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

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.

Dynamic Inhibition of Calcite Dissolution in Flowing Acidic Pb2+ Solutions

“…Understanding this behavior will be important for enabling accurate predictions of the geochemical reactivity underlying various geological and environmental technologies. For example, the inhibition of calcite dissolution by dissolved metal cations would negatively impact the efficiency of passive remediation of mine tailings and acid mine drainages where limestone (up to 95% calcite) is used to buffer acidic waters typically characterized by elevated levels of dissolved metals. − Specifically, the inhibited dissolution of calcite could lead to a higher-than-expected mobility of contaminants under conditions where acid mine waters pass through limestone beds. A robust understanding of these metal–carbonate interactions would help in the development of more efficient remediation strategies for metal contaminants associated with mining activities.…”

Metal Recovery and Electricity Generation from Wastewater Treatment: The State of the Art

“…Cr(VI) To date, many reports have shown that the metal ion removal efficiency and electricity production performance in MFCs are mainly affected by the metal ion type and concentration, electrode materials, anode substrates, and microbe community [19,20]. It is very meaningful to better understand these factors and their effects on the system in order to develop efficient and applicable technologies for metal-polluted wastewater treatment.…”

Electrified bioreactors: the next power‐up for biometallurgical wastewater treatment

“…Ai et al . ( 2020 ) achieved the selective recovery of Cu, Cd and Fe by working under MFC or MEC mode, and Leon‐Fernandez et al . ( 2021 ) the sequential recovery of Cu (in MFC mode) and Sn, Ni and Fe (in MEC mode), also from simulated acid mine drainages (Ai et al ., 2020 ; Leon‐Fernandez et al ., 2021 ).…”

“…( 2020 ) achieved the selective recovery of Cu, Cd and Fe by working under MFC or MEC mode, and Leon‐Fernandez et al . ( 2021 ) the sequential recovery of Cu (in MFC mode) and Sn, Ni and Fe (in MEC mode), also from simulated acid mine drainages (Ai et al ., 2020 ; Leon‐Fernandez et al ., 2021 ). Finally, other studies have reported the coupling of bioanodes with the cathodic metal removal by precipitation as metal hydroxides or carbonates (Lefebvre et al ., 2012 ; Colantonio and Kim, 2016 ).…”