小孔径陶瓷膜澄清甜叶菊提取液的工艺研究

杨文银; 赵士明; 章小同; 朱传柳; 葛乃星

doi:10.13386/j.issn1002-0306.2020090012

小孔径陶瓷膜澄清甜叶菊提取液的工艺研究

Study on the Clarification Process of Stevia Extract by Small-Aperture Ceramic Film

摘要

摘要: 该文研究了小孔径陶瓷膜澄清甜叶菊提取液的效果。通过比较4、5、8、10 nm孔径的陶瓷膜过滤甜叶菊的甜菊糖提取液时的过滤通量、脱色率和收率的区别，确定较优的陶瓷膜孔径；再优化陶瓷膜操作参数。结果表明，5 nm陶瓷膜较优，在40 ℃时，操作压力5 bar，膜面流速4 m/s，浓缩10倍，加30%原液体积水洗滤效果最佳，陶瓷膜平均过滤通量可达102.6 kg/（m²·h），甜菊糖收率可达99.2%，陶瓷膜过滤结束后先利用质量分数1%~2%的NaOH清洗1 h，再用0.5%~1%硝酸清洗1 h，陶瓷膜水通量恢复率可以达到99%以上，再生效果比较好，可以重复使用。相比絮凝工艺，陶瓷膜脱色率提高了2.6%，甜菊糖收率提高了6.8%，因此膜法工艺可取代传统絮凝工艺实现对甜叶菊提取液的澄清。

Abstract: In this paper, the effect of small pore size ceramic membrane clarifying stevia extract was studied. By comparing the filtration flux, decolorization rate and yield of stevia extract with different pore size, the better pore size of ceramic membrane was determined, and the operating parameters of ceramic membrane were optimized. The results showed that the ceramic membrane of 5 nm was better. At 40 ℃, the operating pressure was 5 bar, the flow rate of the membrane surface was 4 m/s, concentrated 10 times, and the filtration effect of 30% raw liquid water was the best. The average filtration flux of ceramic membrane was 102.6 kg/(m²·h) and the yield of stevia was 99.2%. After filtration, the ceramic membrane was cleaned for 1 h by 1%~2% NaOH, and then 0.5%~1% nitric acid was used for 1 h. The recovery rate of ceramic membrane water flux could reach more than 99%, and the regeneration effect was good and could be reused. Compared with the flocculation process, the decolorization rate of ceramic membrane increased by 2.6% and the yield of stevia increased by 6.8%. Therefore, the membrane process can replace the traditional flocculation process to clarify the extract of stevia.