陶瓷膜和有机膜超滤处理荔枝汁和膜垢分析及荔枝汁品质研究

应用陶瓷膜和有机膜对荔枝汁进行澄清实验，并进行采用总循环模式(TRM)研究跨膜压力(TMP)和循环流量(Qf)对膜通量(Qp)的影响，确定其各自的最优水平；采用批处理模式(TBM)研究这两个参数最优水平的组合工艺。澄清工艺中：无机陶瓷膜效果优于有机聚醚砜膜，最佳工艺条件为陶瓷膜组件、TMP 0.3MPa、Qf 40L/min。研究在TBM下，膜垢的形成原因，对微分方程--＝k(J－Jlim)J2－n进行拟合，拟合R2为无机膜0.8812和0.8478；有机膜为0.9048，并分析膜垢的形成的模式：有机膜的膜垢主要是层垢(n＝0)，无机膜的膜垢形成主要是层垢和部分并在膜垢的综合情况(n＝0，n＝1)。并研究TBM模式下，总糖、总果胶、总蛋白、抗氧化活性等影响果汁品质的物质的动态过程，结果表明：在P＜0.05，无机膜在品质的保持比如总糖、抗氧化活性、总酚的截留滤等方面强于有机膜，其余的品质无显著差异。

Treatment of Lychee Juice with Ceramic or Polyether Sulfone Ultrafiltration Membranes: Analysis of Membrane Fouling and Lychee Juice Quality

The objective of this study was to develop a membrane separation process for the clarification of lychee juice.The effects of trans-membrane pressure(TMP) and axial feed flow rate(Qf) on permeation flux(Qp) under total recycle mode(TRM) during the clarification of lychee juice with ceramic or polyether sulfone membranes were investigated to determine their individual optimal levels.Further,their optimal levels were analyzed when considered concurrently under batch treatment mode.Ceramic membrane was more effective in clarifying lychee juice than polyether sulfone membrane.The optimal operating conditions for clarifying lychee juice with ceramic membrane were determined as 0.3 MPa of TMP and 40 L/min of Qf.Meanwhile,the cause of membrane fouling under batch treatment mode was explored.The R2 obtained from fitting dJ/dt = k(J-Jlim) J2-n was 0.8812 and 0.8478 for ceramic membrane and 0.9048 for polyether sulfone membrane.Membrane fouling depended on cake filtration(n = 0) for polyether sulfone membrane and dynamic changes between partial pore blocking(n = 1) and cake filtration(n = 0) for ceramic membrane.The dynamic changes of total sugar,total pectin,total protein,antioxidant ability were examined during membrane filtration under batch treatment mode.Ceramic membrane was significantly more effective in maintaining some quality indexes such as total sugar,antioxidant activity and total phenol than polyether sulfone membrane,while no significant difference was observed in other quality indexes.