Removal of aspirin and tetracycline hydrochloride using UiO66/Polydopamine/bacterial cellulose composite:...

The effective removal of antibiotics and non-steroidal anti-inflammatory drugs and their combined pollutants is critical for both the aquatic environment and human health. This study evaluates the removal of pharmaceutical waste through the adsorption of aspirin and tetracycline hydrochloride (TC) onto the surface of a UiO-66/Polydopamine/Bacterial Cellulose composite (UiO-66/PDA/BC). Both theoretical and experimental approaches were considered to investigate the removal of aspirin and TC. The theoretical study, based on statistical physics theory, employs three analytical models to describe the adsorption phenomena of these drugs at the molecular level. According to the fitting results, the adsorption of both drugs onto the UiO-66/PDA/BC composite is an endothermic process and follows a monolayer adsorption mechanism with one type of site. Regarding the number of adsorbed molecules per site (n), the analysis indicates that both multi-docking (n < 1) and multi-molecular (n > 1) adsorption mechanisms are possible for aspirin and TC on UiO-66/PDA/BC. The adsorption capacities at saturation of the UiO-66/PDA/BC adsorbent deduced by the monolayer model are found to be 147.34-215.05 mg/g for aspirin and 193.72-246.66 mg/g for TC. Furthermore, adsorption energy calculations suggest that the removal of these pharmaceutical pollutants occurs primarily through physical interactions. The thermodynamic analysis confirms the spontaneous and feasible nature of the adsorption of both drugs onto the UiO-66/PDA/BC composite.