# Metal Recovery from Wastes: A Review of Recent Advances in the Use of Bioelectrochemical Systems
## 2 Bioelectrochemical Systems for Metal Recovery
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**Objective** & **Reactor Setup** & **Operational Conditions** & **Milestones** & **Ref.** \\ \hline  & System: Dual-chamber MFC & Analytic Synthetic medium with & -Cu recovery: 91\% (CaH), 85\% & \\  & Anode: Carbon felt (CF) and doped variants & acetate (1000 mg/L pH 7) & (CFnH), 48\% (CF) & \\  & with non-activated (CFnH) or activated & Catholyte Synthetic AMD (400 mg/L & - Faster Cu recovery (3 days vs. \\ metals from AMD & (2.5 \(\times\) 2.5 \(\times\) 0.8 cm) & Cu\({}^{2+}\), 400 mg/L Fe\({}^{2+}\), 50 mg/L Ni\({}^{2+}\), & 4 days) with doped anodes & [10] \\  & Cathode: Copper (2.5 \(\times\) 2.5 cm) & 50 mg/L Fe\({}^{2+}\), pH 2.5) & -Fe\({}^{2+}\) reduced from too to 10 mg/L \\  & Membrane: Bipolar (Pumasegr\({}^{2}\)) & REM & -Current density: 1.2 A/m\({}^{2}\) & \\ \hline  & System: Dual-chamber MFC & Analytic Synthetic wastewater with & \\  & Anode: Carbon felt (6 mm thick, 3 \(\times\) 3 cm\({}^{2}\)) & acetate (pH 7) & -9\% Cu recovery in & \\  & Cathode: Stainless steel with Polypyrrole & Catholyte: CuSO\({}_{4}\) solution (256 mg/L & 3 days—SS/PPy-PA cathode: higher \\  & (SS/PPy-PA), Polypyrrole with Carbonised & Cu) in 25 NaCl PHi 5.30 & efficiency but corroded over time & [70] \\  & Cellulose (SS/PPy-CC), and combinations & Temperature: 30 \({}^{\circ}\) C & -SS/PPy suitable for large-scale & \\  & (SS/PPy-PA-CC) & Rest: Various (10–20,000 f\(\Omega\)) & MFCs & \\ \hline  & System: Photosynthetic dual-chamber MFC & & -Cu\({}^{2+}\) recovery: 94\% & \\  & Anode: Carbon felt (CF) (110 cm\({}^{2}\)) & Cathode: 125 mL cultivated algae & -Co\({}^{2+}\) recovery: 88\% & \\  & Cathode: CF (130 cm\({}^{2}\)), CF coated with & & (pH 7) & -Co\({}^{2+}\) recovery: 88\% & \\  & & Cu-accumulated ABC700 (activated blocker 400 mL with Cu\({}^{2+}\) or Co\({}^{2+}\)) & -Fe\({}^{2+}\) removal achieved with & \\  & & prepared from algae biomass thermally & (25, 50, 75, and 100 mg/L, pH 7) & Co-accumulated ABC700 cathode & \\  & activated at 700 \({}^{\circ}\)C), and CF coated with & Rest: 100 \(\Omega\) & -Algal biochar cathodes contributed & \\  & & Membrane: Clayware cylinder wall as proton & Temperature: Room temperature & to reducing pollutants and \\  & exchange separator & & supporting energy generation & \\ \hline  & System: Dual-chamber \({}^{2}\)H\({}^{+}\)-Type MFC & Analytic: Acetate and glucose-based & -99\% Sb removal with MnCoPy-MFC & \\  & Anode: Carbon felt (CF), Carbon nanofibers & medium & -Maximum power density hierarchy: \\  & energy recovery using & (CNF), MnCo/CNF, MnCo/CNF with pyrite & Catholyte: 25 mM K\({}_{3}\)[Fe(CN)]\({}_{6}\) & CF-MFC \(<\) CNF-MFC \(<\) \\  & pyrite-enhanced MnCo/CNF & (5 \(\times\) 2 cm) & -Solution & MnCoCNF-MFC \(<\) MnCoPy-MFC \\ anode & Cathode: Carbon felt (5 \(\times\) 2 cm) & Rest: 1000 \(\Omega\) & -MnCoPy-MFC exhibited the highest & \\  & Membrane: Nanofiber membrane & Temperature: 20 \(\pm\) 5 \({}^{\circ}\)C & energy recovery performance & \\ \hline \end{tabular}
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Table 2: Key studies highlighting advances in metal recovery using BES. \begin{table}
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**Objective** & **Reactor Setup** & **Operational Conditions** & **Milestones** & **Ref. ** \\ \hline  & & & -97.7\% Cr(VI) removal with optimal & \\  & System: Upflow MFC & Anolyte: Mineral medium (pH 7), 800 mg/L influent, 2-day retention & \\ Cr\({}^{th}\) recovery using upflow & Anode: Carbon left with granular activated & 0.98 L & time, and pH 7 (anode)/pH & \\ Cr\({}^{th}\) recovery using upflow & Carbon (45 g, 377 cm\({}^{2}\)) & Catholyte: Cr(VI)-containing medium & 4 (carbode). & \\ MFC & Cathode: Carbon cloth (1130 cm\({}^{2}\)) & (pH 4), 4.2 L & -Cr(III) precipitation reduced MFC & [72] \\  & Membrane: Proton exchange (Nafón\({}^{th}\) 117) & Temperature: 34 °C & efficiency over time.