## 2 Materials and Methods
### Batch Adsorption Test
#### 3.4.2 Kinetic Studies  
When evaluating the amount of AO dye retained by the synthesized adsorbents, an extremely important step in the study was the selection of process conditions, i.e., phase contact time. In the kinetic adsorption tests carried out, the range of the tested parameters varied from 1 min to 240 min for two different concentrations of AO (10 and 100 mg/L) in solution. Figure 8 shows a graphical interpretation of the \(q_{t}\) vs. t, confirming the high affinity of AO for poly(DVB), DVB-VBCI, poly(EGDMA) and EGDMA-VBCl. The result is the almost immediate establishment of the adsorption equilibrium in the studied systems. After 10 min of phase contact time, the amount of AO taken up by the polymer microspheres reached maximum values. Slightly bigger \(q_{t}\) values were obtained for DVB-VBCI and EGDMA-VBCl adsorbents. The amount of adsorbed AO by EGDMA-based sorbents is insignificantly greater than that of DVB-based sorbents, which may be due to the more hydrophilicity of the former.  
Comparing the results obtained with the data available in the literature, it should be noted that the optimal phase contact time of the adsorption process is strongly determined  
Figure 8: Time impact on AO uptake from the solutions of initial concentrations 10 mg/L and 100 mg/L by (**a**) poly(DVB) and DVB-VBCl as well as (**b**) poly(EGDMA) and EGDMA-VBCl.  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Adsorbent** & **Equilibrium Data** & **Ref.** \\ \hline \multirow{2}{*}{Clay mineral from Turkey} & Langmuir model: & \\  & \(q_{e}\) = 833.3-714.28 mg/g at 25–45 \({}^{\circ}\)C & [23] \\ \hline \multirow{2}{*}{Bagasse fly ash} & Langmuir model: & \\  & Langmuir model: & \\ \hline \multirow{2}{*}{Mesoporous carbons} & Langmuir model: & \\  & \(q_{e}\) = 175–360 mg/g at 30–60 \({}^{\circ}\)C & [25] \\ \hline \multirow{2}{*}{C/SiO\({}_{2}\) composite} & Freundlich model: & \(k_{\rm F}\) = 27.37–55.41 mg\({}^{1-1/n}\) L\({}^{1/n}\)/g T = 20–60 \({}^{\circ}\)C, & [26] \\  & Freundlich model: & \(k_{\rm F}\) = 11.1–45.7 mg\({}^{1-1/n}\) L\({}^{1/n}\)/g & [27] \\  & & at 20–60 \({}^{\circ}\)C & [28] \\ \hline \multirow{2}{*}{Modified globe _Artichoke_ leaves} & [PERSON] model: & \\  & & \\ \hline poly(DVB), DVB-VBCI, poly(EGDMA), & [PERSON] model: & \(k_{\rm F}\) = 4.56–7.85 mg\({}^{1-1/n}\) L\({}^{1/n}\)/g & \\  & EGDMA-VBCl & at 25 \({}^{\circ}\)C & This study \\ \hline \hline \end{tabular}
\end{table}
Table 3: Removal of auramine O by different adsorbents based on the literature review.  
by the type of adsorbent used. For example, the time necessary to reach equilibrium in the solutions containing AO in the amount of 50 mg/L using the EGDMA + DVB + TEVS + ZrO\({}_{2}\)-SiO\({}_{2}\) + lignin based adsorbents was found to be 180 min. After 1 min of phase contact time, about 81.1-85.7% of AO was removed by EGDMA + DVB + TEVS + ZrO\({}_{2}\) - SiO\({}_{2}\) + lignin based adsorbents [27]. According to [PERSON] et al. [29] investigating AO retention (500 mg/L) using epichlorohydrin and tripolyphosphate-crosslinked chitosan-kaolin composite by after the 6 h, an equilibrium plateau was reached and maintained until the 24 h. During AO (100 mg/L) sorption experiments on _Ipomoa aquatica_ roots as ecofriendly adsorbent, 120 min was sufficient for the system to reach equilibrium [30]. [PERSON] et al. [31] reported that 3 h was enough to obtain the equilibrium during AO (50-200 mg/L) sorption on the sesame leaf as a biosorbent.