Sorption of Organic Compounds in the Aqueous Phase onto Tire Rubber

Batch sorption tests were conducted to investigate the sorption capacity of organic compounds by ground tire and to assess the effects of the presence of other organic compounds, ionic strength, pH, ground tire particle size, and temperature on sorption. None of the factors were significant under the conditions tested. m-Xylene had the highest partition coefficient (977 L/kg), followed by ethylbenzene, toluene, trichloroethylene, 1,1,1-trichloroethane, chloroform, and methylene chloride (13 L/kg). The partition coefficients had a logarithmic linear relationship with the octanol-water partition coefficients. The diffusion coefficients of the compounds tested were in the range of 10−8 cm2/s. The diffusion coefficients did not correlate well with the physical/chemical properties, such as molecular size, of the compounds tested. The heat of solutions of the compounds tested had relatively low values (<2.5 kJ/mol/K). Thus, the sorption may not be affected significantly by temperature change. Organic compounds sorbed onto tire rubber appear to be sorbed primarily onto tire rubber polymeric materials and partially carbon black in the tire rubber. Overall, ground tire shows significant capacity as a sorbent of organic compounds.