Decoloration of sugarcane molasses by tight ultrafiltration: Filtration behavior and fouling control
- Authors
- Publication Date
- Jan 01, 2018
- Source
- Institutional Repository of Institute of Process Engineering, CAS (IPE-IR）
- Keywords
- License
- Unknown
- External links
Abstract
Economically viable recovery of sucrose from sugarcane molasses is of great interest to academia and industry, and membrane technology is promising to achieve this goal, especially the separation of pigments and sucrose. A suitable membrane should have higher permeate flux and color removal, as well as lower sugar loss and membrane fouling during the decoloration of the sugarcane molasses. Compared with polyether sulphone ultrafiltration (UF) membranes, a polyamide UF membrane with a molecular weight cut-off of 2 kDa was preferred for this purpose. To further control membrane fouling, alkali treatment on such membrane and different pretreatments on molasses were also examined. Alkaline treatment on the membrane could further increase its antifouling performance at the sacrifice of some color removal. The pretreatment with ceramic membrane filtration greatly increased the permeate flux of the polymeric membrane, but it only transferred the fouling from the polymeric membrane to the ceramic membrane, unfortunately, from reversible to irreversible fouling. Moreover, the UF permeate flux was improved at higher pH (neutral) and temperature (60 degrees C), and these conditions also could retard microbial growth and sucrose conversion. Higher dilution times on molasses enhanced the permeate flux of the OF and reduced the sugar loss, but the filtration time was prolonged. Moreover, the sucrose and reducing sugar retentions by nanofiltration (NF) membrane at 60 degrees C kept around 96% and 60% respectively, implying that separation of sucrose and reducing sugar after the decoloration of molasses could be realized. This work not only provides an alternative method to efficiently utilize sugarcane molasses, but also serves as a valuable guide for process design and practical operation in subsequent industrial application.
