表面修饰聚乙烯亚胺的壳聚糖微球对十二烷基苯磺酸钠的吸附特性

采用乳化交联法制备交联壳聚糖微球(CCS)，在其表面接枝聚乙烯亚胺(PEI)，得到系列具有不同离子交换容量(IEC)的PEI修饰交联壳聚糖微球(PEI-CCS)，对其进行表征，考察了其对十二烷基苯磺酸钠(SDBS)的静态吸附特性. 结果表明，PEI-CCS平均粒径为85 mm，IEC最高达1275 mmol/g，远高于CCS的418 mmol/g. 酸性条件下，PEI-CCS的胺基质子化，带正电荷，能与溶液中的阴离子吸附结合，对SDBS有良好的吸附能力. 吸附过程自发放热，可用准二级动力学模型和Langmuir吸附等温模型描述. PEI-CCS对SDBS的最大吸附量随IEC增加而增大，IEC=1275 mmol/g的PEI-CCS的最大吸附量为1487.61 mg/g，是CCS最大吸附量(510.20 mg/g)的2.92倍，吸附-脱附7次循环后，吸附量下降17.8%. PEI-CCS具有良好的重复使用性.

Adsorption Properties of Sodium Dodecylbenzenesulfonate onto Surface-modified Chitosan Microspheres with Poly(ethylenimine)

Crosslinked chitosan microspheres (CCS) were prepared by emulsion crosslinking, their surface was then grafted with poly(ethylenimine) (PEI) to synthesize a series of PEI modified crosslinked chitosan microspheres (PEI-CCS) with different ion exchange capacities (IEC). The prepared PEI-CCS were characterized, and their static adsorption properties of PEI-CCS to sodium dodecylbenzenesulfonate (SDBS) studied. The results showed that the mean diameter of PEI-CCS was 85 mm. The highest IEC of PEI-CCS reached 1275 mmol/g, being much higher than that of CCS (418 mmol/g). At acidic pH values, the amine groups of PEI-CCS carried positive charges by protonation, and could adsorb anions in aqueous solution. Thus, PEI-CCS exhibited excellent adsorption performance toward SDBS. The adsorption process was spontaneous and exothermic, and well described by the pseudo-second-order kinetic and Langmuir isotherm models. The maximum adsorption capacity of PEI-CCS increased with increasing of IEC. The maximum adsorption capacity of PEI-CCS-1275 with the highest IEC reached 1487.61 mg/g and was 2.92-fold of CCS (510.20 mg/g). The adsorption capacity of PEI-CCS-1275 was reduced by 17.8% after seven cycles of adsorption-desorption, indicating that PEI-CCS had good reusability for the adsorption of SDBS.