Influence of electrolyte species and concentration on the aggregation and transport of fullerene nanoparticles in quartz sands
Bibliographic record
Abstract
The potential toxicity of nanoscale particles has received considerable attention, but the fate of engineered nanomaterials in the environment has been studied only under a limited set of conditions. In the present study, batch and column experiments were performed to assess the aggregation and transport of nanoscale fullerene (nC60) particles in water-saturated quartz sands as a function of electrolyte concentration and species. As the electrolyte concentration increased from 1 to 100 mM, the change in nC60 particle diameter was minimal in the presence of NaCl but increased by more than sevenfold in the presence of CaCl2. The latter effect was attributed to the agglomeration of individual nC60 particles, consistent with a net attractive force between particles and suppression of the electrical double layer. At low ionic strength (3.05 mM), nC60 particles were readily transported through 40- to 50-mesh quartz sand, appearing in the column effluent after introducing less than 1.5 pore volumes of nC60 suspension, with approximately 30% and less than 10% of the injected mass retained in the presence of CaCl2 or NaCl, respectively. At higher ionic strength (30.05 mM) and in finer Ottawa sand (100-140 mesh), greater than 95% of the introduced nC60 particles were retained in the column regardless of the electrolyte species. Approximately 50% of the deposited nC60 particles were recovered from 100- to 140-mesh Ottawa sand after sequential introduction of deionized water adjusted the pH to 10 and 12. These findings demonstrate that nC60 transport and retention in water-saturated sand is strongly dependent on electrolyte conditions and that release of deposited nC60 requires substantial changes in surface charge, consistent with retention in a primary energy minimum.
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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 | 0.001 |
| 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 | 0.001 | 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".