Adsorption of carbamazepine from water by hydrothermally and steam activated agricultural by-products: equilibrium, site energy, and thermodynamic studies
Bibliographic record
Abstract
Pollution of water sources by pharmaceuticals has attracted attention. In this work, carbamazepine (CBZ), as a model pharmaceutical pollutant, was used to investigate its characteristics of adsorption from an aqueous solution. Flax shives and oat hulls, representing cellulosic materials of agricultural by-products, were characterized and used to develop hydrochars and steam activated hydrochars adsorbents. Hydrothermal treatment and steam activation significantly enhanced the CBZ adsorption capacity. The isotherms of CBZ adsorption by the steam activated hydrochars were experimentally investigated at various temperatures (20–40 °C) and satisfactorily simulated by the Sips model. The steam activated hydrochars of flax shives and oat hulls had higher maximum CBZ adsorption capacities of 293.5 and 162.6 mg/g than the respective hydrochars (75.3 and 81.8 mg/g) and raw materials (16.5 and 15.0 mg/g). Based on the isotherm modeling results, the site energy distribution of CBZ adsorption was further determined. The weighted means of site energy obtained at 40 °C (13.3–15.0 kJ/mol) were higher than those at 30 °C (11.2–13.4 kJ/mol) and 20 °C (7.7–8.0 kJ/mol), indicating higher adsorption affinity, thus more favorable adsorption. Furthermore, the thermodynamic parameters of CBZ adsorption were determined. The results indicated that the CBZ adsorption on hydrochars and steam activated hydrochars were endothermic and spontaneous.
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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) | 0.001 | 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".