Abstract:

The rosin-based magnetic microspheres were synthesized by using maleic rosin acid-ethanediol-acrylic ester and methacrylic acid as functional monomer and ferriferrous oxide as magnetic source via suspension polymerization and amidation reaction. The structural and morphological properties of rosin-based magnetic microspheres were characterized by TG, FT-IR, BET, SEM and magnetic balance, and its static adsorption behavior for Cr(Ⅵ) was analyzed. The results showed that the rosin-based magnetic microspheres had paramagnetism(magnetic susceptibility was 9.123×10^-4 cm³/g) and functional group(amino). The specific surface area, pore volume and average pore size were 29.73 m²/g, 0.396 cm³/g and 18.023 nm. And there were many holes in the surface and internal. The optimum static adsorption conditions were obtained as follows: pH value 2, absorbent dosage 0.8 g, adsorbent particle size 72-108 μm. Under these conditions, the equilibrium adsorption(Q_e) was 67.5 mg/g after 4 h at 25 ℃ in 50 mL 0.5 g/L Cr(Ⅵ) solution. The pseudo-first-order kinetic equation that could well describe adsorption process was established, and the adsorption processes were affected by film diffusion and intra-particle diffusion. After using for 5 times, the removal rate of microspheres still reached 85% of the first adsorption, which indicated that the microspheres had good reusability.

Key words: rosin-based magnetic microspheres, adsorption, Cr(Ⅵ), kinetics