Study on filtration of bacitracin aqueous by ceramic membrane airlift nanofiltration equipment

Due to the advantages of low energy consumption and mild filtration condition, airlift nanofiltration equipment as a new type one has a potential wide application in purifying and separating bio-products. With bacitracin aqueous as the test media, the effects of aeration rate and transmembrane pressure drop on filtration performance of airlift nanofiltration equipment using TiO ₂ ceramic membrane with a pore size of 0.9 nm were investigated systematically. The results show that the aeration can efficiently improve the flux and trapped ratio. When transmembrane pressure drop is 0.3 MPa, both the steady flux and the steady rejection increase firstly with increasing aeration rate and reach the maximum when aeration rate is 100 L·h ^-1, then decrease with further increasing aeration rate. When aeration rate increase from 20 L·h ^-1 to 100 L·h ^-1, the steady flux and the steady rejection increase by 34.0% and 14.5%, respectively. On the other hand, the optimal aeration rate is 60 L·h ^-1, 100 L·h ^-1 and 140 L·h ^-1, respectively, when transmembrane pressure is 0.1 MPa, 0.3 MPa and 0.5 MPa. Meanwhile, based on mathematical modeling, the hydrodynamic and the energy consumption of airlift nanofiltration equipment at different operating conditions were also discussed.