Electricity generation enhancement in microbial fuel cell via employing a new SPEEK based proton exchange membrane modified by goethite nanoparticles functionalized with tannic acid and sulfanilic acid

Abstract

In this work, hydrophilic nanoparticles of goethite and its derivatives with functional groups of tannic acid and sulfanilic acid were prepared. The synthesized nanocomposites were embedded into sulfonated poly ether ether ketone (SPEEK) as base polymer of proton exchange membrane (PEM) for improvement of microbial fuel cell (MFC) performance. The SEM images, FTIR and AFM tests and contact angle measurements verified hydrophilic properties of the fabricated membranes. Proton exchangeability of the fabricated PEMs was examined in a two-chamber MFC under the same operating conditions (initial COD and biomass concentration of 3300 and 1500 mg/l, respectively). The MFC performance was assessed in terms of COD removal, coulombic efficiency, power density and current density. The best result was obtained from SPEEK nanocomposite membrane with goethite 0.5% wt. The proposed PEM showed significant improvement in terms of the maximum power density (73.7 mW/m 2 ) and current density (293 mA/m 2 ) compared to the bare membrane. A relatively high coulombic efficiency of 52.6% with COD removal of 97.6% was achieved. • Goethite NPs comparing to its derivatives with functional group of tannic acid and sulfanilic acid was a desirable modifier. • The optimal fabricated proton exchange membrane of SPEEK-goethite 0.5 %wt. showed an excellent performance in MFC. • The maximum power density and coulombic efficiency achieved for the optimal PEM were 73.7 mW/m2 and 52.6%, respectively. • Performance of the MFC operated with the selected PEM in terms of COD removal efficiency was 97.6%. • The reliability of the MFC was confirmed by testing its power to lighten red LED bulbs when four MFCs connected in series.