Catalytic hydrothermal conversion of polypropylene at sub-critical conditions with Ni-supported zeolites
Bibliographic record
Abstract
Hydrothermal plastic processing is a developing technology that can provide a clean pathway for plastic waste disposal. In this work, the use of catalyzed hydrothermal conversion in subrcritical conditions was evaluated with nickel impregnated zeolite catalysts. Previously, catalysis of hydrothermal conversion had scarcely been reported on polypropylene (PP) feedstock. Here we screened the activity of various nickel-based catalysts supported on zeolite, titanium oxide and magnesium oxide at 350 °C and 20.7 MPa for 1 h. At these conditions, up to 20 % gas yield was obtained, producing 215 g of C 3 H 8 per kg of PP feedstock using the nickel impregnated zeolite catalyst I. Analysis of oil products showed the presence of aromatic compounds, notably p- tert -butylphenol, as well as the presence of fatty acids such as n-hexadecanoic acid in select samples. This process offers a basis for the catalytic conversion of polypropylene feedstock into gas and oil products below supercritical water conditions.
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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 | 0.000 | 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".