Ammonium crossover as a function of membrane type and operating conditions in flow cells for ammonia synthesis and water treatment applications
Bibliographic record
Abstract
Abstract Electrochemical flow cells are promising designs for both ammonium () electrosynthesis from dinitrogen and removal/recovery from wastewater. The crossover is undesirable for electrosynthesis but is favourable for removal. The crossover is investigated herein under different current densities, concentrations, and feed locations using cation‐exchange (Nafion N112, N350) and anion‐exchange (Sustainion X37‐50) membranes and microporous diaphragms (Celgard 3400, 3500, and 5550). For Nafion N112, the crossover from catholyte to anolyte decreases with higher concentrations from 81.9 ± 4.7% at 1 ppm to 10.7 ± 0.7% at 3400 ppm. At a constant concentration, increasing the current density leads to more intense electrolyte pH polarization, which leads to volatilization in favour of recovery up to 78.1 ± 1.1% at a cathode superficial current density of −10 A m −2 . When comparing the recovery efficiency, the cathode‐ and symmetric fed operations were outperformed by the anode‐fed mode for 3400 ppm due to the equilibrium that buffers the pH change. For Celgard diaphragms, modest crossover (<5%) was only demonstrated at low current densities (≤−1 A m −2 ), but the separation was compromised by the bulk electrolyte transport through micropores and electrolysis‐induced pH polarization, highlighting future needs to develop and rigorously verify separators toward electrosynthesis.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.000 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one teacher head, not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".