Xia Hai-Feng, Lin Dong-Qiang, Yao Shan-Jing
Department of Chemical and Biochemical Engineering, Zhejiang University, Hangzhou 310027, China.
J Chromatogr A. 2008 Jun 27;1195(1-2):60-6. doi: 10.1016/j.chroma.2008.04.080. Epub 2008 May 13.
Macroporous cellulose-tungsten carbide composite beads was designed and prepared as an anion-exchanger for expanded bed adsorption (EBA). The wet density of composite beads was adjusted at the range of 1.2-2.4 g/ml with the control of tungsten carbide addition, and optimized for EBA at high fluid velocity. The results indicated that the wet density of composite beads could increase linearly with the increase of tungsten carbide addition, meanwhile other physical properties, such as size, porosity, specific surface area, mean pore diameter, etc., were hardly or slightly influenced. The composite beads were coupled with diethylaminoethyl (DEAE) as an anion-exchanger for EBA. The expansion characteristics in expanded bed were investigated and sensitively changed as the wet density of composite beads, corresponding to tungsten carbide addition in the preparation. The relation among the operation fluid velocity, the ratio of tungsten carbide to cellulose viscose in the preparation and the expansion factor was found, which could be used to predict the operation velocity of composite beads with varying tungsten carbide addition. The liquid mixing in expanded bed was also tested and showed good bed stability for EBA processes. With the adsorption equilibrium experiments, the saturated adsorption capacity of bovine serum albumin could reach 68.7 mg/g adsorbents (equal to 97.1 mg/ml adsorbents). The ratio of Q(10%) (the dynamic adsorption at 10% breakthrough) in expanded bed to packed bed could reach more than 90% for the fluid velocity of 500 cm/h, even 77.1% for the fluid velocity as high as 900 cm/h. The chromatographic results demonstrated that the composite beads prepared are suitable for EBA applications at high fluid velocity.
设计并制备了大孔纤维素 - 碳化钨复合珠，用作膨胀床吸附（EBA）的阴离子交换剂。通过控制碳化钨的添加量，将复合珠的湿密度调节在1.2 - 2.4 g/ml范围内，并针对高流体流速下的EBA进行了优化。结果表明，复合珠的湿密度随碳化钨添加量的增加呈线性增加，同时其他物理性质，如尺寸、孔隙率、比表面积、平均孔径等，几乎没有或仅有轻微影响。将复合珠与二乙氨基乙基（DEAE）偶联作为EBA的阴离子交换剂。研究了其在膨胀床中的膨胀特性，并发现随着复合珠湿密度（对应于制备过程中碳化钨的添加量）的变化而灵敏变化。找到了操作流体流速、制备过程中碳化钨与纤维素粘胶的比例与膨胀因子之间的关系，可用于预测不同碳化钨添加量的复合珠的操作流速。还测试了膨胀床中的液体混合情况，结果表明其对于EBA过程具有良好的床稳定性。通过吸附平衡实验，牛血清白蛋白的饱和吸附容量可达68.7 mg/g吸附剂（相当于97.1 mg/ml吸附剂）。对于500 cm/h的流体流速，膨胀床中Q(10%)（10%穿透时的动态吸附）与填充床中的比例可达90%以上，对于高达900 cm/h的流体流速，该比例甚至可达77.1%。色谱结果表明，所制备的复合珠适用于高流体流速下的EBA应用。
