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 andTheir Adsorption Properties of Cr(Ⅵ)

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. 123×10-4cm3/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72～108μm时,在50 m L质量浓度为0. 5 g/L Cr(Ⅵ)溶液中,调节p H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。

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 cm^3/g)and functional group(amino).The specific surface area,pore volume and average pore size were 29.73 m^2/g,0.396 cm^3/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 108μm.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.