In two-chamber microbial electrolysis cells (MECs) with anion exchange membranes (AEMs), a phosphate buffer solution (PBS) is typically used to avoid increases in catholyte pH as Nernst equation calculations indicate that high pHs adversely impact electrochemical performance. However, ion transport between the chambers will also impact performance, which is a factor not included in those calculations. To separate the impacts of pH and ion transport on MEC performance, a high molecular weight polymer buffer (PoB), which was retained in the catholyte due to its low AEM transport and cationic charge, was compared to PBS in MECs and abiotic electrochemical half cells (EHCs). In MECs, catholyte pH control was less important than ion transport. MEC tests using the PoB catholyte, which had a higher buffer capacity and thus maintained a lower catholye pH (<8), resulted in a 50% lower hydrogen production rate (HPR) than that obtained using PBS (HPR = 0.7 m³-H₂ m⁻³ d⁻¹) where the catholyte rapidly increased to pH = 12. The main reason for the decreased performance using PoB was a lack of hydroxide ion transfer into the anolyte to balance pH. The anolyte pH in MECs rapidly decreased to 5.8 due to a lack of hydroxide ion transport, which inhibited current generation by the anode, whereas the pH was maintained at 6.8 using PBS. In abiotic tests in ECHs, where the cathode potential was set at −1.2 V, the HPR was 133% higher using PoB than PBS due to catholyte pH control, as the anolyte pH was not a factor in the performance. These results show that maintaining charge transfer to control anolyte pH is more important than obtaining a more neutral pH catholyte.

在具有阴离子交换膜（AEM）的两室微生物电解槽（MEC）中，磷酸盐缓冲溶液（PBS）通常用于避免阴极电解液pH升高，因为能斯特方程计算表明高pH会对电化学性能产生不利影响。但是，腔室之间的离子传输也会影响性能，这是那些计算中未包括的因素。为了分离pH和离子迁移对MEC性能的影响，将高分子量聚合物缓冲液（PoB）由于其低的AEM迁移和阳离子电荷而保留在阴极电解液中，与MEC和非生物电化学半电池中的PBS进行了比较。 （EHC）。在MEC中，阴极电解质pH控制的重要性不及离子迁移。使用PoB阴极电解液进行MEC测试，³ -H ₂ m ^-3 d ^-1）处，阴极电解液迅速增加至pH =12。使用PoB降低性能的主要原因是缺乏氢氧根离子转移到阳极电解液中以平衡pH值。由于缺乏氢氧根离子传输，MEC中的阳极电解液pH迅速降至5.8，这抑制了阳极产生的电流，而使用PBS将pH维持在6.8。在ECH的非生物测试中，阴极电位设置为-1.2 V，由于阴极电解液的pH控制，使用PoB的HPR比PBS高133％，因为阳极电解液的pH值不是性能的一个因素。这些结果表明，保持电荷转移以控制阳极电解液的pH比获得更中性的pH阴极电解液更为重要。