Fast and highly efficient adsorption of cationic dyes by phytic acid crosslinked β-cyclodextrin

In this study, a novel adsorbent (PA-β-CD) capable of fast and efficient adsorption of cationic dyes was successfully prepared by the poly-condensation reaction of phytic acid (PA) and β-cyclodextrin (β-CD). Results showed that PA-β-CD exhibited high adsorption capacities of 1095, 2005.58, 1736.32, and 1930.23 mg/g for methylene blue (MB), basic green 4 (MG), astrazon pink FG (FG), and crystal violet (MV), respectively. In addition, the adsorption of cationic dyes on PA-β-CD was very fast, and most of cationic dyes were adsorbed in the first 2 min. Moreover, PA-β-CD could selectively adsorb the cationic dye from a cationic/anionic dye mixture. Adsorption data revealed that the adsorption kinetics fitted the pseudo-second-order model well, and the isotherms were well described by a Langmuir isotherm model. The regeneration efficiency of the adsorbent remained above 90% after the fifth cycle. The present work confirmed that PA-β-CD shows great potential in the treatment of dye wastewater.