Fouling of nanofiltration membranes used for separation of fermented glycerol solutions

Abstract

In this study, the glycerol solutions were fermented using Lactobacillus casei bacteria. The broths were pre-treated by microfiltration, followed by a further separation with nanofiltration. The latter process was carried out in two stages, using the NF270 and NF90 membranes, respectively. The concentrates thus obtained were enriched with citric acid (first stage) and then with lactic acid and glycerol (second stage). By means of SEM and AFM microscopy, as well as ATR-FTIR analysis, the intensity of membrane-fouling was studied. The colloidal fouling and bio-fouling caused a more than two-fold decrease in the permeate flux during microfiltration of the broth. This pre-treatment stage was effective, and a permeate turbidity of less than 0.2 NTU was obtained. However, the nanofiltration membranes exhibited a 30 % flux decline over the course of the process, mainly due to the organic fouling.

The study of glycerol-based fermentation and broth downstream by nanofiltration

“…An electrodialysis was found to be an effi cient way for salts removal and the recovery from fermentation broth 20 . The nanofi ltration (NF) is other effective process that can be used for broth desalination…”

Monitoring the Salt Stability of Layer‐by‐Layer Self‐Assembled Films From Polyelectrolyte Blends by Quartz Crystal Microbalance‐Dissipation and Their Ion Separation Performances

“…6a. The average contact angle values of (PAH/PAA50-PSS50) 60 and (PVA/PAA50-PSS50) 60 were determined as 52 AE 1 and 45 AE 1 , respectively ( Fig. 6b and d).…”

Studies of polypropylene membrane fouling during microfiltration of broth with Citrobacter freundii bacteria

“…However, the retention of bacteria was not complete, and the MF permeate contained over 10 3 -10 4 cells, whereas bacteria concentration in the feed was at a level of 10 11 . These bacteria were retained when the PTFE membrane (0.2 μm, Millipore) was applied 28 . It was found that a type of membrane material and the cell-wall fl exibility triggers the transfer of the bacteria through the membranes, when the pores are smaller in size than the cell 2, 29 .…”

“…It was found that a type of membrane material and the cell-wall fl exibility triggers the transfer of the bacteria through the membranes, when the pores are smaller in size than the cell 2, 29 . However, a signifi cant fouling was observed due to a high hydrophobocity of PTFE 28 . A lower hydrophobocity has a polypropylene, thus the PP membranes were used in this work for MF of broth with C. freundii bacteria, which was applied for 1,3-PD syntheses from glycerol.…”

“…The used solutions of P3-ultrasil 11 beside other components contained NaOH. For used in this work broth, the UF membrane was effective cleaned when a 1 wt% NaOH was used 5, 28 . Therefore, this rinsing agent was used also in this studies, and the initial permeate fl ux, about 110-113 L/m 2 h, was restored (Fig.…”