Adsorption of aqueous rare earth elements using carbon black derived from recycled tires

The adsorption of an aqueous mixture of light rare earth elements (Y, La, Ce, Nd, and Sm) by carbon black derived from pyrolyzed end-of-life tires was investigated. The recycled tire carbon black (RTCB) was compared with other commercial carbon and functionalized carbon sorbent materials. The RTCB demonstrated improved adsorption for all the rare earth elements in this investigation over other carbon sorbent materials under a variety of conditions. The adsorption isotherms were observed to follow the Freundlich model with pseudo-second order kinetics. Analysis of thermodynamic state functions suggests the adsorption to be endothermic, energetically favorable under the conditions of study, and a dissociative adsorption mechanism. The use of RTCB as a sorbent material for extraction of aqueous REEs is attractive due to its inexpensive cost and utilization of a recycled material stream.