Adsorption characteristics of antibiotics trimethoprim on powdered and granular activated carbon

The adsorption characteristics of trimethoprim (TMP) onto powdered activated carbon (PAC) and granular activated carbon (GAC) were studied. The adsorption isotherms could be plotted using the Langmuir, Freundlich and Toth models with a reasonable degree of accuracy. Toth isotherm model was better for describing the adsorption equilibrium than Freundlich model, even though the Langmuir model also agreed with the experimental data well. It shows that the Toth model is adequate for fitting equilibrium data for adsorption of TMP on both PAC and GAC in this study. Fixed-bed breakthrough curves were studied under various operating conditions. The performances of the fixed-bed GAC system was also simulated by a model developed with homogeneous surface diffusion model (HSDM).