Optimisation of preparation of hazelnut shell activated carbon for adsorption of Cr (III)
Bibliographic record
Abstract
The aim of this study was the optimisation of the activated carbon (C) production process by dehydration–carbonisation using concentrated sulfuric acid (H2SO4) from hazelnut shells found locally and readily available agricultural waste and the adsorption of chromium (III) (Cr3+) on the activated carbon produced by this method. An adsorption experiment was carried out at conditions of 25°C and initial concentration of 30 mg chromium (III)/l. The optimum process conditions for ensuring maximum adsorption capacity were investigated by means of statistically designed experiments and steepest ascent experiments. The optimum values found were an impregnation ratio of 4.5 ml sulfuric acid/g hazelnut shells, an oven temperature of 50°C, a holding time in the oven of 19.8 h and a maximum adsorption capacity of 14.76 mg chromium (III)/g hazelnut shell activated carbon (HSAC). The surface properties of HSAC were investigated by scanning electron microscopy and Fourier transform infrared spectroscopy and agreed with the outcomes. The adsorption mechanism could be rapid ion exchange and slow chemisorption and/or an outer-sphere complexation at pH 3.5–6.0 during the process.
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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".