Ultrafiltration and nanofiltration for the purification of sugar beet molasses utilised in the 5-hydroxymethylfurfural formation process

Activity: Talk or presentationPresentation


Sugar beet molasses is an underutilized by-product obtained from sugar mills, which is today mainly used for animal feed. The sugar compounds in the beet molasses, such as sucrose, are suitable raw materials for biorefinery processes. Among the different platform chemicals which can be produced in biorefineries, 5-Hydroxymethylfurfural (5-HMF) is a promising candidate for creating several different chemical building blocks and polymers. However, the 5-HMF formation process is affected by the purity and concentration of the raw materials used. In this study, two membrane processes, ultrafiltration (UF) and nanofiltration (NF), were studied for the purification of the sucrose fraction in the molasses. Two ceramic tubular modules were evaluated for the concentration of diluted molasses in cross-flow filtration mode. An UF membrane (Atech, Germany) with 10kDa MWCO and a NF membrane (IKTS Fraunhofer, Germany) with 200Da MWCO were used. During the concentration studies of the molasses, high normalised fluxes of 11-34 L/(m2h bar) (UF) and 14-27 L/(m2h bar) (NF) were achieved at 60˚C under volume reductions of 65-85%. During the trials significant membrane fouling was observed which resulted in pure water flux declines of 35 – 65%. However, it was possible to closely recover the original pure water flux (>80%) with optimised sequences of acid, alkaline and enzymatic cleaning agents. During the analysis of the retention of the different membranes using HPLC, significant differences for the sugar components were observed. Therefore, Dynamic Light Scattering was used to determine aggregate formations of the feed solution which revealed large variations of particle sizes distribution depending on molasses concentration. The purified molasses from both UF and NF was concentrated by evaporation and tested for 5-HMF production. The results from the 5-HMF production based on the purified and raw molasses were assessed and compared in a techno-economical evaluation.
Period2020 Dec 72020 Dec 11
Event title12th International Congress on Membranes and Membrane Processes
Event typeConference
LocationLondon, United KingdomShow on map
Degree of RecognitionInternational

UKÄ subject classification

  • Chemical Engineering

Free keywords

  • Membrane processes
  • Sugar beet molasses
  • HMF production
  • Biorefineries