Gold adsorption from cyanide solution by chitinous materials
Bibliographic record
Abstract
Abstract Adsorption of AuCN2− by chitinous materials such as acid‐washed crab‐shells burnt crab‐shells, as well as by chitin modified by quaternization of amine was affected by the pH of the sorption system. The maximum AuCN2− uptake by acid‐washed crab‐shells occurred at pH 3.7 corresponding to a final Au concentration of 0–0.025 mM. While this material did not bind any AuCN2− at pH 10, crab‐shells burnt in a non‐oxidizing atmosphere removed 90% of the metal under these alkaline conditions. SEM with EDXA analysis of the biosorbent showed that the heat treatment changed the ratio of C/O and created a highly porous material structure. FTIR results indicated that phenolic groups were the main sites responsible for AuCN2− binding on burnt acid‐washed shells. Chitin, the main component of crab‐shells, was modified by grafting tertiary amine to C‐3 and C‐6 on chitin to create quaternary amine groups. The presence of quaternary amine groups also made AuCN2− uptake possible at pH10. The results confirmed that certain chitinous materials are capable of effectively removing and concentrating anionic gold cyanide from both acidic and alkaline solutions if pretreated by appropriate physical or chemical methods. © 2001 Society of Chemical Industry
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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) | 0.001 | 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".