## 3 Results and Discussion
### Fixed-Bed Column Adsorption Evaluation  
Similar to batch adsorption, Table 5 presents the experimental conditions and results obtained for each run in the fixed-bed column experiments. The breakthrough curves for each run can be viewed in Figure S2 (Supplementary Material). The findings indicate that the highest maximum adsorption capacities for both pharmaceuticals (qmaxPAR = 49.49 mg/g and qmaxMTZ = 43.64 mg/g) were achieved in Experiment 1 (C0 = 30 mg/L; Q = 5 mL/min; W = 0.50 g). To identify the optimal operational conditions, the simultaneous adsorption of the pharmaceuticals was analyzed. As shown in Table 5, most runs exhibited similar behavior, with values of maximum adsorption capacity in comparable orders of magnitude. Additionally, in many cases, the adsorption of paracetamol was slightly favored, resulting in a higher qmax compared to metronidazoleole. This suggests a stronger interaction between the carbon activated and paracetamol. [PERSON] et al. [59] studied the removal of paracetamol, metronidazoleole, and diclofenac using carbon-polymeric membranes, finding that diclofenac removal reached 44%, while paracetamol and metronidazoleole had removal rates of 4% and 8%, respectively. These differences can be attributed to variations in molecular weight and solubility among the compounds. The authors also noted that the removal efficiency varied according to the \begin{table}
\begin{tabular}{c c c c c c} \hline \hline \multirow{2}{*}{**Run Order**} & \multicolumn{3}{c}{**Independent Variables**} & \multicolumn{3}{c}{**Response**} \\ \cline{2-6}  & **C0 (mg/L)** & **W (g)** & **Q (mL/min)** & **qmaxPAR (mg/g)** & **qmaxMTZ (mg/g)** \\ \hline
1 * & 30 & 0.50 & 5 & 49.49 & 43.64 \\
2 & 30 & 0.50 & 15 & 6.54 & 5.36 \\
3 & 30 & 1.00 & 5 & 10.85 & 10.66 \\
4 & 30 & 1.00 & 15 & 32.54 & 9.01 \\
5 & 50 & 0.50 & 5 & 2.46 & 4.86 \\
6 & 50 & 0.50 & 15 & 14.59 & 8.22 \\
7 & 50 & 1.00 & 5 & 6.55 & 4.33 \\
8 & 50 & 1.00 & 15 & 6.45 & 11.25 \\
9 * & 40 & 0.75 & 10 & 3.11 & 2.42 \\
10 * & 40 & 0.75 & 10 & 3.72 & 10.21 \\
11 * & 40 & 0.75 & 10 & 10.21 & 15.92 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Experimental matrix and responses for simultaneous adsorption of pharmaceuticals in a fixed-bed column. concentrations of the compounds applied in the process, particularly for paracetamol and metronidazoleze, a trend observed in the present study as well. Additionally, they found that incorporating activated carbon into the membranes significantly increased removal rates by 34% for paracetamol and 28% for metronidazoleze, helping to explain the higher values recorded in this work. [PERSON] et al. [60] compared three removal methods for metronidazoleze and paracetamol in a batch process, observing that photocatalysis had a significant impact on the photodegradation of both compounds, while adsorption and photolysis were less effective. This indicates that achieving effective adsorption of these compounds can be challenging using this method. However, the present study achieved high adsorption efficiencies with continuous adsorption, recording q\({}_{\text{max}}\) values of 49.49 mg/g for paracetamol and 43.64 mg/g for metronidazoleze. Comparing the results with the adsorption of only PAR in batch process, also using GAC, by [PERSON] et al. [61], the authors obtained q\({}_{\text{maxPAR}}\) = 31.5 mg/g, and [PERSON] et al. [62] evaluated the adsorption of specific pharmaceuticals (paracetamol, carbamazepine, metronidazoleze, and caffeine) in a single and batch approach and observed that the removal capacity for PAR ranged between 0.071 and 0.434 mg/g, while for MTZ it was 0.11 to 0.539 mg/g using different activated carbon materials, showing a high efficiency of removal rate in this study when applying the continuous adsorption, an industrial approach, even in a multi-compound system.