Abstract:Environmentally friendly regeneration of resins is of the reason to use ion-exchange technique in the sugar industry. Here, the regeneration of syrup decalcification resin using conventional sodium chloride as the regeneration agent in the presence of alcohol-soluble pigments was evaluated. The desorption properties, desorption kinetics of decalcification resin, and effect of alcohol-soluble pigments on resin regeneration were evaluated. The results showed that the presence of alcohol-soluble pigments contributed to the recovery of decalcification resin, which is likely because the chelation of alcohol-soluble phenolic pigments and calcium salts promotes the regeneration of decalcification resin. The moving boundary model was used to describe the desorption kinetics of resin decalcification, and the results showed that the rate-determining step of the desorption process was particle diffusion. The reaction order was 1.14, apparent activation energy was 36.90 kJ/mol, and apparent frequency factor k0 was 1679 min-1. Further analysis of the kinetics showed that the desorption process could be described by a pseudo-second-order kinetic model (R2 > 0.99). Moreover, the desorption behavior of resin decalcification fit well with the Freundlich isotherm model, showing that the desorption process in this resin occurred through mono- or multi-molecular layer diffusion on heterogeneous surfaces. This study provides a novel approach for reducing the use of sodium chloride and for regenerating resins more efficiently and in an environmentally friendly manner in the sugar industry.
