Artemisinin is mainly derived from Artemisia annua L. Since the leaves composition is complex, artemisinin purification faces great challenges. In this work, functional chitosan membranes were fabricated by a one-step hydrolysis method through grafting long-chain alkyl group on the surface of chitosan to increase its hydrophobicity. The as-prepared membranes were used to adsorb wax oil (i.e., the impurity components) in Artemisia annua L. and to avoid co-precipitation of wax oil along with artemisinin using the crystallization technique for purification. Octyl-trimethoxysilane modified chitosan membrane (FCM-C8) showed excellent capability to intensify this purification process. The product purity could reach more than 98 % using one crystallization step under the optimal conditions, and in this case, adsorption capacity of FCM-C8 for wax oil was 478.9 mg/g. In addition, the adsorption kinetics and mechanism of wax oil on FCM-C8 were studied. The membrane can simultaneously adsorb multiple components in wax oil through interactions like electrostatic forces, hydrogen bondings.
Keywords: Artemisinin; Functional chitosan membrane; Kinetics; Mechanism; Purification.
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