Statistical optimization of operational parameters using response surface methodology in polymer electrolyte membrane based microbial fuel cell for increased power production

Abstract

Increased concerns over depletion of fossil fuel, climate change and environmental pollution have led researchers around the world to make substantial and impactful efforts to explore new sustainable and eco-friendly energy resources. In recent decades, Bio-electrochemical systems (BES) exploit the process of bioelectrochemical utilization of organic substances via microbial metabolism to produce by-products, fuels and bio-electricity. In BES, particularly Microbial Fuel Cell (MFCs) that can yield energy from organic matter through microbial metabolism have attracted more attention as a prospective method for clean energy production and bioremediation. In MFC system, the microorganisms present in the substrate at the anode chamber consume the organic matter present to produce protons and electrons under suitable conditions. During MFC operation, the protons produced by the microorganisms passes through the Proton Exchange Membrane (PEM) and the electrons flow through a connected external circuit to reach the cathode. The travelled protons and electrons with a suitable electron acceptor are reduced at the cathode compartment, where, the flow of electrons produces electrical energy. There are many researches focused on MFC operation which have been applied based on wastewater treatment and recovery, electricity generation and modifications on electrode materials, membranes, design and configuration for enhanced power generation. Thus, the MFC operational parameters play an important role in the betterment of MFC performance. Although several novel membranes have been adapted to enhance the MFC performance through conventional and statistical analysis, the reports based on membranes and operational parameters optimization using statistical tools is still scarce, which plays a vital role in the enhancement of energy production in MFC operation. In the present research a thermoplastic elastomer, Poly (styrene ethylene butylene polystyrene) (PSEBS) with significant mechanical, thermal and chemical properties was selected as polymer. Further, the PSEBS was sulphonated using chlorosulphonic acid under optimum condition to obtain sulphonated PSEBS (SPSEBS). Fourier Transform Infra-red Spectroscopy (FTIR) was used to confirm the functionality of the synthesized SPSEBS. To improve the ionic conductivity and hydrophilic nature of the polymer SPSEBS, three nanofillers Polyhedral Oligomeric Silsesquioxane (POSS), Titanium Nanotube (TNT) and Zinc Oxide Nanorods (ZnO NR) were sulphonated and used in the present study. For the sulphonation process, the nanofiller POSS was sulphonated using chlorosulphonic acid under nitrogen atmosphere at 0°C to obtain SPOSS, whereas for the sulphonation of nanofiller TNT and ZnO NR, the TiO2 and ZnO nanoparticles were converted into titanium nanotubes and ZnO nanorods by adopting hydrothermal method and then sulphonated using concentrated sulphuric acid. newline