Experimental study on flocculating effect of Chinese herbs licorice water-extract liquid based on ζ potential / 中草药

ABSTRACT

Objective: Study on the influence of ζ potential on flocculating rate of Chinese herbs water-extract liquid. Methods: Chitosan of natural macromolecule flocculant was adopted to remove the flocculation impurity of the herb licorice (Glycyrrhizae Radix) extract, and the deep connection between ζ potential and liquid flocculating rate was proved by single factor experiment, orthogonal experiment, and granularity. Results: Under the influence of single factor conditions, absolute value of ζ potential of the system is lower, while the flocculation rate is higher. Based on orthogonal experiment, the optimum process condition of flocculating licorice extract is determined to be the flocculant dosage quantity of 0.347 g/L, pH value of 6, temperature of 30℃, and the system ζ potential of -1.67 mV, which is close to the isoelectric point among all the experiment. Whereas the flocculating rate was as high as 95.29%. The ζ potential of solution before flocculation is -14.78 mV, the average particle size is 17.12 μm; After the flocculation the ζ potential of clear liquid is -1.67 mV, the average particle size is 6.77 μm. The change of ζ potential affected the particle behavior of sol system and ultimately affected the liquid flocculating rate. Conclusion: In the process of flocculating herb licorice extract, the ζ potential has the important influence on the flocculation of herb extract. Absolute value of ζ potential of the system is lower, closer to the isoelectric point, the flocculation rate is higher. The ζ potential that reflects the flocculation essence provides a strong justification for the selection of flocculation conditions.