Adsorption of Pharmaceutical Formulations onto Non-Conventional Biocarbons

This study investigated the adsorption of pharmaceutical formulations (aspirin, enantyum, ibuprofen, metamizol, nolotil, paracetamol, and termalgin) and simultaneous binary mixtures of them onto activated carbons derived from olive stone (OSPC) and pine nut shell (PNSPC). Both biocarbons exhibited superior properties without prior washing, exhibiting the highest adsorption capacity (45 mg/g) with 1.0 g OSPC/L and 50 mg ENA/L at pH 2. FTIR analysis identified oxygenated and phosphate-related surface groups in both carbons, with OSPC exhibiting stronger functionalization, and revealed minimal differences in adsorption between commercial formulations and pure active ingredients. Raman spectroscopy showed small increases in the ID/IG ratio after adsorption, attributed to slight increases in defect density, without significantly altering the carbon structure. SEM analysis revealed that OSPC exhibited a more heterogeneous and porous structure than PNSPC, consistent with its larger BET surface area. The presence of surface phosphate groups was detected using XRD, and they were found to be more pronounced in OSPC; this was attributed to the fact that the adsorbents were not washed beforehand. Finally, OSPC was used to adsorb each of the six drugs independently in 14–15 consecutive cycles, with removal efficiency exceeding 85%; thus, its use could be considered in the treatment of wastewater containing the drugs from this study, in line with the circular economy, which aims to achieve zero waste.