# Application of Ultrafiltration for Recovery of Bioactive Phenolic Compounds from Rose Wastewater
## 3 Results and Discussion
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**No.** & **Solution type:** & **Membrane** & **1 kDa** & **10 kDa** & **25 kDa** \\ \hline \multicolumn{5}{c}{**Total phenolic compounds, mg/dm3 gallic acid equivalent**} \\
1 & Initial rose wastewater & 1646.66 \(\pm\) 10.78 a & 1646.66 \(\pm\) 10.78 a & 1646.66 \(\pm\) 10.78 a \\
2 & Retentate at VRR 2 & 1638.55 \(\pm\) 8.24 a,A & 1415.89 \(\pm\) 6.87 b,B & 1546.66 \(\pm\) 42.51 b,C \\
3 & Retentate at VRR 4 & 2164.40 \(\pm\) 48.79 b,C,A & 1736.90 \(\pm\) 15.38 c,B & 1547.47 \(\pm\) 50.46 b,C \\
4 & Retentate at VRR 6 & 2164.49 \(\pm\) 50.74 b,A & 1727.90 \(\pm\) 19.41 c,B & 1581.32 \(\pm\) 12.71 b,C \\
5 & Retentate at VRR 8 & 2391.57 \(\pm\) 19.87 c,A & 1844.56 \(\pm\) 10.01 d,B & 1885.77 \(\pm\) 2.95 c,C \\
6 & Permeate & 1384.64 \(\pm\) 13.34 d,A & 1154.66 \(\pm\) 46.43 e,B & 1295.57 \(\pm\) 7.27 d,C \\ \hline \multicolumn{5}{c}{**Phenolic acids, mg/dm3 caffe acid equivalent**} \\
1 & Initial rose wastewater & 387.72 \(\pm\) 7.61 a & 387.72 \(\pm\) 7.61 a & 529.03 \(\pm\) 8.89 a \\
2 & Retentate at VRR 2 & 381.06 \(\pm\) 3.69 a,A & 323.54 \(\pm\) 7.51 b,B & 503.52 \(\pm\) 14.20 b,B \\
3 & Retentate at VRR 4 & 499.32 \(\pm\) 14.04 b,A & 404.61 \(\pm\) 5.79 c,B & 503.73 \(\pm\) 9.87 a,C \\
4 & Retentate at VRR 6 & 500.07 \(\pm\) 4.37 b,A & 404.86 \(\pm\) 4.64 c,B & 521.58 \(\pm\) 1.61 b,C \\
5 & Retentate at VRR 8 & 556.94 \(\pm\) 12.88 c,A & 425.96 \(\pm\) 6.93 d,B & 608.63 \(\pm\) 1.38 c,B \\
6 & Permeate & 317.65 \(\pm\) 7.18 d,A & 268.46 \(\pm\) 16.68 e,B & 423.38 \(\pm\) 3.22 d,C \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Total phenolic compounds, phenolic acids, and flavonoid phenolic compounds in the initial rose wastewater, retentates, and permeates. Figure 2: Energy demand compared to the volume reduction ratio during the ultrafiltration of rose wastewater. The effect of the VRR on the concentration factor of total phenolic compounds, phenolic acids, and flavonoid phenolic compounds during the ultrafiltration of rose wastewater are presented in Figure 4. The concentration factor increased with the rise in the VRR in all the compounds tested and membranes studied (\(p<0.05\)). Regarding the different membranes, there was an inverse proportional relationship between the corresponding molecular weight cut-off and the concentration factor. The highest values in concentration factor of total phenolic compounds (1.45), phenolic acids (1.44), and flavonoid phenolic compounds (1.45) were obtained with the 1 kDa membrane. According to [PERSON] et al. [45], the concentration of polyphenols in the retentate increased exponentially during apple juice filtration. The separation and concentration of the compounds also depend on the membrane's material. [PERSON] et al. [34] compared membranes with a molecular weight cut-off of 50 kDa of polyethersulfone (PES), polyvinylidene fluoride (PVDF), and polyacrylamideonitrile (PAN) during the ultrafiltration of apple juice and obtained the highest value of total phenolic content with the PVDF membrane. [PERSON] et al. [48] found that the phenolic concentration of wine lees extract after ultrafiltration depended not only on the membrane's