USE OF A GEL-FORMING BIOPOLYMER DIRECTLY DISPENSED INTO A LOOP FLUIDIZED-BED REACTOR TO RECOVER DISSOLVED COPPER

A novel technique for the recovery of copper from synthetic aqueous solutions containing 60-200 ppm dissolved copper was developed in this work. A viscous solution of sodium alginate (a kelp-derived biopolymer known to bind copper) was dispensed dropwise by using a multi-tip dispenser into the synthetic solution circulating in an air-lift glass loop fluidized bed reactor. Upon contact with the copper-containing solution, the alginate gelled into stable spheres which continued to circulate in the reactor to absorb copper. The percent of copper recovered at the lower ionic strength (0.01 M NaNO3) was found to be greater than that at the higher ionic strength (0.1 M NaNO3) of the solution. (Consequently, the conditional copper-binding stability constant for the former case was greater.) An intrinsic copper-binding stability constant, independent of the ionic strength of the solution, was obtained by using a two-phase model modified from our recent work (Jang et al., J. Polymer Sci., Part B 27, 1301-1315, 1989; J. phys. Chem. 94, 482-488, 1990c). © 1990.