## 3 Results and Discussion
### Separation of RB8 from Real Wastewater  
Finally, we verified the separation of the RB8 dye from real wastewater (aqueous filtrate obtained from industrial RB8 separation). The initial concentration of RB8 in this wastewater is 7 g L\({}^{-1}\); for further specifications, see Section 2.1. Chemicals. Based on the optimization experiments within the separation of RB8 dye from model wastewater, we tested the most promising methods--the co-action of BC or BT with BAC for real wastewater purification. As Figure 9 depicts, the BC alone in an appropriate dosage of 280 g per one liter of real wastewater proved approx. 20% lower decolorization and 15% lower COD removal than experiments with the separation of the tested dye from model wastewater. The lower efficiencies of RB8 removal may be caused by the complex matrix of real wastewater which contains not only RB8 but even different by-products or unreacted reactants. The increasing of BC dosage above 280 g L\({}^{-1}\) would not be economical. On the other hand, the same dose of PAC (280 g L\({}^{-1}\)) is able to reach 92% decolorization and 74% removal of COD; see Figure 9.  
Afterward, the method of the co-action of BC with BAC was investigated for the purpose of enhancing the separation ability of RB8 dye from real wastewater. For model wastewaters containing 1 g L\({}^{-1}\) of RB8 dye, the optimal dosage was established at 1.5 g L\({}^{-1}\) of BAC and 2 g L\({}^{-1}\) of BC. Therefore, we tested seven times higher doses of these reagents for real wastewater containing 7 g L\({}^{-1}\) of RB8 dye (seven times higher RB8 content than in model wastewater). However, these previously optimized doses of BC and BAC achieved only 40% decolorization and 22% removal of COD from real wastewater; see Figure 9.  
Therefore, increasing BAC and BC doses was examined to enhance the removal of the RB8 dye. BAC (28 g L\({}^{-1}\)) in co-action with 56 g L\({}^{-1}\) of BC is able to achieve almost 99% decolorization and 78% COD removal. In other words, for a comparable removal effectiveness of the RB8 dye from real wastewater, the addition of a 2.7 times higher dose of BAC and 4 times higher dose of BC compared with model wastewater is required; see Figure 9.  
Figure 9: Optimization of co-action of BAC (50%) and BC within the separation of RB8 from real wastewater (containing 7 g L\({}^{-1}\) of RB8 dye among others) after 5 h of action. (Removal efficiencies of sole PAC are added for comparison of removal robustness of BAC/BC system). Analogously, we scrutinized the optimized method of direct combination of BAC with the second alternative sorbent BT for the separation of RB8 from real wastewater; see Figure 10. In contrast to BC (see Figure 9), the previously optimized dosages of 14 g L\({}^{-1}\) of BAC and 28 g L\({}^{-1}\) of BT applied for the treatment of real wastewater containing 7 g L\({}^{-1}\) of RB8 dye achieved satisfactory removal efficiency (90.6% decolorization and 84.5% COD removal). The optimal dose of BT + BAC was verified as 20 g L\({}^{-1}\) of BAC and 28 g L\({}^{-1}\) of BT which offer 96.1% decolorization and 90.7% removal of COD; see Figure 10. Therefore, it is required to use only a 1.4 times higher dose of BAC and a 4 times higher dose of BT than in the case of model wastewater. Figure 11 illustrates the rates of RB8 sorption on PAC alone and alternativeorbents in co-action with BAC from real wastewater using the above-optimized doses oforbents. The equilibrium of RB8 sorption on virgin PAC was established after 240 min. On the other hand, upon the action of BC or BT with BAC, the equilibrium state was gained after 90 min or 60 min, respectively. From the obtained results, it is evident that the most promising method of direct combination of BAC with BT for RB8 dye from real wastewater is rapid and as effective as the more expensive PAC treatment [21].