On the effect of a non-ionic surfactant on the surface of sucrose crystals and on the crystal growth process by inverse gas chromatography

The effect of Hodag CB6, a widely used non-ionic surfactant in sugar crystallization process, on the surface properties of sucrose was studied in detail by inverse gas chromatography (IGC) experiments. IGC experiments were performed with pure sucrose crystals, surfactant coated sucrose crystals, and crystals grown in the presence of surfactant at 313.05 and 323.05 K. The surfactant promotes the specific interactions with the polar probes. The sorption of basic, acidic and amphoteric probes onto pure and surfactant coated sucrose was found to be endothermic and in the case of neutral probes was found to be exothermic. The surfactant increases both the acidity and basicity of the sucrose surface with the latter effect being significant. The role of interfacial tension on the growth kinetics of sucrose crystals was studied using IGC for different surfactant concentrations. IGC results with the surfactant coated sucrose were used to interpret the thermodynamic effect of surfactants during the crystal growth process. The dispersive component of the surface energy, γsD, of surfactant coated sucrose crystals was found to be lower than that of pure sucrose crystals and was found to be in the range of 33.49–35.27 mJ/m2.