Sorption kinetics of anionic surfactant on to waste tire rubber granules

The efficiency of a locally available very low cost waste tire rubber granule in removing anionic surfactant (AS) by adsorption process was evaluated. As a representative member of AS sodium dodecyl sulfate (abbreviated as SDS) was used. It was found that in the batch experiment conducted at 2.0 mg/l initial concentration of SDS, rubber granules could remove up to 92% of SDS from wastewater. Kinetic profiles under various conditions were developed. The equilibrium time was found to be 6 h. Reaction rate constants (forward, reverse and overall) were determined for different initial concentrations of SDS by approximating the kinetic data to the first-order reversible kinetic model. Pore and film diffusion coefficients were determined from the half-time equations and film diffusion appeared to be rate limiting. This was further supported by multiple interruption tests.