Leaching of toluene-neoprene adhesive wastes

This work consists of the study of the extraction of solvent (toluene) from a polymeric (neoprene) substrate during a leaching process. Total organic carbon (TOC) is the main contaminant parameter in the leaching of these sys tems due to the solution of the toluene and the dispersion of the polymer. The toxicity of the extracts was measured with a Microtox equipment, using Photobacteria phosphoreum, deducing that the toxicity of the extracts is du e to the low solubility of toluene but that the toxicity of toluene is high . On the basis of the experimental results; the amount of toluene diffused vs time in plane sheet systems was studied. Akinetic model has been develop ed considering two stages. In the first stage, the toluene diffuses into th e system across the neoprene chains at a constant rate, not depending on th e initial toluene. concentration. This fact is explained by considering tha t there is a constant difference of the toluene concentration between the i nterface with the water and the inner part of the sample. In the second sta ge, the dispersion of the polymer with the corresponding amount of toluene takes place. The diffusion of toluene in the leaching process is compared a nd analyzed considering the diffusion of toluene in a:desorption process in air so that the difference of toluene concentration between the interface and the interior can be estimated. A mathematical model is also proposed fo r considering the leaching process in other operating conditions.