Continuous Monitoring of Free Chlorine Level and pH Using an Array of Carbon Nanotube Chemiresistors
Bibliographic record
Abstract
Free chlorine (FC) is the most commonly used disinfectant in water treatment plants, both as a primary disinfectant for pathogen removal and as a secondary disinfectant to suppress pathogen growth in the distribution system. The "disinfectant power" is dependent on the concentration of FC as well as the pH of the water. Continuous monitoring of FC level and pH is crucial to ensure safe drinking water; however, currently used methods involve either frequent calibration or reagents. Here, an array of single-walled carbon nanotube (SWCNT) chemiresistors is demonstrated for the continuous monitoring of FC at different pHs. The SWCNT chemiresistors were noncovalently functionalized with cobalt phthalocyanine and anthraquinone. The array has been shown to differentiate FC concentrations ranging from 0.03 to 2.1 mg/L within a pH range of 6.5 to 9.5. In addition, sensor design has been improved from our previous devices to incorporate components to facilitate mass fabrication. This design was tested over a wide range (0.015-10 mg/L) of FC. The limit of detection (LOD) of the sensor was calculated to be 0.001 mg/L. An electronic reset function is incorporated into the sensors to be able to continuously monitor the concentration of FC. The durability of the sensors is demonstrated with repeated measurements in simulated tap water. Overall, this study presents electrical sensor-based continuous monitoring of FC.
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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".