Effects of Chain Length and Electrolyte on the Adsorption of <i>n</i>-Alkylpyridinium Bromide Surfactants at Sand−Water Interfaces
Bibliographic record
Abstract
The kinetic and equilibrium studies of the adsorption of four cationic surfactants (pyridinium bromide) with different chain lengths (C 16, C 14, C 12, and C 10 ) onto sand are presented here. The adsorption and desorption behavior in the absence and presence of different electrolytes (NaCl, CaCl 2, and Na 2 SO 4 ) are compared in batch and continuous column experiments. The kinetic studies show that the rates of adsorption of pyridinium bromide surfactants on sand surfaces are very high (∼70% of saturation adsorption occurs in 30 s) and are almost the same at low concentration (0.5 mM) for different chain lengths. The amount of surfactant adsorbed is enhanced by the presence of electrolyte because of a reduction in electrostatic repulsion among the headgroups, whereas the effect of the valence of coion does not appear to be important. Desorption studies based on column experiments show that a lower amount of surfactant is retained when eluted with electrolyte solution instead of pure water.
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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) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 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".