Spectroscopic studies of vanadium biosorption on different types of carbohydrate biomass
Bibliographic record
Abstract
The biosorption potential of different types of carbohydrate biomass is investigated to evaluate their application to purify water contaminated by vanadium in environmentally relevant oxidation states (V IV and V V ). Spectroscopic studies were done by electron paramagnetic resonance (EPR), vanadium nuclear magnetic resonance ( 51 V NMR), circular dichroism (CD), and electronic absorption in the visible range (vis). Both d-galacturonic and d-glucuronic acids are major components of plant cellular wall polysaccharides. The interaction of V IV with the model ligands d-galacturonic and d-glucuronic acids showed that complexation starts at low pH values (pH 3) and that carboxylate and sugar–OH groups, as well as water molecules, are involved in the coordination. At pH > 4.5, coordination promotes the sugar–OH deprotonation and new species form with the ligand chelating the metal ion via oxygen atoms of carboxylate and of adjacent sugar–O − donors. The studies with pectin and citric acid show the ability of both compounds to partially reduce V V to V IV in solution and the EPR parameters suggest coordination of carboxylate, sugar–OH, and water molecules. The interaction of V V with biomass from different sources shows that grapefruit, orange peel, and plane tree fruit are the most suitable candidates for the biosorption of vanadium. Studies with V V and grapefruit (or the grainless stalk of corn) indicate that the reduction takes place at the “surface” of the solid. EPR studies on the interaction of V IV with different carbohydrate biomass show their ability to complex high amounts of V IV . We propose that the biosorption mechanism, when the biomass is in contact with V V species, involves sorption, reduction, and retention at the surface level of V IV coordinated by oxygen donors of the biomass. When the interaction starts with V IV , the main process just involves the uptake of the metal ion at the surface level.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| 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) | 0.002 | 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 teacher head, 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".