Optimization of biomass carbon sources for simultaneous Pb(II) removal and bioelectricity generation in microbial fuel cell: based on agricultural waste types and pretreatment approaches

A single-chamber microbial fuel cell (MFC) employing pretreated agricultural wastes as carbon sources was constructed for the removal of Pb(II) from wastewater. For this, the performance for the effects of biomass types (straw, corncob, and wood chip) and pretreatment approaches (alkali-heat, high-pressure, and untreated) towards the Pb(II) treatment as well as bioelectricity generation was systematically investigated to determine the optimal biomass carbon source. The carbon release characteristics of pretreated biomass were monitored regularly, and the straw after alkali-heat pretreatment (AT-S) was screened as the most effective promoter to enable a sustaining supplementation of carbon sources. AT-S-MFC yielded a favorable Pb(II) removal efficiency of 87.66% as well as a maximum output voltage of 184.4 mV. The power density of the device displayed a remarkable upward trend with the increasing biomass dosage, and the maximum value of 1556.34 mW/m(2) was acquired. The potential for Pb(II) migration suggested that approximately 78% of Pb(II) in the system was adsorbed by the biomass and 10% was enriched on the electrode. AT-S-MFC cathode was systematically characterized to manifest the homogeneous deposition of Pb on the surface area. The obtained XPS results provided evidence for the reduction and removal of Pb(II) metal ions on the cathode. As a result, the biomass AT-S has great potential to be an alternative carbon source in the MFC system for enhanced Pb(II) remediation from contaminated waters. Overall, this study was dedicated to providing theoretical guidance for effective regulation of MFC treatment on Pb(II)-containing wastewater and accompanied by bioelectricity generation via the resource utilization of agricultural wastes.