Chlorine regeneration of a zeolite ion-exchange column for ammonia removal from an explosives-impacted mining wastewater
Bibliographic record
Abstract
Zeolite ion-exchange column system has been suggested as a viable option for the removal of total ammonia nitrogen (TAN) from explosives-impacted mining wastewater (EIMWW) in cold regions. The objective of this bench-scale study was to compare the effectiveness of several NaOCl, NaOCl-NaCl and NaCl regeneration solutions on the performance of a zeolite column loaded with a synthetic EIMWW. The NaOCl experiments confirmed that effluent pH, total chlorine level, and free chlorine levels during the chlorine regeneration were positively related, thus indicating that ammonia is oxidized to nitrogen gas accompanied by production of hydrogen ions. This led to the regeneration of TAN-containing sites but it also regenerated sites containing K and Ca, this appears to be accomplished through the Na ions in the NaOCl solution and H+ ions generated in the breakpoint chlorination reaction. The three regeneration schemes worked effectively, they did not significantly impact TAN uptakes and TAN selectivity. The NaOCl-NaCl regeneration scenario was superior to the NaOCl regenerations as it was faster and resulted in shorter low-pH periods that may damage the zeolite. And unlike the NaCl regeneration, the NaOCl-NaCl used regenerant was essentially TAN free, so it permits regenerant reuse and avoids creating a secondary waste stream. Thus, zeolite column treatment coupled with NaOCl-NaCl regeneration is a practical approach for the treatment of TAN-laden EIMWW.
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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 | 0.001 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 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".