Effects of Ni nanoparticles, MWCNT, and MWCNT/Ni on the power production and the wastewater treatment of a microbial fuel cell

ABSTRACT

Ni nanoparticles (NPs), multi-walled carbon nanotubes (MWCNT), and MWCNT/Ni were compared for the first time in enhancing power production and wastewater treatment efficiency of a two-chambered microbial fuel cell (MFC). The cathode electrode – a 3D carbon fiber brush – was modified for the first time using different amounts of the three types of nanomaterials. Closed-circuit voltage of the cell was recorded, and chemical oxygen demand (COD) of the anode solution was measured with time. The overall performance of the MFC was enhanced in the following order: MWCNT > MWCNT/Ni > Ni. The power production increased by 7.9 times to 1.2 W/m³ with 1.5 mg/cm² of MWCNT. The power density further increased to 1.9 W/m³, and the COD maximally decreased by 163.3 mg/L in a 24-h duration with 3.0 mg/cm² of MWCNT. The internal resistance decreased maximally by 65.2% to 0.4 kΩ with 1.5 mg/cm² of MWCNT/Ni, and further to 0.3 kΩ with 3.0 mg/cm² of MWCNT/Ni. Electrochemical impedance spectroscopy (EIS) was conducted to assess the effects of different nanomaterials on the impedance of the MFC. Charge transfer resistance of the cathode was maximally reduced by ~85% to 0.3 Ω with 3.0 mg/cm² of MWCNT/Ni. Considering price, stability, and performance, MWCNT is the most practical material for cathode modification. This study is meaningful for sustainable wastewater treatment by enhancing energy production from wastewater treatment process through applying low-cost nanomaterials on the cathode of the MFC.

KEYWORDS:

• Microbial fuel cell
• wastewater treatment
• power production
• Ni nanoparticles
• MWCNT
• electrochemical impedance spectroscopy

Supplementary materials

Supplemental data for this article can be accessed on the publisher’s website.

Additional information

Funding

This research was supported by the Startup (to Jia Liu), Southern Illinois University, Carbondale; and REU Site in Interdisciplinary Materials Research, funded by National Science Foundation, USA, in May - July of 2017.