Adsorption mechanism of copper ions in aqueous solution by chitosan–carboxymethyl starch composites

ABSTRACT Based on the structural characteristics of chitosan (CTS) and carboxymethyl starch (CMS)， CTS–CMS composites were prepared by crosslinking. The composites had a plurality of reactive functional groups such as NH 2 , NH 3 + , COOH, and OH and are applied to the adsorption of Cu 2+ in aqueous solution. The adsorption capacity and stability in acidic solution of the composites were preferable to that of raw material. The effects of temperature, contact time, initial concentration, and pH on the adsorption of Cu 2+ were investigated. Infrared spectroscopy, scanning electron microscope–energy dispersive spectrometer, X‐ray diffraction, and X‐ray photoelectron spectroscopy were used to explore the adsorption mechanism. The experiment showed that chemisorption and physisorption coexisted in the adsorption process. It is promising to apply this adsorbent to remove the metal ions in wastewater. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137 , 48636.