Recovery of Metals from Acid Mine Drainage by Bioelectrochemical System Inoculated with a Novel Exoelectrogen, Pseudomonas sp. E8

Chenbing Ai; Shanshan Hou; Zhang Yan; Xiaoya Zheng; Charles Amanze; Liyuan Chai; Guanzhou Qiu; Weimin Zeng

doi:10.3390/microorganisms8010041

Recovery of Metals from Acid Mine Drainage by Bioelectrochemical System Inoculated with a Novel Exoelectrogen, Pseudomonas sp. E8

Microorganisms. 2019 Dec 24;8(1):41. doi: 10.3390/microorganisms8010041.

Authors

Chenbing Ai^{1

2

3}, Shanshan Hou^{2

4}, Zhang Yan^{2

4

5}, Xiaoya Zheng^{2

4}, Charles Amanze^{2

4}, Liyuan Chai^{1

3}, Guanzhou Qiu^{2

4}, Weimin Zeng^{2

4}

Affiliations

¹ School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China.
² School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, Hunan, China.
³ Chinese National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Central South University, Changsha 410083, Hunan, China.
⁴ Key Laboratory of Biometallurgy of Ministry of Education, Central South University, Changsha 410083, Hunan, China.
⁵ College of Environmental Science and Engineering, Fujian Key Laboratory of Pollution Control & Resource Reuse, Fujian Normal University, Fuzhou 350007, Fujian, China.

Abstract

Acid mine drainage (AMD) is a typical source of environmental pollution ascribing to its characteristics of high acidity and heavy metal content. Currently, most strategies for AMD treatment merely focus on metal removal rather than metal recovery. However, bioelectrochemical system (BES) is a promising technology to simultaneously remove and recover metal ions from AMD. In this study, both cupric ion and cadmium ion in simulated AMD were effectively recovered by BES inoculated with a novel exoelectrogen, Pseudomonas sp. E8, that was first isolated from the anodic electroactive biofilm of a microbial fuel cell (MFC) in this study. Pseudomonas sp. E8 is a facultative anaerobic bacterium with a rod shape, 0.43-0.47 μm wide, and 1.10-1.30 μm long. Pseudomonas sp. E8 can agglomerate on the anode surface to form a biofilm in the single-chamber MFC using diluted Luria-Bertani (LB) medium as an energy substrate. A single-chamber MFC containing the electroactive Pseudomonas sp. E8 biofilms has a maximum output voltage of 191 mV and a maximum power density of 70.40 mW/m², which is much higher than those obtained by most other exoelectrogenic strains in the genus of Pseudomonas. Almost all the Cu²⁺ (99.95% ± 0.09%) and Cd²⁺ (99.86% ± 0.04%) in simulated AMD were selectively recovered by a microbial fuel cell (MFC) and a microbial electrolysis cell (MEC). After the treatment with BES, the high concentrations of Cu²⁺(184.78 mg/L), Cd²⁺(132.25 mg/L), and total iron (49.87 mg/L) in simulated AMD were decreased to 0.02, 0.19, and 0 mg/L, respectively. Scanning electron micrograph (SEM), energy dispersive X-ray spectrometry (EDXS) and X-ray diffraction (XRD) analysis indicate that the Cu²⁺ and Cd²⁺ in simulated AMD were selectively recovered by microbial electrochemical reduction as Cu⁰ (together with trace amounts of Cu₂O) or Cd⁰ on the cathode surface. Collectively, data suggest that Pseudomonas sp. E8 has great potential for AMD treatment and metal recovery.

Keywords: acid mine drainage; exoelectrogen; metal recovery; microbial electrolysis cell; microbial fuel cell.

Abstract

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