壳聚糖对中药甘草水提液的絮凝效果及沉降模型

采用天然高分子絮凝剂壳聚糖对甘草水提液进行絮凝除杂，考察pH值及絮凝剂投加量对药液絮凝率、z电位及沉降速度的影响. 结果表明，在pH=6条件下，随絮凝剂投加量增加，z电位的绝对值先减小后增大，絮凝率先升高后降低，在有效絮凝范围内，沉降速度随投加量增加而加快，最佳絮凝剂投加量为0.347 g/L，此时药液的澄清度最高，絮凝率可达93.58%，z电位为-2.94 mV，最大沉降速度为18 mm/min. 在絮凝剂投加量为0.347 g/L时，随pH值增高，z电位的绝对值先减小后增大，絮凝率先升高后降低，沉降速度加快，最佳pH值为5，此时药液的澄清度最高，絮凝率可达94.53%，z电位为-2.04 mV，最大沉降速度为15 mm/min. 实验体系的z电位越接近等电点越有利于中药水提液的絮凝. 对实验数据回归建立了沉降速度模型，并利用颗粒沉降理论分析了其合理性.

Flocculation and Settling Model of Licore Water-leaching Solution with Chitosan

Chitosan was used to flocculate the licore water-leaching solution. The effects of pH value, the concentration of flocculant on flocculation rate, Zeta potential and settling velocity were examined. The results show that under the same pH condition, with the increase of flocculant dosage, the absolute value of Zeta potential first decreases and then increases, and the flocculation rate first increases and then decreases. In the range of effective flocculation, settling velocity increases with the increase of flocculant dosage. The optimal flocculant dosage is 0.347 g/L. The resulting solution has the highest clarity, flocculating rate can reach 93.58%, Zeta potential of 2.94 mV, the maximum subsidence velocity is 18 mm/min. Under the same condition of flocculant dosage, with the increase of pH value, the absolute value of Zeta potential first decreases and then increases, and the flocculation rate first increases and then decreases, settling velocity increases with the increase of pH value, the optimum pH value is 5, whereas the highest clarity of solution occurs, flocculation rate can reach 94.53%, Zeta potential is 2.04 mV, the maximum sedimentation velocity 15 mm/min. The closer the Zeta potential of experimental system to the isoelectric point, the more advantageous the flocculation of water leaching solution of traditional Chinese medicine. A settling velocity model was established through regression analysis on experimental data, and its rationality explained by the particle sedimentation theory in solid-liquid separation.