Scalable Reactor Design for Electrocatalytic Nitrite Reduction with Minimal Mass Transfer Limitations
Scalable Reactor Design for Electrocatalytic Nitrite Reduction with Minimal Mass Transfer Limitations
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DOI：
10.1021/acsestengg.0c00054
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发表时间：
2020-11
期刊：
影响因子：
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通讯作者：
Chenxu Yan;Sruthi Kakuturu;Ashley Hesterberg Butzlaff;David M. Cwiertny;Syed Mubeen;C. Werth
中科院分区：
文献类型：
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作者：
Chenxu Yan;Sruthi Kakuturu;Ashley Hesterberg Butzlaff;David M. Cwiertny;Syed Mubeen;C. Werth
以Pd-In改性活性炭布为阴极，采用电位控制的平行板薄层流动反应器电催化去除水中的亚硝酸盐，考察了外加电位和流速对反应的影响。与文献中的其他反应器相比，在pH 6.5的磷酸盐缓冲溶液中，在施加电位为−0.60 V（相对于Ag/AgCl参比电极（RE））和流速为40 mL min-1时，观察到快速的亚硝酸盐还原（一级速率常数为0.38 L gPd-1 min-1），高电流效率（CE，51%）和低铵选择性（5.4%）。在更负的电位下观察到稍微更快的动力学（0.57 L gPd-1 min-1at-1.0 V/RE），但随后铵的产生（88%）、H2气体逸出（E0=-0.61V/RE）和电流损失（CE < 10%）变得有问题。亚硝酸盐还原在PPTL流动反应器中测量了近50个2小时的周期超过6个月，几乎没有明显的损失（30%）的活动。反应传输模型的开发和用于模拟动力学数据。拟合的本征速率常数kw = 5.2 × 10- 6 m·s-1，无因次Nusselt数与反应速率常数的比值支持反应器的反应大于传质限制。参数化模型的应用展示了如何缩放PPTL反应器（例如，阴极尺寸，流道厚度），操作（即，流速），或修改（即，更大的固有催化剂活性）以最有效地从较大的流动物流中除去亚硝酸盐。
A parallel-plate thin-layer (PPTL) flow reactor with potential control and custom-made cathode of Pd–In modified activated carbon cloth was developed for electrocatalytic removal of nitrite from water; the effect of applied potential and flow rate were investigated. Compared to other reactors in the literature, rapid nitrite reduction (first-order rate constant is 0.38 L gPd–1min–1), high current efficiency (CE, 51%), and low ammonium selectivity (5.4%) were observed at an applied potential of −0.60 V vs the Ag/AgCl reference electrode (RE) and a flow rate of 40 mL min–1in a phosphate buffer solution of pH 6.5. Slightly faster kinetics were observed at more negative potentials (0.57 L gPd–1min–1at −1.0 V/RE), but then ammonium production (88%), H2gas evolution (E0= −0.61 V/RE), and current loss (CE < 10%) became problematic. Nitrite reduction was measured in the PPTL flow reactor for almost 50 2 h cycles over six months, with little apparent loss (30%) in activity. A reactive transport model was developed and used to simulate the kinetic data. The fitted intrinsic rate constant (kw) was 5.2 × 10–6m s–1, and ratios of dimensionless Nusselt numbers to reaction rate constant values support the reactor being more reaction than mass transfer limited. Application of the parametrized model demonstrated how the PPTL reactor could be scaled (e.g., cathode dimensions, flow channel thickness), operated (i.e., flow rate), or modified (i.e., greater intrinsic catalyst activity) to most efficiently remove nitrite from larger flow streams.