Nitrogen oxides (NOx) are one of the most important air pollutants, mainly caused by the combustion of fossil fuels and nitric acid production processes. The hollow fiber membrane biofilm reactor (HFMBR) is a suitable candidate for treatment of biodegradable gases such as NO which has a very low water solubility. In this study, NOx removal performance by denitrification process in an HFMBR using a non-porous polydimethylsiloxane (PDMS) based hollow fiber membrane (HFM) under various conditions was evaluated. A bioreactor was operated for 171 days under varying values of NO inlet load (44.6-89.2 mg m^-2day^-1), nitrate concentration (0-40 mg NO₃--N L^-1), membrane inner pressure (0-400 mbarg), and different gas supplying modes as flow-through (open-end) or dead-end (closed-end). During this mode NO could be transferred completely from the gas phase to the biofilm, resulting in an increase in the removal efficiency. Over 4 weeks, the effect of gas supplying mode with a periodical switch of open-end/closed-end was evaluated for different on/off durations. 500 ppm NO/N₂ gas was fed through the lumen of the membranes with a flow rate of 10 mL min^-1 for 60, 30, and 15 seconds and gas outlet port was closed by the solenoid valve for an another 60, 30, and 15 seconds, respectively. The highest removal efficiency was obtained as 91% when on/off time was 30/30 sec. Results showed that overall performance of the reactor can be increased by modifying inner membrane pressure and gas supplying strategy.

氮氧化物（NOx）是最重要的空气污染物之一，主要由化石燃料燃烧和硝酸生产过程引起。中空纤维膜生物膜反应器（HFMBR）是适合用于处理水溶性极低的可生物降解气体（如NO）的候选材料。在这项研究中，评估了使用无孔聚二甲基硅氧烷（PDMS）基中空纤维膜（HFM）在各种条件下通过HFMBR进行的反硝化过程去除NOx的性能。生物反应器在NO入口负荷（44.6-89.2 mg m ^-2 day ^-1），硝酸盐浓度（0-40 mg NO ₃ --NL ^-1）的变化值下运行171天），膜内部压力（0-400 mbarg），以及不同的供气方式，如流通式（开放式）或闭式（封闭式）。在此模式下，NO可以完全从气相转移到生物膜，从而提高去除效率。在4周的时间内，针对不同的开/关时间，评估了采用开放式/封闭式定期开关的供气模式的效果。将500 ppm NO / N ₂气体以10 mL min ^-1的流速通过膜腔分别关闭60、30和15秒，然后用电磁阀将出气口分别关闭60、30和15秒。当开/关时间为30/30秒时，最高去除效率为91％。结果表明，通过改变内膜压力和气体供应策略可以提高反应器的整体性能。