## 2 Materials and Methods
### Adsorption Experiments  
Adsorption experiments were done under batch operation conditions. For each pharmaceutical, adsorption kinetic experiments were first carried out in order to determine the time necessary to attain equilibria (\(t_{\text{eq}}\)). Next, equilibrium experiments were done to determine the corresponding adsorption isotherm. All experiments were carried out by shaking (250 rpm) a known mass of adsorbent (Sepabeads SP207 or GPP20) together with 100 mL of ultrapure or waste water in 250 mL Erlenmeyer flasks. Initial concentration of each target pharmaceutical in waste water was 100 \(\pm\) 1 mg L\({}^{-1}\). All experiments were done in triplicate and at a constant temperature of 25 \(\pm\) 2 \({}^{\circ}\)C, provided by a thermostatically regulated shaker. Triplicate controls, which consisted of solutions of the corresponding pharmaceutical (100 \(\pm\) 1 mg L\({}^{-1}\)) in the absence of adsorbent, were run in parallel with adsorption experiments.  
In the kinetic experiments, Erlenmeyer flasks were progressively withdrawn from the shaker after pre-set time intervals. Then, from each flask, three aliquots were taken, filtered, and chromatographically analyzed to determine the concentration of the target pharmaceutical. For each of the pharmaceuticals here considered (acetaminophen and ibuprofen), the adsorbed concentration onto each adsorbent at any time, \(q_{\text{t}}\) (mg g\({}^{-1}\)), was calculated by the following mass balance relationship (Equation (1)):  
\[q_{\text{t}}=(C_{0}-C_{\text{t}})\frac{V}{W} \tag{1}\]  
where C\({}_{\text{t}}\) (mg L\({}^{-1}\)) is the experimental liquid-phase concentration of pharmaceutical at a time t, C\({}_{0}\) (mg L\({}^{-1}\)) is the average concentration of pharmaceutical in the corresponding control, \(V\) is the volume of the solution (L), and \(W\) is the mass (g) of adsorbent.  
For equilibrium experiments, Erlenmeyer flasks containing the target pharmaceutical solution together with the corresponding adsorbent were under shaking during the \(t_{\text{eq}}\). Then, from each flask, three aliquots were withdrawn, filtered and chromatographically analyzed to determine the pharmaceutical equilibrium concentration (C\({}_{\text{e}}\), mg L\({}^{-1}\)) in the liquid phase. Then, the equilibrium adsorbed concentration of pharmaceutical onto the corresponding adsorbent, \(q_{\text{e}}\) (mg g\({}^{-1}\)), was calculated by the mass balance relationship displayed in Equation (2):  
\[q_{\text{e}}=(C_{0}-C_{\text{e}})\frac{V}{W} \tag{2}\]  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline \multirow{2}{*}{pH} & **Conductivity** & **TSS** & **BOD5** & **COD** & **NTK** & **N-NH4** & **N-NO3** & **N-NO2** & **Total P-PO4** \\ \cline{2-10}  & **(μs cm\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** & **(mg L\({}^{-1}\))** \\ \hline
7.8 \(\pm\) 0.2 & 612 \(\pm\) 3 & 22 \(\pm\) 1 & 21 \(\pm\) 2 & 47 \(\pm\) 3 & 17 \(\pm\) 2 & 13.0 \(\pm\) 0.42 & 1.73 \(\pm\) 0.18 & 0.48 \(\pm\) 0.09 & 1.75 \(\pm\) 0.13 \\  & 35\({}^{\circ}\) & 25\({}^{\circ}\) & 125\({}^{\circ}\) & & & & & & \\ \hline \hline \end{tabular}  
* * Limits for discharge according to the Urban Waste Water Directive (Council Directive 91/271/EC of 21 May 1991 concerning urban waste water treatment as amended by Commission Directive 98/15/EC and Regulations 1882/2003/EC and 1137/2008/EC).  
\end{table}
Table 3: Main properties of the urban WWTP effluent used in this work.  
where \(\rm C_{e}\) (mg L\({}^{-1}\)) is the experimental equilibrium liquid-phase concentration of pharmaceutical.