Adsorption of Toluene by Waste Tyre Rubber Granules: Effect of Operating Variables, Kinetic and Isotherm Studies

Waste tyre rubber granules (WTRG) were used to adsorb toluene from aqueous solutions. Their sorption capacities were determined by testing the effect of variables such as contact time, initial concentration of toluene, amount of adsorbent, size of adsorbent particles, and temperature of solution. The adsorption of toluene by WTRG was relatively fast (equilibrium time of 30 min). Increasing the dosage of WTRG and the concentration of toluene in solution resulted in an increase in the adsorption capacity of WTRG. The adsorption capacity of WTRG decreased from 18.12 to 13.32 mg/g with increase in particle size from 0.212 to 2.36 mm while an increase in the temperature from 5 to 40 °C resulted in a decrease in the adsorption capacity from 17.57 to 16.26 mg/g. The adsorption of toluene was best described by the Lagergren pseudo-first order kinetic equation and Langmuir isotherm equation. This study has shown that WTRG can be used for the adsorption of toluene from aqueous solutions.