Reactors and methods for producing and recovering extracellular metal or metalloid nanoparticles

A bioelectrochemical reactor system for production of extracellular metal and metalloid nanoparticles, comprising:

• a bioelectrochemical reactor comprising:
• an anode chamber which comprises a bacteria-coated anode;
• a cathode chamber which comprises a bacteria-coated cathode;
• a cation exchange membrane in fluid communication with, and separating, the anode chamber and the cathode chamber;
• a source of an electron donor substance configured for supplying the electron donor substance into the anode chamber;
• a source of metal ion-contaminated medium configured to pump the medium through the cathode chamber;
• and
• an external resistor in a circuit with the anode and the cathode,
• wherein the bioelectrochemical reactor is configured to operate anaerobically and reduce the metal or metalloid ions in the metal or metalloid ion-contaminated medium to extracellular metal or metalloid nanoparticles.

A device for separating extracellular metal or metalloid nanoparticles from biomass components comprising:

• a vertically elongated vessel which comprises an inlet about an upper end of the vessel for receiving a medium comprising a mixture of bacteria and extracellular metal or metalloid nanoparticles, an outlet for discharge of the medium from the vessel about the upper end of the vessel opposite the inlet, and an outlet about the lower end of the vessel for discharge of biomass from the vessel;
• and
• a plate comprising a plurality of pores to permit the passage of water but not the passage of the nanoparticles or bacteria agglomerates,
• wherein the plate is disposed within the vessel at an angle relative to flow of the medium through the vessel such the bacteria will agglomerate and roll off of the plate and the nanoparticles will adhere to the plate.