荷叶水提液的絮凝优化工艺及其失活动力学研究

为考察复合絮凝剂(壳聚糖、单宁)的絮凝活性,优化荷叶水提液絮凝工艺条件,对絮凝剂的投加量、温度、搅拌速度进行了水平正交实验.实验结果表明荷叶水提液的最佳工艺条件为:壳聚糖投加量为1.071g/L,单宁投加量为5.357g/L,温度为30℃,转速为60r/min.并在此工艺条件的基础上进行絮凝剂的失活动力学实验研究.实验表明,荷叶水提液在25℃—30℃范围内絮凝选择性好,絮凝活性高;高于30℃时,絮凝活性显著下降.同时验证了复合絮凝剂的失活动力学符合一级反应的失活动力学模型,并讨论了时间、温度同絮凝率及黄酮损失率的关系,并由此推算出失活速率常数、活化能等动力学函数值.为荷叶水提液的絮凝工艺研究及操作条件的选择提供了有价值的理论依据.

The Optimum Flocculation Process and Inactivation Kinetics of Lotus Leaf Water-extraction

In order to study the flocculation activity of composite flocculants(chitosan、tannin),optimize the flocculation process conditions of lotus leaf water-extraction,the dosage of flocculants,temperature and the stirring rate were examined by orthogonal experiments.The best flocculation process parameters were as follows:the dosage of chitosan was 1.071g/L;the dosage of tannin was 5.357g/L;the temperature was 30℃;the stirring rate was 60r/min,respectively.The inactivity kinetics of the flocculant experiments were established on the basis of process above.It was indicated by the results that the lotus leaf water-extraction solution had a good selection on flocculation in range of 25℃—30℃.When the temperature was higher than 30℃,the flocculation activity was descended obviously.At the same time,it was proved that the inactivity kinetics of composite flocculants agreed with the first-order inactivity kinetic model.The relation of time、temperature with the rate of flocculation and the losing rate of flavonoids were discussed,and gain the function values of kinetic parameters K and E.The method would be useful for the flocculant process design and operating condition selection of lotus leaf water-extraction.