title: Enhanced MFC power production and struvite recovery by the addition of sea salts to urine.
abstract: Urine is an excellent fuel for electricity generation in Microbial Fuel Cells (MFCs), especially with practical implementations in mind. Moreover, urine has a high content in nutrients which can be easily recovered. Struvite (MgNH4PO4·6H2O) crystals naturally precipitate in urine, but this reaction can be enhanced by the introduction of additional magnesium. In this work, the effect of magnesium additives on the power output of the MFCs and on the catholyte generation is evaluated. Several magnesium sources including MgCl2, artificial sea water and a commercially available sea salts mixture for seawater preparation (SeaMix) were mixed with real fresh human urine in order to enhance struvite precipitation. The supernatant of each mixture was tested as a feedstock for the MFCs and it was evaluated in terms of power output and catholyte generation. The commercial SeaMix showed the best performance in terms of struvite precipitation, increasing the amount of struvite in the solid collected from 21% to 94%. Moreover, the SeaMix increased the maximum power performance of the MFCs by over 10% and it also changed the properties of the catholyte collected by increasing the pH, conductivity and the concentration of chloride ions. These results demonstrate that the addition of sea-salts to real urine is beneficial for both struvite recovery and electricity generation in MFCs.
authors.affiliation: Bristol BioEnergy Centre, Bristol Robotics Laboratory, University of the West of England, BS16 1QY, UK. Electronic address: Irene.Merinojimenez@uwe.ac.uk.
authors.forename: Irene
authors.initials: I
authors.lastname: Merino-Jimenez
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
authors.forename: Veronica
authors.initials: V
authors.lastname: Celorrio
authors.affiliation: School of Chemistry, University of Bristol, Cantock's Close, Bristol, BS8 1TS, UK.
authors.forename: David J
authors.initials: DJ
authors.lastname: Fermin
authors.affiliation: Bristol BioEnergy Centre, Bristol Robotics Laboratory, University of the West of England, BS16 1QY, UK; Biological, Biomedical and Analytical Sciences, University of the West of England, BS16 1QY, UK.
authors.forename: John
authors.initials: J
authors.lastname: Greenman
authors.affiliation: Bristol BioEnergy Centre, Bristol Robotics Laboratory, University of the West of England, BS16 1QY, UK; Biological, Biomedical and Analytical Sciences, University of the West of England, BS16 1QY, UK. Electronic address: ioannis.ieropoulos@brl.ac.uk.
authors.forename: Ioannis
authors.initials: I
authors.lastname: Ieropoulos
mesh_terms: D001674:Bioelectric Energy Sources; D004560:Electricity; D006801:Humans; D008274:Magnesium; D017616:Magnesium Compounds / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D012492:Salts; D000069877:Struvite; D014556:Urine / Q000737:chemistry*
chemical_list: D017616:Magnesium Compounds; D010710:Phosphates; D012492:Salts; D000069877:Struvite; D008274:Magnesium
keywords: Catholyte generation; Ceramic membrane; Microbial fuel cell (MFC); Struvite recovery; Urine treatment