In the field of water treatment, UF membranes are widely used. The superior performance of UF membrane elements has also been well received. However, during the daily use of UF membranes, there may be some factors that affect their performance. So, what are the factors that affect the operation of UF membranes?
Appropriate pre-treatment can remove larger substances and lower the concentration in the solution, thus reducing the formation conditions of the covering layer.
Transmembrane pressure (TMP)
With the increase of pressure, the permeate flux rises rapidly at first, but when the pressure exceeds a certain value, there will be no obvious increase and even a decrease. This is because the increase in pressure will promote the further sedimentation of dissolved components, increasing the resistance of the covering layer to filtration.
Under certain operating conditions, the permeate flux changes with time can be divided into three stages: the first stage is the establishment stage of concentration polarization in a few minutes, which is manifested as a sharp drop in UF membrane flux; The second stage is the relatively rapid decline in about an hour, which is caused by the sedimentation of components; then it enters the third stage of slow decline within a few hours.
Within a certain range of pore size, with the increase of crossflow rate, the shear force on the covering layer increases, taking away the surface sedimentation of larger particles and thus increasing the membrane flux. However, it also increases the proportion of fine particles, leading to an increase in specific resistance and a decrease in membrane flux.
The influence of temperature on the permeate flux of UF membranes mainly lies in its effect on the viscosity and solubility of the solution. In dilute solutions, the influence is mainly manifested in its impact on viscosity.
Compared with traditional separation and purification methods, UF membrane separation technology has unique advantages in the Chinese medicine system:
The separation process has no phase change and low energy consumption, which is suitable for the separation and concentration of thermosensitive components in Chinese medicine.
No organic solvents are used, which can shorten production cycles, reduce the loss of effective ingredients, and be beneficial to environmental protection and safe production.
Choosing appropriate membrane materials can achieve higher separation selectivity, maintain the compatibility characteristics of the original formula, and ensure the therapeutic effect of the finished product.
The effect of impurity removal is good, which can significantly improve the clarity of liquid preparations such as oral liquids and injections, prolong the storage time, and can also remove bacteria and heat sources.
Continuous and automated operation can be achieved, and process parameters are stable and controllable, which is easy to be combined with other processes, and meets the requirements of modern Chinese medicine production. The application of UF membranes has effectively improved the various problems existing in the traditional process model and played a good role in clarifying and concentrating in the Chinese herbal medicine industry, thus saving a lot of costs for enterprises.