Degradation of bisphenol A by the UV and UV/H<sub>2</sub>O<sub>2</sub> processes: Evaluation of process variables through experimental design
Bibliographic record
Abstract
Abstract UV‐based technologies have been proposed for the treatment of wastewater containing bisphenol A (BPA), a toxic, endocrine‐disruptor pollutant. Nevertheless, the evaluation of the role of process variables through experimental design has not been previously addressed. In this study, the effects of BPA and H2O2 initial concentrations, and specific photon emission rate (EP,0) on BPA degradation by the UV and UV/H2O2 processes were investigated, using the Doehlert design and response surface analysis. The experiments were performed in a tubular reactor equipped with a 254‐nm UV lamp, for [H2O2]0 and EP,0 in the ranges 1.6–9.6 mmol · L−1 and 0.87 × 1018–3.6 × 1018 photons · L−1 · s−1, respectively. Photolysis ([BPA]0 = 10–50 mg · L−1) was shown to be inefficient for BPA degradation and mineralization, with pollutant removals lower than 55 %. The specific BPA photolysis rate and BPA removal decreased with increasing [BPA]0. In contrast, all the UV/H2O2 experiments ([BPA]0 = 50 mg · L−1) resulted in total BPA degradation after 60 min of irradiation. In this case, the best conditions were [H2O2]0 = 7.6 mmol · L−1 and Ep,0 = 3.6 × 1018 photons · L−1 · s−1, achieving the highest BPA degradation rate and removal after 15 min, and the second highest TOC removal after 180 min. In most experiments less than 75 % TOC removal was achieved, with 95 % mineralization observed solely for the highest [H2O2]0 and EP,0. In any case, the residual toxicity and endocrine activity of treated solutions must be determined, in order to prove the applicability of the UV/H2O2 process for real water and wastewater treatment.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.001 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.001 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.001 | 0.001 |
| 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 source (direct Gemma or distilled Codex), 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".