Preparation And Kaempferol Seperation Research Of Polyacrylonitrile Molecularly Imprinted Membranes

As a flavonoid, the kaempferol has very high medical value, thus the kaempferol separation and purification from pharmaceutical waste liquor can not only reduce the biochemical load during the water treatment engineering, but also bring economic value. The traditional methods of the kaempferol separation are usually complex and cause the environmental pollution and waste of resources easily. In this study, the kaempferol in the liquid was separated through the molecularly imprinted membrane technology, which combines the molecularly imprinted technology and the membrane separation technology.In this paper, polyacrylonitrile (PAN) and N,N-dimethylformamide (DMF) were used as the polymer and solvent, respectively. The effects of inorganic additives, organic additives, blending additives, template molecule kaempferol and molecularly imprinted polymer microsphere concentrations on membrane performance and gelation process were studied. The optimized kaempferol molecularly imprinted membrane composition was confirmed as follow:10.0 wt.% PAN,1.0 wt.% Mg(C104)2,1.5 wt.% polyethylene oxide-poly propylene oxide-polyethylene oxide triblock copolymer (PEO-PPO-PEO) and 1.5 wt.% kaempferol, the polymer microsphere molecularly imprinted membrane composition was determined as follow:10.0 wt.% PAN,1.0 wt.% Mg(C104)2,1.5 wt.% PEO-PPO-PEO and 0.1 wt.% imprinted polymer microspheres.The two kinds of molecularly imprinted membrane were applied for kaempferol separation and the experimental results showed that as the kaempferol concentration or the operating pressure increased, the separation quantity went up gradually. As the temperature of the liquid was higher than 30℃, the kaempferol separation quantity decreased. With the operating time increasing to 30 minutes, the separation quantity went up gradually and then tended to be saturated, the separation quantity with polymer microsphere molecularly imprinted membrane was 14.6 mg/m2 while the separation quantity with kaempferol molecularly imprinted membrane was 8.1 mg/m2, however, the kaempferol elution quantity through backwashing with the former was lower than that with the latter. When the kaempferol concentration was 25 mg/L, the operating condition was 50 kPa and 30℃, and the separation quantity with polymer microsphere molecularly imprinted membrane was 7.2 mg/m2 while the separation quantity with kaempferol molecularly imprinted membrane was 3.5 mg/m2 after operating for 5 minutes.