CSIRO Land and Water, Floreat, WA 6014, Australia.
Bioresour Technol. 2013 Sep;143:25-31. doi: 10.1016/j.biortech.2013.05.108. Epub 2013 May 31.
Ammonium (NH4(+)) migration across a cation exchange membrane is commonly observed during the operation of bioelectrochemical systems (BES). This often leads to anolyte acidification (pH <5.5) and complete inactivation of biofilm electroactivity. Without using conventional pH controls (dosage of alkali or pH buffers), the present study revealed that anodic biofilm activity (current) could be sustained if recycling of ammonia (NH3) was implemented. A simple gas-exchange apparatus was designed to enable continuous recycling of NH3 (released from the catholyte at pH >10) from the cathodic headspace to the acidified anolyte. Results indicated that current (110 mA or 688 Am(-3) net anodic chamber volume) was sustained as long as the NH3 recycling path was enabled, facilitating continuous anolyte neutralization with the recycled NH3. Since the microbial current enabled NH4(+) migration against a strong concentration gradient (~10-fold), a novel way of ammonia recovery from wastewaters could be envisaged.
铵（NH4(+））在生物电化学系统（BES）运行过程中穿过阳离子交换膜的迁移是常见的。这通常会导致阳极电解液酸化（pH<5.5）和生物膜电活性的完全失活。如果不使用传统的 pH 控制（碱或 pH 缓冲剂的剂量），本研究表明，如果实施氨（NH3）的再循环，阳极生物膜活性（电流）可以维持。设计了一种简单的气体交换装置，以实现从阴极顶部空间连续回收 pH>10 时从阴极释放的 NH3（氨气）到酸化的阳极电解液中。结果表明，只要启用 NH3 再循环途径，就可以维持电流（110 mA 或 688 Am(-3) 净阳极室体积），从而利用回收的 NH3 持续中和阳极电解液。由于微生物电流使 NH4(+)能够在强浓度梯度（约 10 倍）下迁移，因此可以设想从废水中回收氨的新方法。
