混合生育酚在强碱性树脂上的吸附行为研究

Adsorption behaviors of tocopherol by strong-base anion exchange resin

以经分子蒸馏后的混合生育酚粗品为原料,采用离子交换法将混合生育酚以及生育酚同系物进行分离。研究发现强碱性树脂对生育酚的静态吸附需要7h左右能达到平衡。树脂吸附生育酚的过程是个放热过程,随着温度的升高,生育酚的吸附量明显下降,35℃干树脂对生育酚的吸附最大值可达到506.1mg/g。常规的静态试验所得到的表观吸附等温线是条折线,这一特异性的现象是原料中游离脂肪酸对生育酚竞争吸附的结果,树脂对脂肪酸的亲和力要大于对生育酚的亲和力。在动态试验中,流出曲线表明生育酚各同系物流出顺序与其酸性大小有关,酸性最弱的α-生育酚最先穿透,其次是β+γ-生育酚,而酸性最强的δ-生育酚则最后穿透。随着进料质量浓度和流速的增大,系统的非理想性增强,卷起现象减弱。在描述解吸行为的解吸曲线中,各组分卷起的程度大小是:δ-生育酚>β+γ-生育酚>α-生育酚。

Tocopherol and their homolog were separated from crude produα by ion exchange technology. The static adsorption for tocopherol by a strong-base anion exchange resin indicated that equilibrium could be reached after 7 h. The adsorption process was an exothermal reaαion and the adsorption capacity for tocopherol decreased with the increase of temperature. At 35℃, the maximum adsorption capacity was 506.1 mg/g （ based on dry resin）. The special charaαer of tocopherol adsorption isotherm suggested that the free fatty acid of the crude produα could compete with tocopherol for the adsorption sites on the resin. The dynamic adsorption experiments revealed that the penetration sequence was related to the acidity of the components, and followed the order of δ - tocopherol 〉 β＋γ-tocopherol 〉 α - tocopherol. Moreover,with the increase of the flow rate and tocopherol concentration in feed stock, the non-ideal charaαer of the mixture increased and the extent of overshoot decreased. The desorption curve showed that the extent of overshoot followed the order δ - tocopherol 〉β＋γ- tocopherol 〉 α - tocopherol.