Performance Evaluation of Physically Activated PET Fibers for Antibiotic Adsorption in Aqueous Solution

This study examines the potential of physically activated PET fibers (PA-PET) as an adsorbent for adsorption of two antibiotics (rifampicin (RIF) and rifaximin (RIX)) from aqueous solution. To evaluate the performance of PA-PET, the effects of the initial antibiotic concentration and the contact time were experimentally investigated at pH 2.0 and an adsorbent dosage of 0.4 g/L. While no notable differences were observed regarding the contact time, equilibrium being reached after 180 min, similar to raw PET fibers, a significant increase in adsorption capacity was recorded across the entire range of initial antibiotic concentrations. The highest increases in adsorption capacity were obtained at RIF concentrations of 68 mg/L, where the adsorption capacity increased by more than 107%, and at RIX concentrations of 4.28 mg/L, where the increase reached approximately 84%, compared with the raw PET fibers. To further highlight the performance of PA-PET in the adsorption of RIF and RIX, the isotherm and kinetic data were modeled. Desorption of RIF and RIX from PA-PET was carried out using a medical-grade polyelectrolyte solution (SL) as the desorbing agent. Although the desorption efficiency is relatively modest (below 33% for RIF and 26% for RIX, after 360 min), the molecular structure of RIF and RIX does not change after desorption, and antibiotics can be reintroduced into the technological circuit. These results demonstrate that PA-PET is as a promising, low-cost, and efficient adsorbent for antibiotic removal, offering a practical solution for pollution reduction and more sustainable waste management.