Removal of inorganic contaminants in sugar refining process using electrodeionization

• EDI is used to remove ionizable salts as well as colour body from sugar solutions.
• Experiments were conducted at both batch and continuous operation.
• Effect of process parameters are investigated.
• Colour removal mechanism is discussed.

This paper reports performance of an electrodeionization (EDI) system during removal of inorganic contaminants in sugar refining process. Diluate compartments of EDI stack were filled with mixed ion-exchange resins (strong acid cation-exchange and strong base type I anion resins). Experiments were then conducted at both batch and continuous operation mode. The results showed that EDI is able to remove inorganic contaminants as well as colour body from sugar solutions. At relatively high sugar concentration, significant decrease in ions removal is observed. The increase of current density and applied voltage had little impact on ions removal and lead to current efficiency and pH reduction. The colour removal may be associated to complex bond (organic–inorganic) breakage due to water dissociation inside the diluate compartment.