Efficient electro-oxidation-based degradation of per- and polyfluoroalkyl (PFAS) persistent pollutants by using plasma torch synthesized pure-Magnéli phase-Ti4O7 anodes
Bibliographic record
Abstract
Pure Magnéli-phase Ti 4 O 7 were prepared by means of a Plasma Torch (PT) coating method and integrated into an advanced electro-catalytic oxidation (AEO) process in order to degrade perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS) persistent pollutants present in waters. The X-ray diffraction analysis confirmed the polycrystalline nature of the pure Magnéli phase PT-Ti 4 O 7 coatings (∼100 μm thick)). The Raman spectra of the PT-Ti 4 O 7 coatings also exhibited the two characteristic peaks (at 138 and 183 cm −1 ) of the PT-Ti 4 O 7 Magnéli phase. Scanning electron microscopy revealed the nanostructured hierarchical morphology of the PT-Ti 4 O 7 thus conferring them high surface area. The PT-Ti 4 O 7 anodes are shown to achieve higher degradation efficiencies towards PFOA and PFOS in comparison with the conventional boron-doped diamond anodes. By investigating several AEO parameters (including current density, treatment time, nature of the anode material), we were able to optimise the AEO process. Thus, for both PFOA and PFOS (at an initial concentration of 500 ppb in synthetic wastewaters), degradation efficiencies as high as 96.6% and 99.7% were achieved, respectively, with a current density of 20 mA/cm 2 , a treatment time of 120 min and PT-Ti 4 O 7 mesh-type anodes. PFOA and PFOS can be degraded by both direct anodic electrochemical oxidation ( • OH radicals) and indirect electrochemical oxidation via mediators, such as persulphate acid (H 2 S 2 O 8 ) generated by sulphate anodic oxidation. The degradation of both compounds followed pseudo-first-order kinetics. The reaction rate constant (k) for PFOS removal was 4.63 × 10 −2 min −1 , whereas 2.76 × 10 −2 min −1 was recorded for PFOA removal. Subsequently, we have used the above optimal AEO operating conditions to treat real wastewater effluents (containing 17 types of PFAS molecules with a total content of 8500 ppb) and achieved a degradation rate of 39.1%–87.4% for eight of the 17 PFAS compounds. The degradation rate was found to be dependent on the chemical structure and chain length of each PFOA/PFOS component. • Ti 4 O 7 anode was prepared by means of a PT method and used in AEO process. • The deposited Ti 4 O 7 coating had a polycrystalline nature of the Magnéli-phase. • PT-Ti 4 O 7 -Mesh was more effective than PT-Ti 4 O 7 -Plate for PFAS degradation. • At least 96% of PFOA and PFOS were removed in synthetic effluents. • 17 PFAS at 8500 ppb in real wastewater, 39.1–87.4% degradation was achieved.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
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 | 0.000 | 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 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".