Abstract
In this paper, the adsorption process of a pharmaceutical compound (tetracycline: TC) on a biochar was theoretically analyzed. The adsorbent was activated via two different methods (impregnation method and dry mixing method). The adsorption mechanism of TC was understood through an analysis of double-layer model parameters, suggesting that the adsorption of TC can be achieved via formation of two layers on both adsorbents. This modeling showed that this aggregation process was present and absent for the adsorption systems TC–biochar impregnation method (BCI) and TC–biochar dry mixing method (BCD), respectively. Comparatively, it was demonstrated that both adsorbents were characterized by excellent adsorption capacities and they can be alternatives to remove TC. The interactions between TC–BCD, TC–BCI, and TC–TC were estimated by an adsorption energy calculation at different temperatures. Overall, the interpretation of the model parameters provided plausible insights into the adsorption mechanism.