## 2 Methods of Eliminating Hormones and Pharmaceuticals
### Physical Methods
#### 2.1.2 Ultrafiltration  
Ultrafiltration (UF) is a pressureised membrane process that uses membranes with pores in the range of 0.01-0.1 \(\upmu\)m. This technology effectively removes suspended solids, colloidal particles, bacteria, and some organic macromolecules. [PERSON] et al. [67] investigated two types of UF-GE and UF-CNT membranes and estimated the retention rate of micropollutants removed from the deionised water solution for the mentioned membranes. For BPA, E2, and EE2, higher removal rates were obtained for the nanotube-modified ultrafiltration membrane than for the commercial membrane. The retention rate of BPA is 5% for the UF-GE membrane and 48% for UF-CNT. For E2 and EE2, the difference in retention between the membranes mentioned above is about 5%. The micropollutant removal efficiency of these membranes depends on their different physicochemical properties. The UF-CNT membrane shows good adsorption properties and has higher porosity with carbon nanotubes. In [67], the effect of carbon nanotubes on membrane hydraulic performance was documented while maintaining a high retention rate of micropollutants. It was also shown that, regardless of the type of membrane used, EE2 was removed at a higher rate compared to the other two micropollutants [67; 68]. EE2 has a higher affinity for membrane-forming polymers compared to E2 or BPA due to the higher value of its characteristic partition coefficient between the n-octanol phase and water (logK\({}_{\text{ow}}\) mol\(\cdot\)dm\({}^{-3}\)). The higher the logK\({}_{\text{ow}}\) value, the more hydrophobic the substance is and the greater its tendency to adsorb to the membrane surface. It was demonstrated in [69] that the mechanism of separation of hydrophobic compounds on the membrane is a two-step process, i.e., in the first step, the chemical substance is adsorbed on the surface of the membrane, and in the second step, it passes through the membrane \begin{table}
\begin{tabular}{c c c c c} \hline
**MOF Material** & **Target Compounds** & **Adsorption Mechanisms** & **Removal Efficiency [\%]** & **Ref.** \\ \hline MIL-101-NH\({}_{2}\) & E2, EE2, E1, mifeprstone, other EDCs & \begin{tabular}{c} Hydrogen bonding, \(\pi\)-\(\pi\) \\ interactions, van der \\ Waals forces \\ \end{tabular} & 85–95\% & [62] \\ \hline MIL-101(Cr) + urea/melamine & Metronidazolezole, tinidazole, ornidazole & \begin{tabular}{c} Hydrogen bonding, electrostatic \\ interactions, enhanced porosity \\ \end{tabular} & 91–97\% & [63] \\ \hline Ce-DUT-52 & Oestradiol, E1, heexstrol & \begin{tabular}{c} Electrostatic interactions, \\ positive zeta potential \\ \end{tabular} & 82–90\% & [64] \\ \hline Zr/Fe-MOFs/GO & Tetracycline, orange II dye & \begin{tabular}{c} \(\pi\)-\(\pi\) interactions, electrostatic \\ attraction, high surface area \\ \end{tabular} & 96–99\% & [65] \\ \hline UiO-66 and derivatives & Ibuprofen, naproxen, diclofenac & \begin{tabular}{c} Hydrophobic interactions, \\ metal–ligand coordination, \\ hydrogen bonding \\ \end{tabular} & 80–93\% & [66] \\ \hline ZIF-8 & \
\begin{tabular}{c} Sulfamethoxazole, \\ carbamazepine \\ \end{tabular} &
\begin{tabular}{c} Molecular sieving effect, \\ hydrophobic pore interactions \\ \end{tabular} & 75–88\% & [66] \\ \hline \end{tabular}
\end{table} 
Table 3: Effect of MOF material type on elimination of hormones and pharmaceuticals from wastewater; authors’ own elaboration based on [62; 63; 64; 65; 66]. by diffusion. The value of the logKow parameter for EE2 is 4.15 mol\(\cdot\)dm\({}^{-3}\), that for E2 is 4.01 mol\(\cdot\)dm\({}^{-3}\), and that for BPA is 3.32 mol\(\cdot\)dm\({}^{-3}\), respectively. Furthermore, the molar mass of EE2 is higher than that of E2 and BPA, which also explains the higher retention of EE2 in the membrane compared to other micropollutants. The retention rates for EE2, E2, and BPA when filtering model effluent showed a similar trend as when filtering the deionised water solution [67; 68; 70]. EE2 was removed the most, while BPA was removed to the lowest extent (Table 4).