MFCs) could be positively correlated with the fibroin concentration in SFMs

Summary

Introduction

There has been expanding development of microbial fuel cells with the overall functionality of providing organic waste as input and generating electricity and other value added products as output. The MFC consists of an anode and cathode connected through conductive material to shuttle electrons as well as a semiselective exchange membrane that allows passage of protons to complete the circuit. Design of the MFC systems spans various size scales from microliters to pilot-scale reactors demonstrating power densities that make this technology useful and applicable [1,2,3]. With practical demonstrations of MFCs, advances in new technological solutions for every component of the fuel cell strive to improve its overall performance. The major engineering areas of interest consist of the anode, cathode [4,5,6], and microbial studies [7,8,9] In addition, the separator between the electrodes is an important element, affecting the performance of MFCs as well as the other types of bioelectrochemical systems.

Methods

Results

Conclusion