Abstract:

The β-cyclodextrin/tannin composite microspheres （β-CD/TA） were prepared by reverse suspension crosslinking polymerization, using β-cyclodextrin and tannin as monomers, and epichlorohydrin as a crosslinker. The microspheres were characterized by infrared spectroscopy and X-ray diffraction, which proved that tannin was successfully immobilized on β-cyclodextrin. Taking methylene blue （a cationic dye） as the model organic adsorbent, the effects of the pH and mass concentration of the initial solution of the dye on the adsorption performance of the microspheres were investigated. The adsorption experiment showed that the synergistic action between β-cyclodextrin cavity and tannic hydroxyl group was beneficial to improve the electrostatic adsorption between microspheres and methylene blue under neutral pH conditions, and the adsorption rate was 80.31%. When the initial concentration of methylene blue was increased to 1 000 mg/L, the gaps in the network were filled, the adsorption sites tended to be saturated, and the maximum adsorption capacity reached 630.41 mg/g. The β-cyclodextrin/tannin composite microspheres have good reuse performance, which greatly improves the application value of the two monomers in the field of industrial wastewater adsorption.

Key words: β-cyclodextrin, tannin, microsphere, methylene blue, adsorption