壳聚糖对白芍水提液的絮凝效果及絮体的分形特性

分形维数是壳聚糖絮凝中药水提液絮体的重要参数,采用图像法测定絮体的分形维数,并应用Zeta电位仪测定了絮凝体系的ζ电位,对絮凝机理和絮凝效果进行了研究.选用壳聚糖作为絮凝剂,对白芍水提液进行净化除杂,通过改变絮凝剂投加量、絮凝温度、絮凝pH值等操作条件,探究这些因素对絮凝效果的影响,分析不同条件下絮体分形维数的变化规律:随着絮凝剂投加量的增加,絮体分形维数呈下降趋势;絮体分形维数随温度或pH值的升高出现先增大后降低的情况.通过正交实验确定白芍水提液的最佳工艺条件为絮凝剂投加量0.310g·L~(-1),絮凝温度30℃,絮凝pH值3,絮凝率达到94.32%,此时的分形维数为1.430.

Flocculation effect and flocs' fractal characteristics of peony's water-extraction with chitosan

The fractal dimension is an important parameter of flocculation of traditional Chinese Medicine's water-extraction with chitosan. In this paper, Flocs' fractal dimension is determined by image method, and Zeta potential instrument is applied to determine the ζ potential of flocculation system, so as to explore the mechanism and effect of the flocculation. Chitosan is selected as a flocculant to purify the impurity of water-extract of peony, the flocculation's operating conditions, such as the dosage of flocculant, flocculation temperature, pH value and so on, are adjusted to explore the impact of these factors on the flocculation and the variation of flocs' fractal dimension. When the dosage is increased, the fractal dimension of flocs shows a downward trend. When the temperature or pH value is increased, the fractal dimension of flocs shows a situation that it increases firstly, then decreases. The optimum conditions of peony's water-extract is acknowledged by orthogonal experiment:flocculant dosage is 0.310 g·L^-1, flocculation temperature is 30℃, pH value is 3. In this case, the flocculation flocculation rate is 94.32% when the fractal dimension is 1.430.