## 2 Results
### Auxiliaries Presence on Dye Adsorption Effectiveness  
The assessment of the influence of additives (called auxiliaries in the chemical processing of textiles) present in dyeing baths and textile effluents on the effectiveness of dye retention is an extremely important part of the experiments. Auxiliaries are used in large amounts to facilitate the binding of dyes to the fabric and they get into the sewage in the amounts used for dyeing, significantly modifying the composition of the sewage. On the basis of [10], the amounts of the additives such as acids, salts and surfactants detected in the sewage of the textile industry in Europe are presented in Figure 8a. Therefore, it was decided to study their effect on the sorption capacity of DVB-\(co\)-GMA-TETA microspheres. In the present study, the impact of auxiliaries such as Na\({}_{2}\)SO\({}_{4}\) (5-25 g/L), CH\({}_{3}\)COOH (0.25-1.5 g/L) and anionic surfactant sodium dodecyl sulfate (SDS; 0.1-0.5 g/L) were investigated on the dye (\(C_{0}=100\) mg/L) uptakes (Figure 8b-d). \begin{table}
\begin{tabular}{c c c c} \hline \hline \multirow{2}{*}{**Parameter**} & \multicolumn{3}{c}{**Dye**} \\ \cline{2-4}  & **AV1** & **AR18** & **AG16** \\ \hline \(q_{exp}\) (mg/g) & 85.0 & 88.7 & 59.9 \\ \hline \multicolumn{4}{c}{**PFO**} \\ \hline \(q_{e}\) (mg/g) & 80.9 & 78.6 & 48.5 \\ \(k_{1}\) (1/min) & 0.0299 & 0.0464 & 0.0450 \\ MPSD & 0.361 & 0.499 & 0.689 \\ \(R^{2}\) & 0.991 & 0.951 & 0.916 \\ \(R^{2}_{adj}\) & 0.987 & 0.936 & 0.892 \\ \hline \multicolumn{4}{c}{**PSO**} \\ \hline \(q_{e}\) (mg/g) & 100.6 & 91.3 & 56.5 \\ \(k_{2}\) (g/mg min) & 0.0003 & 0.0005 & 0.0008 \\ MPSD & 0.339 & 0.326 & 0.462 \\ \(R^{2}\) & 0.989 & 0.977 & 0.959 \\ \(R^{2}_{adj}\) & 0.986 & 0.971 & 0.947 \\ \hline \multicolumn{4}{c}{**IPD**} \\ \hline \(q_{e}\) (mg/g) & 85.6 & 66.3 & 90.01 \\ \(k_{i}\) (mg/g min\({}^{0.5}\)) & 10.39 & 8.88 & 4.95 \\ \(R^{2}\) & 0.939 & 0.991 & 0.989 \\ \(R^{2}_{adj}\) & 0.922 & 0.990 & 0.986 \\ \hline \hline \end{tabular}
\end{table} 
Table 5: Kinetic parameters of sorption determined in the 100 mg/L AV1/AG16/AR18–DVB-\(co\)-GMA-TETA systems. Increasing the amount of Na\({}_{2}\)SO\({}_{4}\) and CH\({}_{3}\)COOH in the systems caused an increase of the \(q_{t}\) values. The amount of AG16 sorbed by the DVB-_co_-GMA-TETA increased from 26.7 mg/g to 61.1 mg/g with increasing concentration of Na\({}_{2}\)SO\({}_{4}\). An almost two-fold increase in the amount of AV1 adsorbed by the resin (\(q_{t}\) = 93.5 mg/g) in the 5-25 g/L Na\({}_{2}\)SO\({}_{4}\)-100 mg/L AV1 system was noted compared to solutions without electrolyte (\(q_{t}\) = 48.3 mg/g). This can be explained by the salting out effect. The solubility of the dyes in the water phase changes, which favors its adsorption in the resin phase. It was found that in the presence of CH\({}_{3}\)COOH, the amount of dyes retained by the microspheres increased significantly (from 26.7 to 86.4 mg/g for AG16, from 48.3 to 97.5 mg/g for AV1 and from 46.1 to 86.9 mg/g for AR18). In acidic medium, protonation of the amine functionalities occurs and the interaction between dye anions and positively charged groups of the resin is enhanced. Such observations were described in the case of the azo dye adsorption on polystyrene and polyacrylic anion exchangers [32; 33], C.I. Acid Orange 10 on an anion exchange resin (crosslinked acrylic copolymer based on divinylbenzene, ethyl acrylate and acrylonitrile functionalized with triethylenetetramine) [34]. Analyzing the adsorption efficiency of the azo dyes, i.e., AV1 and AR18, their enhanced retention on the resin in the presence of the anionic surfactant SDS was observed, while the adsorption of the triarylmethane dye AG16 decreased significantly with increasing SDS content in the system from 0.1 to 0.5 g/L. In the case of AV1 and AR18 adsorption, hydrophobic interactions between aromatic rings in dye anions and matrix of the resin play a dominant role in the retention mechanism.