## 3 Results
### Study of the Effect of Temperature on the Primary Separation of ABE-Fermentation Broth  
The temperature dependences of the permeate flux for PDecMS, PHeptMS, and MDK-3 membranes after contact with the ABE-fermentation broth during separation of the real ABE broth are shown in Figure 10. As the temperature of the separated mixture increased, the permeate flux tended to increase for all membranes, which was associated with an increase in the diffusion rate of penetrants through the selective layer. As a result of increasing temperature, the vapor pressure of organic substances and water increases, which leads to a higher driving force of permeate. In general, all membranes were characterized by a more than twofold increase in the flux of organic component when increasing the temperature from 30 to 60 \({}^{\circ}\)C. PDecMS was characterized by a slight increase in water flux from 0.04 to 0.15 kg/(m\({}^{2}\cdot\)h) with increasing temperature, compared to the MDK-3 membrane, for which the water flux increased from 0.29 (30 \({}^{\circ}\)C) to 1.12 (60 \({}^{\circ}\)C). The MDK-3 membrane was characterized by a sharper (almost linear) increase in fluxes of both organic components and water. The temperature dependences of the separation factors for the studied membranes after exposure to the fermentation broth do not look as unambiguous. The values of the separation factor at different temperatures are presented in Table 4.  
In the case of PHeptMS and MDK-3 membranes, a gradual increase in the n-butanol/water and acetone/water separation factors with increasing temperature was observed, while the acetone/water separation factor passed through a minimum (40 \({}^{\circ}\)C). In the case of PDecMS membranes, a decrease in the separation factors was observed with increasing temperature, except for the ethanol/water separation factor, which passed through the minimum at 45 \({}^{\circ}\)C. Such differences may be related to the mutual influence of the peptide and selective layer of the membrane on the transport. It is known that diffusion increases with increasing temperature due to increased molecular mobility, but sorption decreases. Accordingly, the increase in the separation factors of PHeptMS and MDK-3 membranes may be related to the desorption of protein components from the surface of the selective layer. The maximum values of the organic component/water separation factor in the temperature range studied were observed for the PHeptMS membrane--74 for butanol,61 for acetone, and 10 for ethanol at 60 \({}^{\circ}\)C. These values exceed the highest separation factors of the PDMS membrane obtained in [64], which were 33.36, 19.81, and 10.07 for acetone, butanol, and ethanol, respectively. When using a composite PDMS/ceramic membrane in the separation of the ABE-fermentation broth at 37 \({}^{\circ}\)C, the authors of [65] achieved a butanol/water separation factor of 27.3. The tendency of the permeate flow and the organic component/water separation factor to increase with increasing temperature was also observed in [66], where a POMS-based membrane was used in the separation of a model ABE solution. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Membrane** & \(\mathbf{\beta}\)**Butanol/Water** & \(\mathbf{\beta}\)**Acetone/Water** & \(\mathbf{\beta}\)**Ethanol/Water** & **Temperature, \({}^{\circ}\)C** \\ \hline \multirow{4}{*}{PHeptMS} & 41.5 & 45.3 & 5.5 & 30 \\  & 59.7 & 40.8 & 5.6 & 40 \\  & 74.4 & 60.9 & 10.5 & 60 \\ \hline \multirow{4}{*}{PDecMS} & 22.2 & 20.9 & 3.7 & 30 \\  & 19.3 & 17.7 & 2.6 & 45 \\  & 16.9 & 14.6 & 4.2 & 60 \\ \hline \multirow{4}{*}{MDK-3} & 12.8 & 26.6 & 2.7 & 30 \\  & 14.7 & 20.6 & 3.5 & 40 \\ \cline{1-1}  & 18.4 & 21.4 & 5.1 & 60 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Separation factor (\(\mathbf{\beta}\)) organic component/water for PHeptMS, PDecMS, and MDK-3 membranes at different temperatures.