Effect of substrate ratios on the simultaneous carbon, nitrogen, sulfur and phosphorous conversions in microbial fuel cells

Madiha Tariq; Jin Wang; Adeel Jalal Malik; Mohammed Salim Akhter; Qaisar Mahmood

doi:10.1016/j.heliyon.2021.e07338

Effect of substrate ratios on the simultaneous carbon, nitrogen, sulfur and phosphorous conversions in microbial fuel cells

Heliyon. 2021 Jun 17;7(6):e07338. doi: 10.1016/j.heliyon.2021.e07338. eCollection 2021 Jun.

Authors

Madiha Tariq¹, Jin Wang², Adeel Jalal Malik³, Mohammed Salim Akhter⁴, Qaisar Mahmood^{1

5}

Affiliations

¹ Department of Environmental Sciences, COMSATS University Islamabad, Abbottabad Campus, Pakistan.
² Department of Landscape and Architecture, School of Design, Shanghai Jiao Tong University, Shanghai 200240, China.
³ Department of Development Studies, COMSATS University Islamabad, Abbottabad Campus, Pakistan.
⁴ Department of Chemistry, College of Science, University of Bahrain, Bahrain.
⁵ School of Biotechnology and Food Engineering, Huanghuai University, Zhumadian 463000, China.

Abstract

The columbic efficiency, removal efficiency and voltage production of seven different combinations of carbon (acetic acid, albumin and sucrose) with nutrients (C:N, C:P, C:S, C:N:S, C:P:S, C:N:P and C: N:S:P) were investigated at three different ratios (20:1, 15:1 and 10:1). The effects of various pH values were also explored for these combinations of carbon, and sulfur compounds (pH 6-8). The highest columbic efficiency (75.8%), COD removal efficiency (86%) and voltage (667 mV) were recorded when the acetic acid was used in the MFC and the lowest columbic efficiency (12.8%), removal efficiency (37.6%) and voltage (145 mV) were observed in case of albumin. A marked increase in columbic efficiency, removal efficiency and voltage production were seen with the rise in the pH value from 6 to 8. The lowest columbic efficiency, removal efficiency and voltage production were seen at pH 6 and highest at pH 8. At each investigated pH, the highest removal efficiency, columbic efficiency, and voltage were found at substrate ratio of 20:1 while lower at 10:1. At all pH values, the carbon to nutrient ratios seemed to have followed a similar trend i.e., the COD removal efficiency, columbic efficiency and voltage generation was found in the order C:N > C:N:S > C:N:S:P > C:N:P > C:S > C:P:S > C:P. In all cases, nitrogen showed a higher removal as compared to phosphorous and sulfur.

Keywords: Bioenergy; Columbic efficiency; Electronic equivalents; Substrate ratios; Voltage generation.