## 3 Results and Discussion
### Sorption Abilities Tests
#### 3.4.2 The Pharmaceuticals Sorption
Summing up the considerations regarding paracetamol sorption on the polymers under study, it should be emphasized that the mechanism of the process should take into account not only the Van der Waals and \(\pi\)-interactions but also the possibility of donor-acceptor or hydrogen bond formation. The ibuprofen recoveries on the studied polymers reached the highest values among all the tested pharmaceuticals. Similarly to the previously discussed adsorbates, for ibuprofen, the influence of the polymer's porosity development on the obtained recovery values was also the most pronounced. For the terpene-based polymers, the positive effect of the presence of surface acidic functionalities should also be mentioned because the recoveries for C-DVB were almost twice as much as that for L-DVB. However, such a relationship was not observed for the pair of oil-based polymers, both for ibuprofen and chlorophenols. Recoveries for Lo-DVB in all cases were ca 50% lower than for the other considered polymers. A comparative analysis of all the collected data allowed for the identification of some analogies to the recovery values obtained for the 100 mL samples of 2,4,6-TChP or 2,4-DChP. Specifically, 2,4,6-trichlorophenol had chemical properties (log P, s water, and to a lesser extent pKa) similar to those of ibuprofen. This suggests that the ibuprofen sorption process might follow the same mechanism as for chlorophenols. The presence of an aromatic ring and alkyl or halogen substituents in the molecules of these adsorbates caused by the uptake on the polymer surface was based on not very strong physical interactions including hydrophobic, Van der Waals, and aromatic \(\pi\)-electron interactions. However, the presence of OH or COOH groups with a strong negative potential in the molecule additionally led to specific interactions, such as hydrogen bonding and the formation of the donor-acceptor complexes, which contributed to the sorption process, favoring or countering it, depending on the properties of the environment and the adsorbent. Therefore, when comparing the sorption of the same compound on different polymers, the reasons for the different sorption results should be sought in the structure and surface chemistry of these materials. The highest value of AV for Lo-DVB indicated that the concentration of acidic functional groups on its surface was high. This dissociation of mainly carboxylic moieties not only changed the acid-base balance of the solution but also left the polymer surface negatively charged, which was not beneficial for the sorption of molecules with a negative potential accumulated around their carboxyl, hydroxyl, or halogen groups. Such repulsive electrostatic interactions tended to move away or repel the negatively charged side of the molecule from the polymer surface, which in turn reduced the interaction of the adsorbate with the sorbent; this is schematically presented in Figure 11 and in the form of a simple animation submitted as a Supplementary File (Video S1). Figure 11: Scheme of possible acid-base balance between an ibuprofen molecule and acid moieties of the polymer. Table 7 shows the comparative recovery results of drugs that were obtained for different types of sorbents. It can be seen that the data varied greatly and depended both on the type of sorbent and the elution conditions. Higher results were obtained for sorbents modified with specific functional groups, the presence of which enhanced the interactions with drug moieties; in other cases, the results were lower. Taking into account the results presented in this work it should be stated that ibuprofen recovery for C-DVB is comparable and the recovery of salicylic acid is even higher than those reported in the literature. The sorption ability tests presented above showed that the prepared bio-based polymers containing natural origin components in their structure can be used to effectively remove selected phenolic and pharmaceutical compounds from aqueous solutions.