Chromium (VI) photo‐reduction under visible and sunlight irradiation over bismuth‐ferrites Bi<sub>2</sub>Fe<sub>4</sub>O<sub>9</sub> photo‐catalyst
Bibliographic record
Abstract
Abstract The photo‐catalytic reduction of Cr(VI) in aqueous solution was investigated over spinel ferrites Bi 2 Fe 4 O 9 photo‐catalyst under both visible and solar light irradiation. The material was prepared by a low‐cost method and characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy dispersive x‐ray (EDX), Fourier transform infrared spectroscopy (FTIR), and diffuse reflectance spectroscopy (DRS). Electrochemical and photo‐electrochemical studies of the material were also explored. The Bi 2 Fe 3 O 9 structure had a small band gap (2.05 eV), which allowed the material to absorb more visible light. The photo‐electrochemical characterization in the presence of Na 2 SO 4 indicated that Bi 2 Fe 4 O 9 is a n ‐type semi‐conductor with a flat band of 0.77 V. The influence of the catalyst dose (0.25–1.5 g L −1 ), the initial concentration of Cr(VI) (25–125 mg L −1 ), and the irradiation source parameters on the photo‐catalytic performance of Bi 2 Fe 4 O 9 were studied at pH 2. The results indicated that the reduction rate of Cr(VI) depended on the catalyst's mass and the initial concentration of Cr(VI). By comparing the photo‐reduction activity under visible, ultrasonic, and solar irradiation, it became apparent that the presence of solar light increased the reduction efficiency. The Cr(VI) reduction rate was remarkably different when a combination of sonication and photo‐catalysis was utilized. This work indicated that Bi 2 Fe 4 O 9 can serve as a promising photo‐catalyst for the photo‐reduction of Cr(VI) under visible light irradiation.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.001 |
| Open science | 0.001 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| 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".