Hey! Author from the paper here. The volume of water is dependent on the mass of adsorbent used and the concentration of Pb or other metal in the water. The m

Hey! Author from the paper here. The volume of water is dependent on the mass of adsorbent used and the concentration of Pb or other metal in the water. The mg/g values given in a few of the figures/tables for each of the nanomaterial-coated sponges gives the mass of Pb per mass of adsorbent that is the "maximum capacity" for the given adsorbent. So, if there's a 20mg/g capacity, that would imply 1 gram of sponge can remediate 20mg of metal ion in water, which would be, say, 20 Liters of water at 1ppm concentration of the metal ion. It was slightly outside the scope of our research to discuss utilization of that metal ion, but it is a mostly solved engineering problem. Ideally, the sponge would be regenerated after it was full/at capacity with a metal like Co, with a small volume of water, to generate a high concentration solution of Cobalt, which could then be precipitated out as a metal or Cobalt salt using a strong base, or utilized in applications that require Cobalt in solution, or, with certain metals, incorporated into another mineral straight from solution for use in, say, a battery cathode or other material.