Description of membrane fouling characteristics during ultrafiltration of organic foulants contained in sweetwater solutions

• We carry out the ultrafiltration of organic solutes simulating sweetwater solutions which are long chain fatty acid (FA) and triglyceride (TG).
• We examine the changes on the membrane surface as well as within the interior after ultrafiltration with SEM, AFM, FTIR and contact angle.
• Reducing the pH of the feed solution will make the oil droplets and FA agglomerate and coalesces and induced their deposition on the membrane surface and pore wall.
• Increasing the pH will promote the saponification between the fat and hydroxide, thus reduce the contribution of solutes deposition.
• Essentially, the combination of pore blockage and cake formation dominate the fouling mechanism during ultrafiltration of FA and TG.

The characterization and the filtration behavior of commercial ultrafiltration (UF) membranes used in the removal of triglycerides (TG) and combined mixtures (TG
• fatty acid) from glycerol
• water solution were examined. Flat sheet ultrafiltration (UF) polyethersulfone and polyvinylidenfluoride membranes were used for comparison. Glycerol
• water solutions were synthesized as feed and the influences of membrane surface chemistry and pH solutions were studied. Fouling behavior of TG and TG
• FA were analyzed by scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform spectroscopy (FTIR), contact angle and surface energy measurement. Results from this work reveal that hydrophobic surfaces are more prone to TG and FA deposition than less hydrophobic surfaces in glycerol
• water mixture. SEM morphologies and cross structure as well as FTIR spectrums revealed that the membranes were severely fouled with TG (oil droplets) instead of TG
• FA. Further, contact angle measurements obtained in this work showed that the angles tended to decrease with oil wetted material and in acidic conditions.