壳聚糖盐酸盐对老鹳草水提液絮凝效果及微观特性的影响

Influence of Chitosan Hydrochloride on Flocculation and Microscopic Properties of Herba Geranii Water-Extract

研究了壳聚糖盐酸盐对老鹳草水提液的絮凝澄清效果,利用微电泳仪、激光粒度分析仪及图像法对上清液的ζ电位、粒度分布及絮体的分形维数等微观特征参数进行测量和分析,考察其随絮凝剂用量的变化规律。实验结果表明：壳聚糖盐酸盐最佳投加剂量为0.196 g？L-1,此时杂质絮凝率为90.1%,有效成分总黄酮损失率为0.8%。在最佳絮凝剂投加量下,上清液的ζ电位趋近于零,胶体粒子处于等电态,容易发生絮凝和聚沉;上清液中颗粒的粒径分布在5~62μm,平均粒径值为10.88μm,与原液相比绝大部分大颗粒被沉降;絮凝体的二维分形维数达到最大值1.43,说明絮体结构致密。

Purification of herba geranii water-extract with Chitosan hydrochloride was studied. The microscopic parameters of the supernatant fluid including zeta potential, particle size distribution and fractal dimension of flocs were measured and analyzed by micro-electrophoresis, laser particle size analyzer and imaging approaches to investigate the effects of flocculant dosage on purification. Experimental results show that the optimum chitosan hydrochloride dosage is 0.196 g？L-1, where the flocculating rate of impurity is 90.1% and the loss rate of effective components of flavonoids is 0.8%. Zeta potential of the supernatant fluid was close to zero and the colloidal particles were under isoelectric state with the optimum dosage, which made the samples easy to flocculate and coagulate. Particles in the supernatant had diameters of 5~62 μm with an average particle diameter of ~10.88 μm. Most particles were precipitated comparing to the original liquids. The two-dimensional fractal dimension of the flocs has a maximum value of 1.43, which indicates that the flocs have compact structure.