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松香基磁性微球的结构表征及其对Cr(Ⅵ)的吸附性能

Structural Characterization of Rosin-based Magnetic Microspheres and Their Adsorption Properties of Cr(Ⅵ)

  • 摘要: 以马来松香乙二醇丙烯酸酯和甲基丙烯酸为单体,Fe3O4为磁源,通过悬浮聚合和酰胺化反应制备出松香基磁性微球。利用热重分析仪、红外光谱、比表面积与孔隙度分析仪、扫描电镜及磁天平对磁性微球进行表征,并通过静态吸附法研究了其对Cr(Ⅵ)的吸附性能。结果显示:松香基磁性微球既具有顺磁性(磁化率为9.123×10-4 cm3/g),又具有功能基团(氨基),比表面积、孔体积和平均孔径分别为29.73 m2/g、0.396 cm3/g和18.023 nm,表面和内部均有大量孔洞。当磁性微球粒径为72~108 μm时, 在50 mL质量浓度为0.5 g/L Cr(Ⅵ)溶液中,调节pH值为2, 吸附剂用量为0.8 g,25 ℃下振荡吸附,吸附平衡时间为4 h时,平衡吸附量为67.5 mg/g。动力学方程拟合结果显示吸附速率符合准一级动力学方程,吸附过程受液膜扩散和颗粒内部扩散共同影响。磁性微球循环使用5次,去除率仍达第一次吸附的85%以上,具有很好的循环使用性能。

     

    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(Qe) 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.

     

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