Arginine-modified magnetic chitosan: Preparation, characterization and adsorption of gallic acid in sugar solution

The presence of phenolic substances in sugarcane juice seriously affects the color value of sugar products. Magnetic chitosan (MCS) was prepared using an ionic cross-linking technique, and then was modified with arginine to prepare arginine-modified magnetic chitosan (AMCS) for use as a new sucrose clarifying adsorbent. Gallic acid (GA) is a representative phenolic substance and was used to test the adsorption properties of the prepared AMCS. The adsorption kinetics indicated that the adsorption of GA on AMCS conformed to the pseudo-second-order model, the main adsorption mechanism was chemisorption. The Langmuir equation fit well and with good linearity, and indicated a maximum adsorption capacity of 48.38 mg g^-1. The adsorption process was consistent with monolayer adsorption and spontaneous endothermic process. The prepared AMCS exhibited excellent regenerability, and can effectively remove GA in sugarcane juice to improve product safety.