Investigation of effective parameters on adsorption of amoxicillin from aqueous medium onto activated carbon

In this study, the adsorption of amoxicillin onto activated carbon was investigated. The effect of particle size and the effluent flow rate was discussed as well as the kinetics and isotherm of adsorption equilibrium. The isotherm equilibrium studies showed that the Langmuir model was appropriate for describing the adsorption equilibrium of amoxicillin onto the activated carbon. Furthermore, the kinetics of adsorption fit the pseudo-second-order model while the highest adsorption amount occurred at pH = 5. Moreover, the change of particle size from 600 microns to 125 microns resulted in increasing the adsorption amount of 102 mg.g-1 to 225 mg.g-1. Furthermore, the breakthrough curves indicated that the controlling mechanism of mass transfer was intra-particle diffusion. Also, by reducing the length of the bed from 6.8 to 3.4 cm, the breakpoint time decreased from 3.2 hours to 54 minutes at 300 ppm initial concentration. Eventually, the breakpoint time increased from 2 minutes to 55 minutes by decreasing the average particle diameter from 840 to 250 microns.