Adsorption of cationic starch on aluminum magnesium hydrotalcite-like compound

Hydrotalcite-like compounds (HTlc) is a new large family of layered inorganic materials with positive structural charges and cationic starch (CS) is a large-scale commercial product. CS–HTlc aqueous dispersion is expected to be used in many fields such as drug delivery and the recover of oil, the adsorption of CS on HTlc may play an important role on its properties and applications. However, to the best of our knowledge, no other previous work was reported on the adsorption of CS on HTlc. In this paper, the adsorption of CS on Mg–Al HTlc was investigated. The following results were obtained. CS may be adsorbed on the external surface of positively structurally charged Mg–Al HTlc, which is an entropic driving process. The adsorption isotherms are low-affinity Langmuir type, and the adsorption kinetic shows an overshoot, which may be ascribed to the CS clustering. The addition of NaCl and AlCl3 may evidently increase the adsorption. The increases of pH and temperature may result in the increase of the adsorption.