Effect of feed conditions and added solutes on the performance of membrane nanofiltration of succinic acid solutions

Predictive study of succinic acid transport via nanofiltration membranes using a Maxwell–Stefan approach

“…Even if exact match of experimental results is not achieved, the model indeed is successful in describing the acid rejection behavior in the presence of glucose. Experimentally, acid rejection decreases in the presence of glucose due to concentration polarization, as mentioned by Diaz et al 11 . The model also shows a decrease in acid rejection in the presence of glucose despite of the fact that the model does not consider concentration polarization.…”

“…For all experiments, in both Figs 3 and 4, it is observed that both modeled and experimental rejection increases with permeate flux. This is because total permeate fluxes increase with pressure but, since solvent flux is most affected by this increase than the solute flux, the solutions become more diluted in the permeate side, increasing the rejection values 11,33 …”

“…Also, the solvation phenomenon was not considered, leading to modeled glucose rejection remaining unchanged when succinic acid concentration increases. However, the model gives an idea of what would happen with glucose rejection if the phenomenon of solvation were not to be considered in the experimental results, where glucose rejection would keep constant in the presence of succinic acid 11 …”

“…Nowadays, in the case of fermentation, nanofiltration is being explored mostly for the concentration of the fermentative broth after the removal of microorganisms, for the separation of the desired product from salts and for the recovery of the unconverted carbon source aiming at reuse. Nanofiltration of organic acid solutions has been therefore widely studied 6–11 . On the other hand, one should point out that transport phenomena in nanofiltration as a process still require a detailed description and the elucidation of existing models that describe the performance of membranes in these systems is still required 12,13 .…”

“…Other parameters were solvent viscosity, membrane hydraulic permeabilities and solute diffusivities in water 11,31 : η = 0.0011 Pa s; L p,NFD − PI = 1.10 × 10 −11 m 3 m −2 s −1 Pa −1 ; L p,NFX = 8.44 × 10 −12 m 3 m −2 s −1 Pa −1 ; × 10 −6 cm 2 s −1 ; × 10 −6 cm 2 s −1 (5% less than undissociated acid 32 ).…”