Removal of nitrogen oxides in membrane bioreactor
膜生物反应器处理一氧化氮废气研究

A hollow fiber membrane bioreactor was employed to remove nitric oxide (NO) in gas phase.Experiments were conducted to examine the performance of the membrane bioreactor in the long run and its recovery ability after the shutdown.In addition, the effects of NO inlet concentration, empty bed residence time (EBRT), spray flow rate and pH of liquid phase on the NO removal efficiency and coefficient of mass transfer were investigated as well.The membrane bioreactor exhibited a good stability in 100 days operation period, and recovered within one week after a 38-days shutdown.The high NO removal efficiency of 93.8% was achieved under the optimal conditions of pH 7.4, EBRT 32s and liquid spray rate 3 mL·min-1.Correspondingly, the coefficient of mass transfer was 7.39×10-5 mol·m-2·s-1.Due to the enhancement of the NO mass transfer between gas and liquid phase, the membrane bioreactor obtained promising improvement in NO removal efficiency.It also showed good capacity in resisting shock loading and considerable potential in adapting to the discontinuous production of NO gas in practice.